The Definitive Guide to Jython: Python for the Java Platform.pdf

【实例截图】

【核心代码】

Contents
Contents at a Glance...........................................................................................................................iii
Contents ............................................................................................................................................... v
Foreword ........................................................................................................................................... xix
About the Authors.............................................................................................................................. xx
About the Technical Reviewers....................................................................................................... xxii
Acknowledgments .......................................................................................................................... xxiii
Introduction..................................................................................................................................... xxvi
Part I: Jython Basics: Learning the Language....................................................................................1
■ Chapter 1: Language and Syntax....................................................................................................3
The Difference between Jython and Python........................................................................................ 4
Installing and Configuring Jython ....................................................................................................... 4
Identifiers and Declaring Variables ..................................................................................................... 5
Reserved Words................................................................................................................................. 6
Coding Structure................................................................................................................................ 6
Operators........................................................................................................................................... 8
Expressions ....................................................................................................................................... 8
Functions........................................................................................................................................... 9
Classes ............................................................................................................................................ 10
Statements ...................................................................................................................................... 11
if-elif-else Statement ................................................................................................................... 12
print Statement............................................................................................................................ 13
try-except-finally ......................................................................................................................... 15
raise Statement ........................................................................................................................... 16
import Statement......................................................................................................................... 17
Iteration ........................................................................................................................................... 17
While Loop................................................................................................................................... 19
For Loop ...................................................................................................................................... 20
Basic Keyboard Input ....................................................................................................................... 20
■ CONTENTS
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Other Python Statements ................................................................................................................. 21
Documenting Code........................................................................................................................... 22
Python Help ..................................................................................................................................... 23
Summary ......................................................................................................................................... 24
■ Chapter 2: Data Types and Referencing .......................................................................................25
Python Data Types ........................................................................................................................... 25
Strings and String Methods.......................................................................................................... 27
String Formatting..................................................................................................................... 31
Lists, Dictionaries, Sets, and Tuples............................................................................................. 33
Lists ........................................................................................................................................ 33
List Comprehensions ............................................................................................................... 40
Tuples ..................................................................................................................................... 41
Dictionaries ............................................................................................................................. 42
Sets......................................................................................................................................... 45
Ranges .................................................................................................................................... 48
Range Format.......................................................................................................................... 49
Jython-specific Collections .......................................................................................................... 50
Files............................................................................................................................................. 52
Iterators ....................................................................................................................................... 54
Referencing and Copies ............................................................................................................... 55
Garbage Collection....................................................................................................................... 57
Summary ......................................................................................................................................... 58
■ Chapter 3: Operators, Expressions, and Program Flow ...............................................................59
Types of Expressions ....................................................................................................................... 59
Mathematical Operations ................................................................................................................. 59
Comparison Operators ................................................................................................................. 63
Bitwise Operators ........................................................................................................................ 65
Augmented Assignment ............................................................................................................... 66
Boolean Expressions .................................................................................................................... 68
Conversions ................................................................................................................................. 70
Using Expressions to Control Program Flow...................................................................................... 72
if-elif-else Statement ................................................................................................................... 72
while Loop ................................................................................................................................... 73
continue Statement...................................................................................................................... 74
break Statement .......................................................................................................................... 75
■ CONTENTS
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for Loop ....................................................................................................................................... 76
Example Code.............................................................................................................................. 77
Summary ......................................................................................................................................... 79
■ Chapter 4: Defining Functions and Using Built-ins ......................................................................81
Function Syntax and Basics.............................................................................................................. 81
The def Keyword.......................................................................................................................... 82
Naming the Function.................................................................................................................... 82
Function Parameters and Calling Functions.................................................................................. 84
Recursive Function Calls .......................................................................................................... 86
Function Body.............................................................................................................................. 86
