// 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)));

     }

 }