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java實(shí)現(xiàn)socket客戶端連接服務(wù)端

更新時(shí)間：2015年10月08日 11:09:33 投稿：hebedich

本文是個(gè)人剛剛開始學(xué)習(xí)如何通過(guò)socket去發(fā)送信息下邊的案例，也是書上的在這留下筆記，最后附上一個(gè)實(shí)例，有需要的小伙伴可以參考下。

本例只做簡(jiǎn)單功能演示，代碼并不嚴(yán)謹(jǐn)，只是說(shuō)明客戶端如何實(shí)現(xiàn)連接服務(wù)端簡(jiǎn)單代碼。

代碼在集成Eclipse工具下測(cè)試編譯運(yùn)行環(huán)境如下圖所示：

客戶端echoClient.java代碼：

package com.zhengzz.echo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;

class EchoC{
  
  private Socket socket;
  
  public EchoC() {
    // TODO Auto-generated constructor stub
    try {
      socket = new Socket("localhost", 60000);
    } catch (UnknownHostException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
  
  public void Client() {
    try {
      BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
      PrintWriter pw = new PrintWriter(socket.getOutputStream(), true);
      BufferedReader lbr = new BufferedReader(new InputStreamReader(System.in));
      
      String linestr = null;
      while ((linestr = lbr.readLine()) != null) {
        
        pw.println(linestr);
        
        System.out.println(br.readLine());
        
        if (linestr.equals("bye#")) {
          break;
        }
      }
      
      
    } catch (IOException e) {
      e.printStackTrace();
    }
  }
}

public class echoClient {

  public static void main(String[] args) {
    new EchoC().Client();
  }

}

服務(wù)端echoServer.java代碼：

package com.zhengzz.echo;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

class EchoS{
  
  private ServerSocket serverSocket;
  
  public EchoS() {
    
    try {
      serverSocket = new ServerSocket(60000);
    } catch (IOException e) {
      e.printStackTrace();
    }
    
  }
  
  public void Server() {
    while (true) {
      try {
        Socket socket = serverSocket.accept();
        
        System.out.println("client:" + socket.getInetAddress() + ":" + socket.getLocalPort());

        BufferedReader br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter pw = new PrintWriter(socket.getOutputStream(), true);

        String linestr;

        while ((linestr = br.readLine()) != null) {

          System.out.println(linestr);

          pw.println("--->" + linestr);

        }
      } catch (IOException e) {
        System.out.println("連接斷開：（");
      }

    }
}
}

public class echoServer {

  public static void main(String[] args) {
    new EchoS().Server();
  }

}

我在Eclipse工具下直接調(diào)試結(jié)果如下：

下面我們?cè)賮?lái)看一個(gè) HelloWord 級(jí)別的 Java Socket 通信的例子。通訊過(guò)程：

先啟動(dòng) Server 端，進(jìn)入一個(gè)死循環(huán)以便一直監(jiān)聽(tīng)某端口是否有連接請(qǐng)求。然后運(yùn)行 Client 端，客戶端發(fā)出連接請(qǐng)求，服務(wù)端監(jiān)聽(tīng)到這次請(qǐng)求后向客戶端發(fā)回接受消息，連接建立，啟動(dòng)一個(gè)線程去處理這次請(qǐng)求，然后繼續(xù)死循環(huán)監(jiān)聽(tīng)其他請(qǐng)求。客戶端輸入字符串后按回車鍵，向服務(wù)器發(fā)送數(shù)據(jù)。服務(wù)器讀取數(shù)據(jù)后回復(fù)客戶端數(shù)據(jù)。這次請(qǐng)求處理完畢，啟動(dòng)的線程消亡。如果客戶端接收到 "OK" 之外的返回?cái)?shù)據(jù)，會(huì)再次發(fā)送連接請(qǐng)求并發(fā)送數(shù)據(jù)，服務(wù)器會(huì)為這次連接再次啟動(dòng)一個(gè)線程來(lái)進(jìn)行響應(yīng)。。。直到當(dāng)客戶端接收到的返回?cái)?shù)據(jù)為 "OK" 時(shí)，客戶端退出。