Documenting Functions ........................................................................................................... 86
Returning Values...................................................................................................................... 87
Introducing Variables ............................................................................................................... 88
Other Statements..................................................................................................................... 89
Empty Functions ...................................................................................................................... 89
Miscellaneous Information for the Curious Reader............................................................................ 90
Built-in Functions............................................................................................................................. 90
Alternative Ways to Define Functions ............................................................................................... 90
Lambda Functions ....................................................................................................................... 91
Generator Functions......................................................................................................................... 91
Defining Generators ..................................................................................................................... 92
Generator Expressions ................................................................................................................. 95
Namespaces, Nested Scopes, and Closures ..................................................................................... 95
Function Decorators......................................................................................................................... 96
Coroutines ....................................................................................................................................... 99
Decorators in Coroutines............................................................................................................ 101
Coroutine Example..................................................................................................................... 102
Summary ....................................................................................................................................... 102
■ Chapter 5: Input and Output........................................................................................................105
Input from the Keyboard................................................................................................................. 105
sys.stdin and raw_input............................................................................................................. 105
Obtaining Variables from Jython Environment ............................................................................ 106
File I/O........................................................................................................................................... 107
Pickle............................................................................................................................................. 110
Output Techniques..................................................................................................................... 111
■ CONTENTS
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Summary ....................................................................................................................................... 112
■ Chapter 6: Object-Oriented Jython .............................................................................................113
Basic Syntax .................................................................................................................................. 113
Object Attribute Lookups................................................................................................................ 117
Inheritance and Overloading........................................................................................................... 119
Underscore Methods ...................................................................................................................... 121
Protocols........................................................................................................................................ 123
Default Arguments ......................................................................................................................... 127
Runtime Binding of Methods .......................................................................................................... 128
Caching Attribute Access ............................................................................................................... 128
Summary ....................................................................................................................................... 131
■ Chapter 7: Exception Handling and Debugging..........................................................................133
Exception Handling Syntax and Differences with Java .................................................................... 133
Catching Exceptions................................................................................................................... 134
Raising Exceptions..................................................................................................................... 142
Defining Your Own Exceptions........................................................................................................ 143
Issuing Warnings ........................................................................................................................... 143
Assertions and Debugging.............................................................................................................. 148
Context Managers.......................................................................................................................... 148
Summary ....................................................................................................................................... 150
■ Chapter 8: Modules and Packages for Code Reuse ...................................................................151
Imports for Reuse .......................................................................................................................... 151
Import Basics............................................................................................................................. 151
breakfast.py........................................................................................................................... 151
The Import Statement ................................................................................................................ 153
An Example Program...................................................................................................................... 153
greetings.py........................................................................................................................... 154
greet/__init__.py................................................................................................................... 154
greet/hello.py......................................................................................................................... 154
greet/people.py...................................................................................................................... 154
Trying Out the Example Code ..................................................................................................... 154
Types of Import Statements ........................................................................................................... 155
From Import Statements ............................................................................................................ 155
Relative Import Statements ........................................................................................................ 156
■ CONTENTS
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Aliasing Import Statements ........................................................................................................ 156
Hiding Module Names................................................................................................................ 157
Module Search Path, Compilation, and Loading.............................................................................. 157
Java Import Example ................................................................................................................. 157
Module Search Path and Loading............................................................................................... 158
Java Package Scanning ................................................................................................................. 158
How Jython Finds the Jars and Classes to Scan......................................................................... 159
Compilation ............................................................................................................................... 160
Python Modules and Packages versus Java Packages.................................................................... 160
sys.path..................................................................................................................................... 160
Naming Python Modules and Packages...................................................................................... 160
Proper Python Naming ............................................................................................................... 161
Advanced Import Manipulation....................................................................................................... 161
Import Hooks ............................................................................................................................. 161
sys.path_hooks.......................................................................................................................... 161
sys.meta_path........................................................................................................................... 162
Summary ....................................................................................................................................... 162
