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();
        }
    }
    
}

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