对字符串进行压缩，压缩成gzip流，效果好不错

package test;import java.io.ByteArrayInputStream;import java.io.ByteArrayOutputStream;import java.io.IOException;import java.util.zip.GZIPInputStream;import java.util.zip.GZIPOutputStream;public class testZip { // 压缩 public static byte[] compress(String str) throws IOException { if (str == null || str.length() == 0) { return null; } ByteArrayOutputStream out = new ByteArrayOutputStream(); GZIPOutputStream gzip = new GZIPOutputStream(out); gzip.write(str.getBytes("UTF-8")); gzip.close(); return out.toByteArray();  } // 解压缩 public static byte[] uncompress(byte[] str) throws IOException { if (str == null || str.length == 0) { return null; } ByteArrayOutputStream out = new ByteArrayOutputStream(); ByteArrayInputStream in = new ByteArrayInputStream(str); GZIPInputStream gunzip = new GZIPInputStream(in); byte[] buffer = new byte[256]; int n; while ((n = gunzip.read(buffer)) >= 0) { out.write(buffer, 0, n); } return out.toByteArray(); } public static void main(String[] args) throws IOException { StringBuffer bf = new StringBuffer(); bf.append("234235423sdfgsatg43qr4rfsetuyw45t3wfeszdfvm 0394tivq0m234rfqa2,-r0kaw03 5jhtqca9203rjm0,qva9tj0qa3wj445"); String data= bf.toString(); System.out.println("压缩前内容:" + data); System.out.println("压缩前大小:" + data.length()); String outdata = new String(testZip.compress(data)); System.out.println("压缩后内容:" + outdata); System.out.println("压缩后大小:" + outdata.length()); String undata = null; undata = new String(testZip.uncompress(outdata.getBytes("UTF-8"))); System.out.println("解缩后内容:" + undata); System.out.println("解缩后大小:" + undata.length()); }}

压缩只有就得到byte[]的字节流，数据大小对重复数据大的要小很多，我测试时使用了2000个MD5值，从6K压缩到1以下，效果还不错