用 Java 压缩文件

首先,与此相关的类是java.util.zip.ZipOutputStream,其构造函数为ZipOutputStream(OutputStream out)。

下面以一个实例来说明如何用java完成对文件的压缩。

 

package ziptest;

import java.io.*;
import java.util.zip.*;

public class Zip{
	static final int BUFFER = 2048;
	static boolean flag = false;
	public static void main(String[] args) throws IOException{
		File file = new File("D:/TT");
		boolean b1 = file.exists();
		if(!b1)
			throw new RuntimeException("The Dir is not exist!");
		ZipSubdirectory(file);
		//FileInputStream file1 = new FileInputStream(ZipSubdirectory(file));				//这两段话是为何...
		//System.out.println(file1.toString());												
	}
	public static File ZipSubdirectory(File myDir) throws IOException{
		BufferedInputStream origin = null;
		File zipFile = new File("D:/" + myDir.getName() + ".zip");							//此处为生成的zip文件的文件名
		//File zipFile = new File("D:/" + "aaa" + ".zip");									//这样就将生成的zip文件改名了
		System.out.println("Creat: D:/" + myDir.getName() + ".zip");						//调试用
		FileOutputStream fos = new FileOutputStream(zipFile);
		ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(fos,BUFFER));
		//ZipOutputStream out = new ZipOutputStream(fos);									//这么写也行,只是就不用缓冲文件了
		File dirContents[] = myDir.listFiles();
		File tempFile = null;
		try{
			for(int i = 0;i < dirContents.length;i++){
				if(dirContents[i].isDirectory()){
					tempFile = ZipSubdirectory(dirContents[i]);								//这里就是个递归,因为是递归,所以子目录也被单独压缩了,当然,子目录的子目录也是
					flag = true;															//需要注意的是,这里进入递归之后,返回的tempFile是*.zip
				}
				else{
					tempFile = dirContents[i];
					flag = false;
				}
				System.out.println("Compress file:" + tempFile.getName());					//打印压缩内容信息,如果递归了,那么就压缩一个目录(也就是将.zip作为一个内容放入父目录)
				FileInputStream fis = new FileInputStream(tempFile);
				origin = new BufferedInputStream(fis,BUFFER);
				ZipEntry entry = new ZipEntry(tempFile.getName());							//为被读取的文件创建压缩条目,否则只有目录,目录内无文件
				byte[] data = new byte[BUFFER];
				int count;
				out.putNextEntry(entry);													//在向ZIP输出流写入数据之前，必须首先使用out.putNextEntry(entry); 方法安置压缩条目对象
				while((count = origin.read(data,0,BUFFER)) != -1){
					out.write(data,0,count);
				}
				origin.close();
				if(flag == true){															//这段语句删除tempFile目录失败,可能是没有关闭此文件的流
					flag = tempFile.delete();												//如果是目录,会在D:/下又新建一个.zip,所以要删除
					System.out.println("Delete file:"+tempFile.getName()+flag);
				}
				//origin.close();															//关闭缓冲流要是放在这,会导致上面这段语句执行失败
			}
			out.close();
		}catch(Exception e){
			System.out.println(e);
		}
		return zipFile;
	}
}

    这里对以上程序做个简要说明:

首先里面最重要的主体,ZipSubdirectory()方法是一个带返回值(返回类型为File，返回zipFile，具体作用看递归内容)的带参数(参数类型也为File)的方法,其中使用了递归来完成对子目录的压缩.

public BufferedOutputStream(OutputStream out,int size)是一个字节缓冲输出流,该方法实现创建给定大小输出缓冲区的缓冲字节输出流.

public ZipEntry(String name)name为指定的数据项名.

在向ZIP输出流写入数据之前，必须首先使用out.putNextEntry(entry) 方法安置压缩条目对象

 

解压缩代码

package test4;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;

import java.io.FileInputStream;
import java.io.FileOutputStream;

import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.util.zip.ZipOutputStream;
//import org.apache.tools.zip.*;

public class Test {


	public static void main(String[] args) {
		readFileAndWriteZip();
		unZipFile();
	}

	public static void unZipFile() {
	try{
		//int BUFFER = 1024;
		int BUFFER = 1024;
		BufferedOutputStream dest = null;
        FileInputStream fis = new FileInputStream("D:/2M.zip");
        ZipInputStream zis = new ZipInputStream(new BufferedInputStream(fis));
        //ZipFile zis = new ZipFile(new BufferedInputStream(fis));
        ZipEntry entry;
        while ((entry = zis.getNextEntry()) != null) {
            System.out.println("Extracting: " + entry);
            int count;
           // byte data[] = new byte[1024];
            byte data[] = new byte[1024];
            FileOutputStream fos = new  FileOutputStream("D:/Ta/"+entry.getName());
            dest = new BufferedOutputStream(fos, BUFFER);
            while ((count = zis.read(data, 0, BUFFER)) != -1) {
                dest.write(data, 0, count);
            }
            dest.flush();
            dest.close();
        }
        zis.close();
    } catch (Exception e) {
        e.printStackTrace();
    }

	}

	public static void readFileAndWriteZip() {

		try {
			 
		} catch (Exception ex){
			System.err.println(ex.toString());
		}
	}

	 

}