java实现文件分割与合并 类示例源码

【核心代码】

package cn.part.com;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class LargeMappedFiles {
	public static void splitFile(File file, int size,String path) throws Exception {
		if (size <= 0) {
			size = 1024;
		}
		if (!file.isFile()) {
			throw new Exception("file not exists"   path file.getName());
		}
		String filename = path file.getName();
		File filetmp = new File(filename   "_"   0   ".zip");
		if (filetmp.isFile()) {
			throw new Exception("file exists"   path file.getName());
		}

		byte[] buf = new byte[1024 * 10];
		FileInputStream fis = new FileInputStream(file);
		int readsize = 0;
		int pos = 0;
		int k = 0;
		int m = -1;
		File fileout = null;
		FileOutputStream fos = null;
		while ((readsize = fis.read(buf, 0, buf.length)) > 0) {

			if (k != m) {
				if (fos != null) {
					fos.close();
					fos = null;
				}
				m = k;
				fileout = new File(filename   "_"   k   ".zip");
				fos = new FileOutputStream(fileout);
			}
			fos.write(buf, 0, readsize);
			fos.flush();
			pos  = readsize;
			if (pos > size * (k   1)) {
				k  ;
			}
		}
		if (fos != null) {
			fos.close();
			fos = null;
		}
		fis.close();
	}

	// 合并文件
	public static void combination(File file) throws Exception {
		String filename = file.getAbsolutePath();
		File fileout = new File(filename);

		if (fileout.isFile()) {
			throw new Exception("file exists"   fileout.getAbsolutePath());
		}
		FileOutputStream fos = new FileOutputStream(fileout);
		int k = 0;
		File filein = null;
		FileInputStream fis = null;
		byte[] buf = new byte[1024 * 10];
		while (true) {
			if (fis != null) {
				fis.close();
				fis = null;
			}
			filein = new File(filename   "_"   k   ".zip");
			if (!filein.isFile()) {
				break;
			}
			fis = new FileInputStream(filein);
			int readsize = 0;
			while ((readsize = fis.read(buf, 0, buf.length)) > 0) {
				fos.write(buf, 0, readsize);
				fos.flush();
			}
			k  ;
		}
		if (fis != null) {
			fis.close();
			fis = null;
		}
		fos.close();
		
	}

	public static void main(String[] args) throws Exception {
		//splitFile(new File("E:\\downlaod\\c\\inventory.local.debug.zip"),4922765,"E:\\downlaod\\");
		combination(new File("E:\\downlaod\\inventory.local.debug.zip"));
	}
}