JAVA中压缩与解压缩

以压缩Zip文件为例。主要是通过ZipOutputStream类实现。

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

//压缩一个文件
//压缩一个文件夹

public class Hello
{
    public static void main(String[] args)throws Exception
    {
        final int BUFFER_LENGTH = 1024*1024;
        byte[] buffer = new byte[BUFFER_LENGTH];
        File sourceFile = new File("D:\\AsmTools");
        File zipFile = new File("d:\\"+getFileName(sourceFile.getName())+".zip");
        InputStream is = null;
        ZipOutputStream zipOut = new ZipOutputStream(new FileOutputStream(zipFile));
        int len = 0;
        File[] files = sourceFile.listFiles();
        for(File file : files)
        {
            is = new FileInputStream(file);
            zipOut.putNextEntry(new ZipEntry(file.getName()));
            while((len= is.read(buffer,0,BUFFER_LENGTH))>0)
            {
                zipOut.write(buffer,0,len);
            }

            is.close();
        }
        zipOut.close();
    }

    public static String getFileName(String fileName)
    {
        String retVal;
        int lastIndex = fileName.lastIndexOf(".");
        if(lastIndex < 0)
            retVal = fileName;
        else
            retVal = fileName.substring(0,lastIndex);
        return retVal;
    }
}

解压缩主要使用ZipFile类和ZipOutputStream类。

ZipOutputStream 获取压缩文件中的每个ZipEntry，然后ZipFile通过ZipEntry拿到输入流。

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

//压缩一个文件
//压缩一个文件夹

public class Hello
{
    public static void main(String[] args)throws Exception
    {
        final int BUFFER_LENGTH = 1024*1024;
        File sourceZipFile = new File("d:\\AsmTools.zip");
        File unzippedFolder = new File("d:\\"+getFileName(sourceZipFile.getName()));
        ZipInputStream zipInput = new ZipInputStream(new FileInputStream(sourceZipFile));
        ZipFile zipFile = new ZipFile(sourceZipFile);
        ZipEntry tempZipEntry = null;
        InputStream is = null;
        OutputStream os = null;
        byte[] buffer = new byte[BUFFER_LENGTH];
        int bytesReaded = 0;
        if(!unzippedFolder.exists())
        {
            unzippedFolder.mkdir();
        }

        while((tempZipEntry = zipInput.getNextEntry()) != null)
        {
            is = zipFile.getInputStream(tempZipEntry);
            os = new FileOutputStream("d:\\" + unzippedFolder.getName()+"\\"+tempZipEntry.getName());
            System.out.println("正在解压:" + tempZipEntry.getName());
            while((bytesReaded = is.read(buffer,0,BUFFER_LENGTH))>0)
            {
                os.write(buffer,0,bytesReaded);
            }

            is.close();
            os.close();
        }

        zipInput.close();
    }

    public static String getFileName(String fileName)
    {
        String retVal;
        int lastIndex = fileName.lastIndexOf(".");
        if(lastIndex < 0)
            retVal = fileName;
        else
            retVal = fileName.substring(0,lastIndex);

        return retVal;
    }
}