java实现gzip

package com.test;

import java.io.IOException;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import .FilenameUtils;
import org.apache.commons.lang.StringUtils;

/**
 * 
 * @author LiMing
 *
 */
@WebFilter("/MyFilter")
public class MyFilter implements Filter {


    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest)req;  
        HttpServletResponse response = (HttpServletResponse)res; 
        //获取请求路径
        String uri = request.getRequestURI();  
        //获取请求后缀 .js  .css  .do 。。。
        String ext = FilenameUtils.getExtension(uri);  

        try{  
            //设置想用头信息      
            //关于相应头属性意思可以看博客： http://blog.csdn.net/qq_36291682/article/details/71860958
            response.setHeader("Pragma", "No-cache");  
            response.setHeader("Cache-Control", "no-cache");  
            response.setDateHeader("Expires", -1);  
            //设置相应编码信息
            request.setCharacterEncoding("UTF-8");  
            response.setCharacterEncoding("UTF-8");  
            response.setHeader("renderer", "webkit");   
            response.setHeader("viewport", "width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0 user-scalable=no");   

            if(isGZipEncoding(request)){  
                //需要过滤的扩展名：.htm,.html,.jsp,.js,.ajax,.css  
                String gzippPattern=",.htm,.html,.jsp,.js,.ajax,.css,.do,";  
                //如果是需要gzip压缩的路径
                if(StringUtils.indexOf(gzippPattern, ",."+ext+",")!=-1){ 
                    //把response转换成gzipResponse
                    BufferedResponse gzipResponse = new BufferedResponse(response);  
                    //doFilter 之后还会等待ServletOutputStream 返回数据
                    chain.doFilter(request, gzipResponse);  
                    //获取源数据
                    byte[] srcData = gzipResponse.getResponseData(); 
                    //输出数据
                    byte[] outData = null;  
                    //如果源数据的长度大于512
                    if(srcData.length > 512){ 
                        //gzip
                        byte[] gzipData = ZipUtil.gZip(srcData);  
                        response.addHeader("Content-Encoding", "gzip");  
                        response.setContentLength(gzipData.length);  
                        //
                        outData = gzipData;  
                    } else {  
                        outData = srcData;  
                    }  
                    ServletOutputStream output = response.getOutputStream();  
                    output.write(outData);  
                    output.flush();  
                    output.close();
                } else {  
                    chain.doFilter(request, response);  
                }  
                return;  
            }  

            chain.doFilter(request, response);  
        }catch(Exception e){  
          e.printStackTrace();
        }finally{  

        }  
    }

    /**
     * 判断浏览器是不是支持gzip
     *@author LiMing  E-mail:1151143484@
     *2017年5月13日  下午3:46:33
     */
    private boolean isGZipEncoding(HttpServletRequest request){  
      boolean flag=false;  
      String encoding=request.getHeader("Accept-Encoding");  
      //gzip, deflate, sdch
      if(encoding.indexOf("gzip")!=-1){  
        flag=true;  
      }  
      return flag;  
    }   

    public void destroy() {
    }
    public void init(FilterConfig fConfig) throws ServletException {
    }
}




zipUtil.java

package com.test;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.zip.GZIPOutputStream;

public class ZipUtil {
    /**
     * 压缩GZip
     * 
     * @param data
     * @return
     * @throws CustomizeException
     */
    public static byte[] gZip(byte[] data) {
        byte[] b = null;
        ByteArrayOutputStream bos = null;
        GZIPOutputStream gzip = null;
        try {
            bos = new ByteArrayOutputStream();
            gzip = new GZIPOutputStream(bos);
            gzip.write(data);
            gzip.finish();
            b = bos.toByteArray();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                bos.close();
                gzip.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return b;
    }
}

 

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