zk+jsp实现登录、注册、修改密码小例子

【核心代码】

package sample.zk;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.HashMap;

import javax.servlet.ServletContext;
import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.struts.webapp.example.memory.MemoryUserDatabase;

public final class MemoryDatabasePlugIn implements ServletContextListener {

private MemoryUserDatabase database = null;
private Log log = LogFactory.getLog(this.getClass());
private String pathname = "/WEB-INF/database.xml";

public String getPathname() {
return (this.pathname);
}

public void setPathname(String pathname) {
this.pathname = pathname;
}

public void contextDestroyed(ServletContextEvent sec) {
log.info("Finalizing memory database plug in");

        if (database != null) {
            try {
                database.close();
            } catch (Exception e) {
                log.error("Closing memory database", e);
            }
        }

sec.getServletContext().removeAttribute("database");
    database = null;
    database = null;
}

public void contextInitialized(ServletContextEvent sce) {
log
.info("Initializing memory database plug in from '" pathname
"'");
database = new MemoryUserDatabase();
try {
setPathname(sce.getServletContext().getInitParameter("pathname"));
String path = calculatePath(sce.getServletContext());
if (log.isDebugEnabled()) {
log.debug(" Loading database from '" path "'");
}
database.setPathname(path);
database.open();
} catch (Exception e) {
log.error("Opening memory database", e);
}

sce.getServletContext().setAttribute("database",database);
setupCache(sce.getServletContext());
}


private String calculatePath(ServletContext sc) throws Exception {

        // Can we access the database via file I/O?
        String path = sc.getRealPath(pathname);
        if (path != null) {
            return (path);
        }

        // Does a copy of this file already exist in our temporary directory
        File dir = (File)
            sc.getAttribute("javax.servlet.context.tempdir");
        File file = new File(dir, "struts-example-database.xml");
        if (file.exists()) {
            return (file.getAbsolutePath());
        }

        // Copy the static resource to a temporary file and return its path
        InputStream is = sc.getResourceAsStream(pathname);
        BufferedInputStream bis = new BufferedInputStream(is, 1024);
        FileOutputStream os =
            new FileOutputStream(file);
        BufferedOutputStream bos = new BufferedOutputStream(os, 1024);
        byte buffer[] = new byte[1024];
        while (true) {
            int n = bis.read(buffer);
            if (n <= 0) {
                break;
            }
            bos.write(buffer, 0, n);
        }
        bos.close();
        bis.close();
        return (file.getAbsolutePath());

    }

protected void setupCache(ServletContext sc) {

        // Set up list of server types under "serverTypes"
        HashMap serverTypes = new HashMap();
        serverTypes.put("imap","IMAP Protocol");
        serverTypes.put("pop3","POP3 Protocol");
        sc.setAttribute("serverTypes", serverTypes);

    }
}