Java Socket 实现HTTP服务器核心

原文链接：http://www.ihuxu.com/p/235.html

 

首先了解下HTTP协议：

wikiPedia的说明很好，在此不重复了。链接：http://zh.wikipedia.org/wiki/Http

源码分析：

概述：此两个代码段，完成服务器监听，线程处理短请求服务和应答（符合伪HTTP协议，“伪”即判断协议格式不严谨）。展示了利用java socket完成http通信的核心原理代码，希望给初次学习socket或者第一次利用java来实现HTTP协议服务器的朋友提供些帮助。

利用 Java Socket 网络编程来绑定服务器某个端口进行监听。

 1 package JHServer;
 2
 3 import java.io.IOException;
 4 import java.net.ServerSocket;
 5 import java.net.Socket;
 6
 7 public class Server {
 8
 9     private static int PORT = 1720;
10     public static String charset = "utf-8";
11     private ServerSocket ss;
12     private Socket client;
13
14     public static void main(String[] args) {
15         new Server();
16     }
17
18     public Server() {
19         try {
20             this.ss = new ServerSocket(this.PORT);
21 System.out.println("Server Listening Port " + this.PORT + "...");
22             boolean isGo = true;
23             while(isGo){
24                 this.client = this.ss.accept();
25 System.out.println("One Client Connected. " + this.client);
26                 ClientThread ct = new ClientThread(this.client);
27                 Thread t = new Thread(ct);
28                 t.start();
29 System.out.println("One Client Thread Already Started...");
30             }
31         } catch (IOException e) {
32             e.printStackTrace();
33         } finally {
34             try{
35                 if(this.ss != null){
36                     this.ss.close();
37                     this.ss = null;
38                 }
39                 if(this.client != null){
40                     this.client.close();
41                     this.client = null;
42                 }
43             } catch(IOException e) {
44                 e.printStackTrace();
45             }
46         }
47     }
48
49 }  

说明：上述代码完成了服务端口（1720，你懂么）的监听，并同时利用线程了处理每个客户端（Client ）的消息请求，以减少服务器处理”短请求“阻塞问题。

下述代码完成请求是否符合伪HTTP协议，并完成响应消息。

  1 package JHServer;
  2
  3 import java.io.*;
  4 import java.net.Socket;
  5 import java.util.Date;
  6
  7 import action.ManagerEachMatchInfo;
  8
  9 import view.*;
 10
 11 public class ClientThread implements Runnable {
 12
 13     private float requestDelay = (float)0.5;//
 14
 15     private Socket _s;
 16     private BufferedReader i;
 17     private PrintStream o;
 18
 19     public ClientThread(Socket s) {
 20         this._s = s;
 21     }
 22
 23     public void run() {
 24         try {
 25             this.i = new BufferedReader(new InputStreamReader(this._s.getInputStream()));
 26             this.o = new PrintStream(this._s.getOutputStream());
 27
 28             String request = this.getValidRequest();
 29
 30             if( !request.equals("") ) {
 31                 System.out.print("当前虚拟机最大可用内存为:");
 32                 System.out.println(Runtime.getRuntime().maxMemory()/1024/1024+"M");
 33                 System.out.print("当前，虚拟机已占用内存:");
 34                 System.out.println(Runtime.getRuntime().totalMemory()/1024/1024+"M");
 35                 this.o.println("HTTP/1.1 200 OK");
 36                 Date now = new Date();
 37                 this.o.println("Data:" + now);
 38                 this.o.println("Server: JHServer");
 39                 this.o.println("Access-Control-Allow-Origin:*");
 40
 41                 this.o.println("Content-Type: text/html; charset=UTF-8");
 42                 this.o.println();
 43                 String content = null;
 44                 IndeMatchInfo imi = new IndeMatchInfo(22,22,2,2,22,(double)0.0,"S7-200");
 45                 content = imi.getHTML();
 46
 47                 imi.clear();
 48                 imi = null;
 49                 System.out.print("当前虚拟机最大可用内存为:");
 50                 System.out.println(Runtime.getRuntime().maxMemory()/1024/1024+"M");
 51                 System.out.print("当前，虚拟机已占用内存:");
 52                 System.out.println(Runtime.getRuntime().totalMemory()/1024/1024+"M");
 53
 54                 this.o.println(content);
 55                 content = "";
 56                 this.o.flush();
 57
 58             }
 59
 60         } catch (IOException e) {
 61             e.printStackTrace();
 62         } finally {
 63             this.close();
 64         }
 65
 66     }
 67
 68     private String getValidRequest() {
 69
 70         float second = (float) 0.0;
 71         boolean isGo = true;
 72         String request = null;
 73         try {
 74             while (!this.i.ready()) {
 75                 second += 0.01;
 76                 if (second > this.requestDelay) {
 77                     System.out.println("One Client Delayed " + this._s);
 78                     isGo = false;
 79                     break;
 80                 }
 81                 Thread.sleep(10);
 82             }
 83
 84             if (isGo == true) {
 85                 request = this.i.readLine();
 86                 if( request.contains("GET /") && request.contains(" HTTP/") ) {
 87                     request = request.substring(request.indexOf("/"),request.indexOf(" HTTP/"));
 88 System.out.println("Client Request Info: " + request);
 89                 } else {
 90                     isGo = false;
 91                 }
 92             }
 93         } catch (InterruptedException e) {
 94             e.printStackTrace();
 95         } catch (IOException e) {
 96             e.printStackTrace();
 97         } finally {
 98             if(isGo == true) {
 99                 return request;
100             } else {
101                 return "null";
102             }
103         }
104     }
105
106     private void close() {
107         try {
108             if (this.i != null) {
109                 this.i.close();
110                 this.i = null;
111             }
112             if (this.o != null) {
113                 this.o.close();
114                 this.o = null;
115             }
116             if (this._s != null) {
117                 this._s.close();
118                 this._s = null;
119             }
120 System.out.println("One Client Disconnected...");
121         } catch (IOException e) {
122             e.printStackTrace();
123         }
124     }
125
126 }  

说明：

1、getValidRequest() 验证请求消息是否满足伪HTTP协议。比如：GET /images/logo.gif HTTP/1.1，则会返回"/images/logo.gif"。若不符合伪HTTP协议或者请求时不发送任何消息头（比如通过telnet访问，此情况最大延迟0.5秒），则会返回空串。

2、close()，释放内存，同时线程结束。

3、run()，短请求的线程主体，在此处可以进行数据逻辑处理，并返回特定消息内容。