package com.yangxiaozuo.util;

import java.io.ByteArrayOutputStream;  
import java.io.IOException;  
import java.util.zip.Deflater;  
import java.util.zip.Inflater;

/**
* ZLib压缩工具
*  
* @author 梁栋
* @version 1.0
* @since 1.0
*/
public abstract class ZLibUtils {

/**
     * 压缩
     *  
     * @param data
     *            待压缩数据
     * @return byte[] 压缩后的数据
     */
    public static byte[] compress(byte[] data) {  
        byte[] output = new byte[0];

Deflater compresser = new Deflater();

compresser.reset();  
        compresser.setInput(data);  
        compresser.finish();  
        ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length);  
        try {  
            byte[] buf = new byte[1024];  
            while (!compresser.finished()) {  
                int i = compresser.deflate(buf);  
                bos.write(buf, 0, i);  
            }  
            output = bos.toByteArray();  
        } catch (Exception e) {  
            output = data;  
            e.printStackTrace();  
        } finally {  
            try {  
                bos.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }  
        compresser.end();  
        return output;  
    }

/**
     * 解压缩
     *  
     * @param data
     *            待压缩的数据
     * @return byte[] 解压缩后的数据
     */
    public static byte[] decompress(byte[] data) {  
        byte[] output = new byte[0];

Inflater decompresser = new Inflater();  
        decompresser.reset();  
        decompresser.setInput(data);

ByteArrayOutputStream o = new ByteArrayOutputStream(data.length);  
        try {  
            byte[] buf = new byte[1024];  
            while (!decompresser.finished()) {  
                int i = decompresser.inflate(buf);  
                o.write(buf, 0, i);  
            }  
            output = o.toByteArray();  
        } catch (Exception e) {  
            output = data;  
            e.printStackTrace();  
        } finally {  
            try {  
                o.close();  
            } catch (IOException e) {  
                e.printStackTrace();  
            }  
        }

decompresser.end();  
        return output;  
    }  
   
   
    public static void main(String[] args){
    String inputStr = "snowolf@zlex.org;dongliang@zlex.org;zlex.dongliang@zl";  
         System.err.println("输入字符串:\t" + inputStr);  
         byte[] input = inputStr.getBytes();  
         System.err.println("输入字节长度:\t" + input.length);  
  
         byte[] data = ZLibUtils.compress(input);  
         System.err.println("压缩后字节长度:\t" + data.length);  
  
         byte[] output = ZLibUtils.decompress(data);  
         System.err.println("解压缩后字节长度:\t" + output.length);  
         String outputStr = new String(output);  
         System.err.println("输出字符串:\t" + outputStr);  
    }
}