使用GZIP压缩的方式向客户端传输响应数据

1， 工具类：测试客户端是否支持GZIP编码压缩方式 & 获得支持GZIP的PrintWriter对象

package freebsd;

import java.io.IOException;

import java.io.PrintWriter;

import java.util.zip.GZIPOutputStream;

import javax.servlet.ServletOutputStream;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

public class Utilities {

/*

* 测试客户端浏览器是否支持gzip的编码方式

*/

public static boolean isSurpported(HttpServletRequest request)

{

String encodingString = request.getHeader("Accept-Encoding");

return (encodingString!=null) && (encodingString.indexOf("gzip")!=-1);

}

/*

* 取得一个压缩的PrintWriter

*/

public static PrintWriter getWriter(HttpServletResponse response) throws IOException

{

ServletOutputStream sos = response.getOutputStream();

GZIPOutputStream gzipos = new GZIPOutputStream(sos);

return new PrintWriter(gzipos);

}

}

2，Servlet类，产生一个长字符串，然后在html页面中请求该servlet:

import freebsd.*;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

* Servlet implementation class ServletGzip

*/

public class ServletGzip extends HttpServlet {

private static final long serialVersionUID = 1L;



/**

* @see HttpServlet#HttpServlet()

*/

public ServletGzip() {

super();

// TODO Auto-generated constructor stub

}

/**

* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

*/

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

doPost(request, response);

}

/**

* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

*/

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

response.setContentType("text/html");

response.setStatus(response.SC_OK);

PrintWriter out;

if(Utilities.isSurpported(request))

{

out = Utilities.getWriter(response);

//协议： 通知客户端使用gzip这种压缩方式而不是其它的，如compress

response.setHeader("Content-Encoding", "gzip")；

}else {

out = response.getWriter();

}

StringBuilder sBuilder = new StringBuilder();

for(int i=0; i!=5000; ++i)

{

sBuilder.append("Printing the long string... ...!");

}

out.println(sBuilder);

out.close();

}

}