package com.bcxin.survey.utils;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.zip.GZIPInputStream;
import java.util.zip.GZIPOutputStream;

/**
 * @author aluo
 * String压缩/解压
 */
public class StringCompress {

	/**
	 * 压缩字符串
	 * 
	 * @param str
	 *            压缩的字符串
	 * @return 压缩后的字符串
	 */
	public static String compress(String str) {

		if (str == null || str.length() == 0) {   
		      return str;   
		}   
	    ByteArrayOutputStream out = new ByteArrayOutputStream();   
	    GZIPOutputStream gzip;
		try {
			gzip = new GZIPOutputStream(out);
			gzip.write(str.getBytes());   
		    gzip.close();   
		    return out.toString("ISO-8859-1");  
		} catch (IOException e) {
			e.printStackTrace();
		}
		return str;
	}

	/**
	 * 解压缩字符串
	 * 
	 * @param str
	 *            解压缩的字符串
	 * @return 解压后的字符串
	 */
	public static String decompress(String str){

		if (str == null || str.length() == 0) {   
		      return str;   
	    }   
	    ByteArrayOutputStream out = new ByteArrayOutputStream();   
	    ByteArrayInputStream in;
		try {
			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(); 
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return "";
	    
	}

	
	public static void main(String[] args) throws IOException {
		String a = "我哎祖国";
		String c = compress(a);
		System.out.println(decompress(c));
	}
}