服務(wù)端源代碼：

package com.defonds.socket.begin; 
 
import java.io.BufferedReader; 
import java.io.DataInputStream; 
import java.io.DataOutputStream; 
import java.io.InputStreamReader; 
import java.net.ServerSocket; 
import java.net.Socket; 
 
public class Server { 
  public static final int PORT = 12345;//監(jiān)聽(tīng)的端口號(hào)   
   
  public static void main(String[] args) {  
    System.out.println("服務(wù)器啟動(dòng)...\n");  
    Server server = new Server();  
    server.init();  
  }  
  
  public void init() {  
    try {  
      ServerSocket serverSocket = new ServerSocket(PORT);  
      while (true) {  
        // 一旦有堵塞, 則表示服務(wù)器與客戶端獲得了連接  
        Socket client = serverSocket.accept();  
        // 處理這次連接  
        new HandlerThread(client);  
      }  
    } catch (Exception e) {  
      System.out.println("服務(wù)器異常: " + e.getMessage());  
    }  
  }  
  
  private class HandlerThread implements Runnable {  
    private Socket socket;  
    public HandlerThread(Socket client) {  
      socket = client;  
      new Thread(this).start();  
    }  
  
    public void run() {  
      try {  
        // 讀取客戶端數(shù)據(jù)  
        DataInputStream input = new DataInputStream(socket.getInputStream()); 
        String clientInputStr = input.readUTF();//這里要注意和客戶端輸出流的寫方法對(duì)應(yīng),否則會(huì)拋 EOFException 
        // 處理客戶端數(shù)據(jù)  
        System.out.println("客戶端發(fā)過(guò)來(lái)的內(nèi)容:" + clientInputStr);  
  
        // 向客戶端回復(fù)信息  
        DataOutputStream out = new DataOutputStream(socket.getOutputStream());  
        System.out.print("請(qǐng)輸入:\t");  
        // 發(fā)送鍵盤輸入的一行  
        String s = new BufferedReader(new InputStreamReader(System.in)).readLine();  
        out.writeUTF(s);  
         
        out.close();  
        input.close();  
      } catch (Exception e) {  
        System.out.println("服務(wù)器 run 異常: " + e.getMessage());  
      } finally {  
        if (socket != null) {  
          try {  
            socket.close();  
          } catch (Exception e) {  
            socket = null;  
            System.out.println("服務(wù)端 finally 異常:" + e.getMessage());  
          }  
        }  
      }  
    }  
  }  
}

客戶端源代碼：

package com.defonds.socket.begin; 
 
import java.io.BufferedReader; 
import java.io.DataInputStream; 
import java.io.DataOutputStream; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.Socket; 
 
public class Client { 
  public static final String IP_ADDR = "localhost";//服務(wù)器地址  
  public static final int PORT = 12345;//服務(wù)器端口號(hào)  
   
  public static void main(String[] args) {  
    System.out.println("客戶端啟動(dòng)...");  
    System.out.println("當(dāng)接收到服務(wù)器端字符為 \"OK\" 的時(shí)候, 客戶端將終止\n");  
    while (true) {  
      Socket socket = null; 
      try { 
        //創(chuàng)建一個(gè)流套接字并將其連接到指定主機(jī)上的指定端口號(hào) 
        socket = new Socket(IP_ADDR, PORT);  
          
        //讀取服務(wù)器端數(shù)據(jù)  
        DataInputStream input = new DataInputStream(socket.getInputStream());  
        //向服務(wù)器端發(fā)送數(shù)據(jù)  
        DataOutputStream out = new DataOutputStream(socket.getOutputStream());  
        System.out.print("請(qǐng)輸入: \t");  
        String str = new BufferedReader(new InputStreamReader(System.in)).readLine();  
        out.writeUTF(str);  
          
        String ret = input.readUTF();   
        System.out.println("服務(wù)器端返回過(guò)來(lái)的是: " + ret);  
        // 如接收到 "OK" 則斷開連接  
        if ("OK".equals(ret)) {  
          System.out.println("客戶端將關(guān)閉連接");  
          Thread.sleep(500);  
          break;  
        }  
         
        out.close(); 
        input.close(); 
      } catch (Exception e) { 
        System.out.println("客戶端異常:" + e.getMessage());  
      } finally { 
        if (socket != null) { 
          try { 
            socket.close(); 
          } catch (IOException e) { 
            socket = null;  
            System.out.println("客戶端 finally 異常:" + e.getMessage());  
          } 
        } 
      } 
    }  
  }  
}

注意： Socket 輸出流寫數(shù)據(jù)方法是 writeUTF 時(shí)，輸入流讀取相關(guān)數(shù)據(jù)要用 readUTF。否則會(huì)拋 EOFException 異常。

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