package com.gzip;

import java.io.ByteArrayInputStream;

import java.io.ByteArrayOutputStream;

import java.io.IOException;

import java.util.zip.GZIPInputStream;

import java.util.zip.GZIPOutputStream;

// 将一个字符串按照zip方式压缩和解压缩

public class ZipUtil2 {   

 // 压缩

 public static String compress(String str) throws IOException {

    if (str == null || str.length() == 0) {

     return str;

   }

    ByteArrayOutputStream out = new ByteArrayOutputStream();

   GZIPOutputStream gzip = new GZIPOutputStream(out);

    gzip.write(str.getBytes());

    gzip.close();

   return out.toString("ISO-8859-1");

  }   

  // 解压缩

 public static String uncompress(String str) throws IOException {

    if (str == null || str.length() == 0) {

      return str;

  }

   ByteArrayOutputStream out = new ByteArrayOutputStream();

   ByteArrayInputStream in = new ByteArrayInputStream(str

        .getBytes("ISO-8859-1"));

    GZIPInputStream gunzip = new GZIPInputStream(in);

    byte[] buffer = new byte[256];

    int n;

   while ((n = gunzip.read(buffer))>= 0) {

    out.write(buffer, 0, n);

    }

    // toString()使用平台默认编码，也可以显式的指定如toString("GBK")

    return out.toString();

  }   

  // 测试方法

  public static void main(String[] args) throws IOException {   

      //测试字符串

     String str="%5B%7B%22lastUpdateTime%22%3A%222011-10-28+9%3A39%3A41%22%2C%22smsList%22%3A%5B%7B%22liveState%22%3A%221";   

      System.out.println("原长度："+str.length());     

      System.out.println("压缩后："+ZipUtil2.compress(str).length());     

    System.out.println("解压缩："+ZipUtil2.uncompress(ZipUtil2.compress(str)));

  }   

}