Part II: Using the Language .............................................................................................................163
■ Chapter 9: Scripting With Jython................................................................................................165
Getting the Arguments Passed to a Script ...................................................................................... 165
Searching for a File........................................................................................................................ 166
Manipulating Files.......................................................................................................................... 167
Making a Script a Module .............................................................................................................. 168
Parsing Commandline Options ....................................................................................................... 169
Compiling Java Source................................................................................................................... 170
Example Script: Builder.py ............................................................................................................. 170
HelloWorld.java .............................................................................................................................. 172
Summary ....................................................................................................................................... 173
■ Chapter 10: Jython and Java Integration ...................................................................................175
Using Java Within Jython Applications ........................................................................................... 175
Using Jython Within Java Applications ........................................................................................... 178
Object Factories......................................................................................................................... 179
One-to-One Jython Object Factories ...................................................................................... 179
Summary of One-to-One Object Factory................................................................................. 182
■ CONTENTS
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Making Use of a Loosely Coupled Object Factory ................................................................... 182
More Efficient Version of Loosely Coupled Object Factory....................................................... 186
Returning __doc__ Strings .................................................................................................... 188
Applying the Design to Different Object Types........................................................................ 190
JSR-223 .................................................................................................................................... 192
Utilizing PythonInterpreter.......................................................................................................... 193
Summary ....................................................................................................................................... 195
■ Chapter 11: Using Jython in an IDE ............................................................................................197
Eclipse........................................................................................................................................... 197
Installing PyDev ......................................................................................................................... 197
Minimal Configuration................................................................................................................ 198
Hello PyDev!: Creating Projects and Executing Modules ............................................................. 200
Passing Command-line Arguments and Customizing Execution.................................................. 201
Playing with the Editor ............................................................................................................... 202
A Bit of Structure: Packages, Modules, and Navigation............................................................... 204
Testing ...................................................................................................................................... 207
Adding Java Libraries to the Project ........................................................................................... 210
Debugging ..................................................................................................................................... 211
Conclusion about Eclipse ........................................................................................................... 213
Netbeans ....................................................................................................................................... 213
IDE Installation and Configuration................................................................................................... 214
Advanced Python Options............................................................................................................... 215
General Python Usage .................................................................................................................... 216
Standalone Jython Apps................................................................................................................. 216
Jython and Java Integrated Apps ................................................................................................... 221
Using a JAR or Java Project in Your Jython App ......................................................................... 221
Using Jython in Java.................................................................................................................. 222
The Netbeans Python Debugger..................................................................................................... 223
Other Netbeans Python Features .................................................................................................... 228
Summary ....................................................................................................................................... 228
■ Chapter 12: Databases and Jython: Object Relational Mapping and Using JDBC ....................231
ZxJDBC—Using Python’s DB API via JDBC..................................................................................... 231
Getting Started........................................................................................................................... 232
Connections............................................................................................................................... 233
ZxJDBC.lookup .......................................................................................................................... 237
■ CONTENTS
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Cursors.................................................................................................................................. 237
Creating and Executing Queries ............................................................................................. 240
Prepared Statements ................................................................................................................. 243
Resource Management .............................................................................................................. 243
Metadata ................................................................................................................................... 244
Data Manipulation Language and Data Definition Language ....................................................... 245
Calling Procedures................................................................................................................. 246
Customizing zxJDBC Calls...................................................................................................... 247
History ....................................................................................................................................... 249
Object Relational Mapping.............................................................................................................. 249
SqlAlchemy................................................................................................................................ 249
Installation ................................................................................................................................. 249
Using SqlAlchemy ...................................................................................................................... 250
Hibernate................................................................................................................................... 254
Entity Classes and Hibernate Configuration ................................................................................ 254
Jython Implementation Using the Java Entity Classes................................................................. 256
Summary ....................................................................................................................................... 261
Part III: Developing Applications with Jython ................................................................................263
■ Chapter 13: Simple Web Applications ........................................................................................265
Servlets ......................................................................................................................................... 265
Configuring Your Web Application for Jython Servlets................................................................. 266
Writing a Simple Servlet............................................................................................................. 266
Using JSP with Jython ............................................................................................................... 268
Configuring for JSP................................................................................................................ 269
Coding the Controller/View..................................................................................................... 269
Applets and Java Web Start ........................................................................................................... 272
