JAVA字符串的GZIP压缩解压缩

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)));   
  }   
 
}