HTTP1.0工作原理

1.HTTP工作原理

《HTTP响应报文与工作原理详解》讲的比较详细了。

2.示例

（1）server端程序如下：

 package org.yeyouluo.demo.jsp;

 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.net.ServerSocket;
 import java.net.Socket;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;

 /**
  * 实现HTTP 1.0的服务器，对于所有的HTTP请求，会把HTTP请求头响应回去。
  * @author yeyouluo
  *
  */
 public class MyHTTPServer {

     public static void main(String[] args) throws IOException {
         int port = 80;
         ServerSocket serverSocket = new ServerSocket(port);
         System.out.println("启动服务，绑定端口： " + port);

         ExecutorService fixedThreadPool = Executors.newFixedThreadPool(30);  //5.线程池

         //6.这个循环不停监听socket连接，使用SocketHandler处理连入的socket，而这个处理是放在线程池中的。
         while(true){
             Socket clientSocket = serverSocket.accept();
             System.out.println("新的连接"+clientSocket.getInetAddress() + ":" + clientSocket.getPort());
             try{
                 fixedThreadPool.execute(new SocketHandler(clientSocket));
             }catch(Exception e){
                 e.printStackTrace();
             }
         }
     }

 }

 class SocketHandler implements Runnable{
     static final String CRLF = "\r\n";  //1.换行符
     private Socket clientSocket;

     public SocketHandler(Socket clientSocket) {
         super();
         this.clientSocket = clientSocket;
     }

     public void handleSocket(Socket clientSocket) throws IOException{
         BufferedReader in = new BufferedReader(
                             new InputStreamReader(clientSocket.getInputStream())
                             );

         PrintWriter out = new PrintWriter(
                             new BufferedWriter(new OutputStreamWriter(clientSocket.getOutputStream()))
                             ,true);

         String requestHeader = "";
         String s;
         while( (s = in.readLine()) != null ){
             s +=  CRLF;  //2.很重要，默认情况下in.readLine的结果中'\r\n'被去掉了
             requestHeader += s;
             if( CRLF.equals(s) ){  //如果读取的一行数据只有换行符，说明请求头已经结束了
                 break;
             }
         }

          System.out.println("客户端请求头：\n" + requestHeader);

          String responseBody = "客户端的请求头是：\n"+requestHeader;
          String responseHeader = "HTTP/1.0 200 OK\r\n" +
                     "Content-Type: text/plain; charset=UTF-8\r\n" +
                     "Content-Length: "+responseBody.getBytes().length+"\r\n" +
                     "\r\n";
          System.out.println("响应头：\n" + responseHeader);

          out.write(responseHeader);
          out.write(responseBody);
          out.flush();

          out.close();
          in.close();
          clientSocket.close();
     }

     @Override
     public void run() {
         try {
             handleSocket(clientSocket);
         } catch (IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

 }

server端

启动server端。

（2）client端直接通过浏览器或curl工具发送http请求即可。比如在浏览器中输入http://127.0.0.1  。

（3）server端控制台打印如下：

3.参考

http://wiki.jikexueyuan.com/project/java-web/00-02.html