Coding a Simple GUI-Based Web Application.............................................................................. 272
Object Factory Application Design.......................................................................................... 272
Distributing via Standalone JAR ................................................................................................. 276
WSGI and Modjy............................................................................................................................. 276
Running a Modjy Application in Glassfish ................................................................................... 277
Summary ....................................................................................................................................... 280
■ Chapter 14: Web Applications With Django................................................................................281
Getting Django ............................................................................................................................... 281
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A Quick Tour of Django .................................................................................................................. 282
Starting a Project (and an “App”) ............................................................................................... 283
Models....................................................................................................................................... 284
Bonus: The Admin...................................................................................................................... 287
Views and Templates................................................................................................................. 292
Reusing Templates Without “include”: Template Inheritance...................................................... 297
Forms ........................................................................................................................................ 300
Feeds......................................................................................................................................... 302
Comments ................................................................................................................................. 304
And More................................................................................................................................... 306
J2EE Deployment and Integration................................................................................................... 307
Deploying Your First Application................................................................................................. 308
Disabling PostgreSQL Logins ..................................................................................................... 308
A Note About WAR Files ............................................................................................................. 309
Extended Installation.................................................................................................................. 311
Connection Pooling With JavaEE ................................................................................................ 312
Dealing With Long-running Tasks .............................................................................................. 315
Thread Pools.............................................................................................................................. 315
Passing Messages Across Process Boundaries........................................................................... 318
Summary ....................................................................................................................................... 325
■ Chapter 15: Introduction to Pylons .............................................................................................327
A Guide for the Impatient ............................................................................................................... 327
A Note about Paste ........................................................................................................................ 329
Pylons MVC.................................................................................................................................... 329
An Interlude into Java’s Memory Model.......................................................................................... 330
Invoking the Pylons Shell ............................................................................................................... 331
request.GET ............................................................................................................................... 332
request.POST............................................................................................................................. 332
request.params.......................................................................................................................... 332
request.headers......................................................................................................................... 333
Context Variables and Application Globals ...................................................................................... 333
Routes ........................................................................................................................................... 333
Controllers and Templates ............................................................................................................. 334
Adding a JSON API......................................................................................................................... 340
Unit Testing, Functional Testing, and Logging ................................................................................ 341
■ CONTENTS
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Deployment into a Servlet Container .............................................................................................. 346
Summary ....................................................................................................................................... 346
■ Chapter 16: GUI Applications ......................................................................................................347
Summary ....................................................................................................................................... 357
■ Chapter 17: Deployment Targets ................................................................................................359
Application Servers ........................................................................................................................ 359
Tomcat ...................................................................................................................................... 360
Deploying Web Start .............................................................................................................. 360
Deploying a WAR or Exploded Directory Application ............................................................... 360
Glassfish.................................................................................................................................... 361
Deploying Web Start .............................................................................................................. 361
WAR File and Exploded Directory Deployment........................................................................ 362
Glassfish v3 Django Deployment............................................................................................ 362
Other Java Application Servers .................................................................................................. 362
Google App Engine......................................................................................................................... 362
Starting With an SDK Demo ....................................................................................................... 363
Deploying to the Cloud............................................................................................................... 363
Working With a Project............................................................................................................... 364
Object Factories with App Engine............................................................................................... 365
Using PyServlet Mapping ........................................................................................................... 365
Example Jython Servlet Application for App Engine .................................................................... 366
Using Eclipse ............................................................................................................................. 369
Deploy Modjy to GAE.................................................................................................................. 370
Java Store...................................................................................................................................... 370
Deploying a Single JAR .............................................................................................................. 371
Mobile............................................................................................................................................ 375
Summary ....................................................................................................................................... 375
Part IV: Strategy and Technique......................................................................................................377
■ Chapter 18: Testing and Continuous Integration .......................................................................379
Python Testing Tools...................................................................................................................... 379
UnitTest ..................................................................................................................................... 379
Doctests .................................................................................................................................... 384
A Complete Example.................................................................................................................. 388
