用户向代理服务器发送请求，代理服务器从后端服务器上获取文件，并返回给用户
web.xml:
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<servlet>
<servlet-name>BigFile</servlet-name>
<servlet-class>cn.ac.dsp.servlet.BigFile</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>BigFile</servlet-name>
<url-pattern>*.ts</url-pattern>
</servlet-mapping>
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servlet:
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package cn.ac.dsp.servlet;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.io.StringWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.params.CoreProtocolPNames;
import org.apache.log4j.Logger;
import cn.ac.dsp.common.Constant;
import cn.ac.dsp.common.SystemParameters;
/**
* 给静态大文件提供服务的servlet
*/
public class BigFile extends HttpServlet {
private static final long serialVersionUID = 1L;
private static final Logger log = Logger.getLogger(BigFile.class);
/**
* @see HttpServlet#HttpServlet()
*/
public BigFile() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
log.info("request for bigfile");
long startTime = System.nanoTime();
String requestUrl = request.getRequestURI();
//请求的文件名
String filename = requestUrl.substring(requestUrl.lastIndexOf("/"));
HttpClient httpClient = new DefaultHttpClient();
httpClient.getParams().setParameter(CoreConnectionPNames.CONNECTION_TIMEOUT, Constant.HttpConnTimeOut);
httpClient.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, Constant.SoConnTimeOut);
httpClient.getParams().setParameter(CoreProtocolPNames.HTTP_CONTENT_CHARSET, "UTF-8");
//后端服务器的IP
String serverIP = "192.168.101.190";
//后端服务器的文件地址
StringBuilder backUrl = new StringBuilder();
backUrl.append(serverIP);
backUrl.append("/LBA/bigfile/");
backUrl.append(filename);
HttpGet httpGet = new HttpGet(backUrl.toString());
httpGet.getParams().setParameter(CoreProtocolPNames.HTTP_CONTENT_CHARSET, "UTF-8");
log.info("distribute bigfile to " + backUrl.toString());
HttpResponse backResponse;
try {
backResponse = httpClient.execute(httpGet);
// log.info(backResponse.getParams().getParameter(CoreProtocolPNames.HTTP_CONTENT_CHARSET));
HttpEntity httpEntity = backResponse.getEntity();
InputStream in = httpEntity.getContent();
// BufferedReader br = new BufferedReader(new InputStreamReader(httpEntity.getContent(), "UTF-8"));
byte[] buf = new byte[4096];
int readLength;
response.setCharacterEncoding("UTF-8");
ServletOutputStream out = response.getOutputStream();
while((readLength = in.read(buf)) != -1){
out.write(buf, 0, readLength);
}
in.close();
out.flush();
out.close();
} catch (ClientProtocolException e) {
StringWriter sw = new StringWriter();
e.printStackTrace(new PrintWriter(sw));
log.error("ClientProtocolException when redirect bigfile. " + sw.toString());
} catch (IOException e) {
StringWriter sw = new StringWriter();
e.printStackTrace(new PrintWriter(sw));
log.error("IOException when redirect bigfile. " + sw.toString());
}
long endTime = System.nanoTime();
System.out.println("Response time: " + (endTime-startTime) + " ns");
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
}
}
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以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
原文链接：http://blog.csdn.net/blue_jjw/article/details/8774150