<h3>最近復(fù)習(xí)計(jì)算機(jī)網(wǎng)絡(luò)，復(fù)習(xí)完應(yīng)用層之后對(duì)于理論知識(shí)還是沒(méi)有一個(gè)深刻的概念，索性就動(dòng)手用Java Socket API 模擬做一個(gè)HTTP服務(wù)器，鞏固一下應(yīng)用層的知識(shí)。</h3>
<blockquote>
HTTP基于TCP協(xié)議，協(xié)議采用了請(qǐng)求/響應(yīng)模型?？蛻?hù)端向服務(wù)器發(fā)送一個(gè)請(qǐng)求，請(qǐng)求頭包含請(qǐng)求的方法、URL、協(xié)議版本、以及包含請(qǐng)求修飾符、客戶(hù)信息和內(nèi)容的類(lèi)似于MIME的消息結(jié)構(gòu)。服務(wù)器以一個(gè)狀態(tài)行作為響應(yīng)，響應(yīng)的內(nèi)容包括消息協(xié)議的版本，成功或者錯(cuò)誤編碼加上包含服務(wù)器信息、實(shí)體元信息以及可能的實(shí)體內(nèi)容——百度百科。

話(huà)不多說(shuō)，還是直接上圖。
</blockquote>

http.png

具體字段這里不作解釋?zhuān)欢恼?qǐng)先自己了解http協(xié)議。這里主要是根據(jù)請(qǐng)求響應(yīng)這一過(guò)程模擬HTTP服務(wù)器。
下面是代碼：
<pre>

package com.example.httpserver;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class HttpServer {
    private static final Integer port = 80;//HTTP默認(rèn)端口80
    
    public static void main(String[] args) {
        ServerSocket serverSocket;
        
        try {
            //建立服務(wù)器Socket,監(jiān)聽(tīng)客戶(hù)端請(qǐng)求
            serverSocket = new ServerSocket(port);
            System.out.println("Server is running on port:"+serverSocket.getLocalPort());
            //死循環(huán)不間斷監(jiān)聽(tīng)客戶(hù)端請(qǐng)求
            while(true){
                final Socket socket = serverSocket.accept();
                System.out.println("biuld a new tcp link with client,the cient address:"+  
                        socket.getInetAddress()+":"+socket.getPort());
                //并發(fā)處理HTTP客戶(hù)端請(qǐng)求
                service(socket);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    
    public static void service(Socket socket)
    {
        new Thread(){
            public void run(){
                InputStream inSocket;
                try {
                    //獲取HTTP請(qǐng)求頭
                    inSocket = socket.getInputStream();
                    int size = inSocket.available();
                    byte[] buffer = new byte[size];
                    inSocket.read(buffer);
                    String request = new String(buffer);
                    System.out.println("ClientBrowser:\n"+request+"\n"
                            + "------------------------------------------------------------------");
                    
                    String firstLineOfRequest = "";
                    String[] heads;
                    String uri = "/index.html";
                    String contentType ="";
                    if(request.length() > 0){
                        firstLineOfRequest = request.substring(0,request.indexOf("\r\n"));
                        heads = firstLineOfRequest.split(" ");
                        uri = heads[1];
                        
                        if(uri.indexOf("html") != -1){
                            contentType = "text/html";
                        }else{
                            contentType = "application/octet-stream";
                        }
                    }
                    //將響應(yīng)頭發(fā)送給客戶(hù)端
                    String responseFirstLine = "HTTP/1.1 200 OK\r\n";
                    
                    String responseHead = "Content-Type:" + contentType +"\r\n";
                    
                    OutputStream outSocket = socket.getOutputStream();
                    System.out.println("ServerResponse:\n"+responseFirstLine+"\n"+responseHead+"\n"
                            + "--------------------------------------------------------------------");
                    outSocket.write(responseFirstLine.getBytes());
                    outSocket.write(responseHead.getBytes());
                    //通過(guò)HTTP請(qǐng)求中的uri讀取相應(yīng)文件發(fā)送給客戶(hù)端
                    FileInputStream writehtml = new FileInputStream(new File("wwwroot"+uri));
                    outSocket.write("\r\n".getBytes());  
                    byte[] htmlbuffer = new byte[writehtml.available()];
                    if(writehtml !=null){
                        int len = 0;
                        System.out.println("writeHtml");
                        while((len = writehtml.read(htmlbuffer)) != -1){
                            outSocket.write(htmlbuffer, 0,len);
                        }
                    }
                    outSocket.close();
                    socket.close();
                
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }.start();
    }

}

</pre>

代碼看注釋也很容易理解?，F(xiàn)在我們?cè)跒g覽器中輸入服務(wù)器地址+要訪(fǎng)問(wèn)的文件

request.png

在看我們控制臺(tái)輸出的內(nèi)容：

response.png

<h5>以上就是Java Socket 簡(jiǎn)單的模擬HTTP服務(wù)器全過(guò)程。</h5>