Nose .......................................................................................................................................... 395
■ CONTENTS
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Integration with Java?................................................................................................................ 400
Continuous Integration ................................................................................................................... 401
Hudson ...................................................................................................................................... 401
Getting Hudson .......................................................................................................................... 401
Installing the Jython Plug-in....................................................................................................... 402
Creating a Hudson Job for a Jython Project................................................................................ 403
Using Nose on Hudson ............................................................................................................... 407
Summary ....................................................................................................................................... 410
■ Chapter 19: Concurrency.............................................................................................................413
Java or Python APIs?...................................................................................................................... 414
Working With Threads.................................................................................................................... 414
Thread Locals ................................................................................................................................ 416
No Global Interpreter Lock.............................................................................................................. 417
Module Import Lock ....................................................................................................................... 417
Working With Tasks ....................................................................................................................... 418
Thread Safety ................................................................................................................................ 422
Synchronization ......................................................................................................................... 423
Deadlocks.................................................................................................................................. 426
Other Synchronization Objects ................................................................................................... 427
Atomic Operations ..................................................................................................................... 431
Thread Confinement .................................................................................................................. 432
Python Memory Model ................................................................................................................... 433
Interruption .................................................................................................................................... 433
Summary ....................................................................................................................................... 436
■ Appendix A: Using Other Tools with Jython ...............................................................................437
The Jython Registry ....................................................................................................................... 437
Registry Properties..................................................................................................................... 437
python.cachedir..................................................................................................................... 437
python.verbose ...................................................................................................................... 437
python.security.respectJavaAccessibility................................................................................ 438
python.jythonc.compiler......................................................................................................... 438
python.jythonc.classpath ....................................................................................................... 438
python.jythonc.compileropts .................................................................................................. 438
python.console ...................................................................................................................... 438
python.console.readlinelib ..................................................................................................... 438
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Finding the Registry File............................................................................................................. 438
Setuptools...................................................................................................................................... 438
Virtualenv....................................................................................................................................... 442
■ Appendix B: Jython Cookbook ....................................................................................................445
Logging.......................................................................................................................................... 445
Using log4j with Jython, Josh Juneau ........................................................................................ 445
Setting Up Your Environment ................................................................................................. 445
Using log4j in a Jython Application......................................................................................... 446
Working with Spreadsheets............................................................................................................ 447
Creating and Reading Spreadsheets Using Apache Poi............................................................... 447
Create Spreadsheet ............................................................................................................... 447
Read an Excel File.................................................................................................................. 449
Jython and XML ............................................................................................................................. 450
Writing and Parsing RSS with ROME, Josh Juneau..................................................................... 450
Setting up the CLASSPATH..................................................................................................... 450
Parsing Feeds........................................................................................................................ 450
Creating Feeds....................................................................................................................... 451
Summary............................................................................................................................... 454
Working with CLASSPATH.............................................................................................................. 454
Using the CLASSPATH, Steve Langer.......................................................................................... 454
What to Do?........................................................................................................................... 454
Method .................................................................................................................................. 454
Summary............................................................................................................................... 456
Ant................................................................................................................................................. 456
Writing Ant Tasks with Jython, Ed Takema................................................................................. 456
Writing Custom Ant Tasks...................................................................................................... 457
Setup Development Environment ........................................................................................... 457
SimpleTask Jython Class ....................................................................................................... 457
Compiling Jython Code to a Jar.............................................................................................. 458
Build.XML File to Use the Task............................................................................................... 458
A Task Container Task ........................................................................................................... 458
Build.XML File to Use the TaskContainer ................................................................................ 459
Things to Look Out For........................................................................................................... 460
Summary............................................................................................................................... 461
Developing Django Web Apps......................................................................................................... 461
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Using Django in Netbeans, Josh Juneau..................................................................................... 461
■ Appendix C: Built-in Functions ...................................................................................................463
Constructor Functions .................................................................................................................... 463
bool([x]) ..................................................................................................................................... 463
chr(i).......................................................................................................................................... 463
