Java字符串压缩和解压缩代码

Java字符串压缩和解压缩代码

字符串压缩需要字符串达到一定长度后才有效果，如果只是很短的字符串压缩后的长度可能比压缩前还要长

代码转自：http://gllwhq.iteye.com/

package com.util;

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 ZipUtil {

  // 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："+ZipUtil.compress(str).length());  
	  
    System.out.println("解压缩："+ZipUtil.uncompress(ZipUtil.compress(str)));
  }

}

运行结果:

原长度：104&nbsp

压缩后：95