complex([real[, imag]])............................................................................................................... 464
dict([arg])................................................................................................................................... 464
file(filename[, mode[, bufsize]]).................................................................................................. 464
float([x]) ..................................................................................................................................... 464
frozenset([iterable]).................................................................................................................... 464
int([x[, radix]]) ............................................................................................................................ 464
iter(o[, sentinel])......................................................................................................................... 465
list([iterable]).............................................................................................................................. 465
object() ...................................................................................................................................... 465
open(filename[, mode[, bufsize]])............................................................................................... 465
range([start,] stop[, step])........................................................................................................... 466
set([iterable]) ............................................................................................................................. 466
slice([start,] stop[, step]) ............................................................................................................ 466
str([object]) ................................................................................................................................ 467
tuple([iterable]) .......................................................................................................................... 467
type(name, bases, dict).............................................................................................................. 467
unichr(i) ..................................................................................................................................... 467
unicode([object[, encoding [, errors]]])........................................................................................ 467
xrange([start,] stop[, step])......................................................................................................... 468
Math Built-in Functions .................................................................................................................. 468
abs(x)......................................................................................................................................... 468
cmp(x, y).................................................................................................................................... 468
divmod(a, b)............................................................................................................................... 468
pow(x, y[, z]) .............................................................................................................................. 468
round(x[, n]) ............................................................................................................................... 469
Functions on Iterables.................................................................................................................... 469
all(iterable)................................................................................................................................. 469
any(iterable)............................................................................................................................... 469
enumerate(sequence[, start=0])................................................................................................. 469
filter(function, iterable)............................................................................................................... 469
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map(function, iterable, ...).......................................................................................................... 470
max(iterable[, key])or max([, arg, ...][, key])................................................................................ 470
min(iterable[, key]) or min([, arg, ...][, key]) ................................................................................ 470
reduce(function, iterable[, initializer]) ......................................................................................... 470
reversed(seq)............................................................................................................................. 470
sorted(iterable[, cmp[, key[, reverse]]])....................................................................................... 470
sum(iterable[, start=0]).............................................................................................................. 471
zip([iterable, ...])......................................................................................................................... 471
Conversion Functions..................................................................................................................... 472
hex(x)......................................................................................................................................... 472
long([x[, radix]]).......................................................................................................................... 472
oct(x) ......................................................................................................................................... 472
ord(c)......................................................................................................................................... 472
Functions for Working with Code.................................................................................................... 472
classmethod(function)................................................................................................................ 472
compile(source, filename, mode[, flags[, dont_inherit]]) ............................................................. 473
eval(expression[, globals[, locals]])............................................................................................. 474
execfile(filename[, globals[, locals]]) .......................................................................................... 474
property([fget[, fset[, fdel[, doc]]]]) ............................................................................................. 475
staticmethod(function) ............................................................................................................... 476
super(type[, object-or-type]) ...................................................................................................... 476
Input Functions .............................................................................................................................. 477
input([prompt])........................................................................................................................... 477
raw_input([prompt])................................................................................................................... 477
Functions for Working with Modules and Objects ........................................................................... 478
callable(object)........................................................................................................................... 478
delattr(object, name).................................................................................................................. 478
dir([object]) ................................................................................................................................ 478
getattr(object, name[, default])................................................................................................... 479
globals()..................................................................................................................................... 479
hasattr(object, name)................................................................................................................. 479
hash(object)............................................................................................................................... 480
help([object]).............................................................................................................................. 480
id(object).................................................................................................................................... 480
isinstance(object, classinfo) ....................................................................................................... 480
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issubclass(class, classinfo) ........................................................................................................ 480
len(s) ......................................................................................................................................... 480
locals()....................................................................................................................................... 481
reload(module)........................................................................................................................... 481
repr(object) ................................................................................................................................ 482
setattr(object, name, value)........................................................................................................ 482
type(object)................................................................................................................................ 482
vars([object]).............................................................................................................................. 482
__import__(name[, globals[, locals[, fromlist[, level]]]]).............................................................. 483
Index................................................................................................................................................485