《安卓网络编程》之第二篇 java环境下网络通信的综合应用

　　经过前面内容的学习，我们了解了Java技术中实现网络通信的基本知识。下面将通过一个具体视力的实现过程，讲解客户端和服务器端通信的流程。

服务器端的实现文件是 Server.java,代码如下：

 import java.io.*;

 import java.awt.*;

 import java.awt.event.*;

 import javax.swing.*;

 import java.net.*;

 import java.util.*;

 class Conn extends Thread{

     private JTextArea txt;

     private Socket st;

     private String msg = null;

     private BufferedReader br = null;

     private PrintStream ps;

     public Conn(Socket st,JTextArea txt){

         this.st = st;

         this.txt = txt;

         start();

     }

     public void run(){

         try{

             br = new BufferedReader(new InputStreamReader(st.getInputStream()));

             ps = new PrintStream(new DataOutputStream(st.getOutputStream()));

         }catch(Exception e){

             System.err.println("input failed");

         }

         while(true){

             try{

                 msg = br.readLine();

                 txt.append("从客户端收到信息:"+msg+'\n');

                 txt.append("信息接受时间是:"+new Date()+"\n");

                 Server.send(msg);

             }catch(Exception e){

                 System.err.println("connection closed");

                 break;

             }

         }

     }

     public void send(String msg){

       ps.println(msg);

     }

 }

 public class Server extends JFrame{

     private JTextArea txt;

     private ServerSocket ss;

     private static java.util.List<Conn> conns = new ArrayList<Conn>();

     public Server(){

        txt = new JTextArea();

        this.setTitle("服务器");

        this.setLayout(new BorderLayout());

        this.add(new JScrollPane(txt),BorderLayout.CENTER);

        this.setSize(500,300);

        this.setVisible(true);

        run();

     }

     public void run(){

         try{

             ss = new ServerSocket(8000);

         }catch(Exception e){

             System.err.println("open socket failed");

         }

         txt.append("服务器已经启动！"+"\n");

         while(true){

             try{

                 Socket st=ss.accept();

                 conns.add(new Conn(st,txt));

             }

             catch(IOException ex){

                 System.err.println(ex);

             }

         }

     }

     public static void send(String msg){

       for(Conn c:conns)

         c.send(msg);

     }

     public static void main(String args[]){

         Server myserver=new Server();

     }

 }

客户端的实现文件是Client.java,代码如下：

 import java.io.*;

 import java.awt.*;

 import java.awt.event.*;

 import javax.swing.*;

 import java.net.*;

 import java.util.*;

 public class Client extends JFrame implements ActionListener{

     final JTextArea txta;

     JTextField txtf;

     JPanel pl;

     JButton bt;

     BufferedReader br;

     DataOutputStream out;

     PrintStream ps;

     Container f = this.getContentPane();

         public Client() {

             f.setLayout(new BorderLayout());

             txta = new JTextArea();

             f.add(txta,BorderLayout.CENTER);

             txtf = new JTextField(20);

             bt = new JButton ("发送");

             pl = new JPanel();

             pl.setLayout(new FlowLayout());

             pl.add(txtf);

             pl.add(bt);

             bt.addActionListener(this);

             f.add(pl,BorderLayout.SOUTH);//The south layout constraint (bottom of container).

             setTitle("信息发送端");

             setSize(500,300);

             setVisible(true);

             run();

             Thread t = new Thread(new Runnable() {

                 public void run() {

                     while(true) {

                         try{

                             txta.append("收到消息："+br.readLine()+"\n");

                         }catch(Exception ex) {}

                     }

                 }

             });

             t.start();

         }

     public void actionPerformed(ActionEvent e) {

         // TODO Auto-generated method stub

         if(e.getSource() == bt) {

             String msg = txtf.getText();

             try{

                 ps.println(msg);

                 txta.append("已经发送消息："+msg+"\n");

             }catch(Exception ex){

                 txta.append(ex.toString()+"\n");

             }

         }

     }

     private void run() {

         try

         {

             Socket sc= new Socket("127.0.0.1",8000);

             out = new DataOutputStream(sc.getOutputStream());

             ps = new PrintStream(out);

             br = new BufferedReader(new InputStreamReader(sc.getInputStream()));

         }

         catch(IOException ex)

         {

             txta.append(ex.toString()+"\n");

         }

     }

     public static void main(String[] args) {

         Client myclient = new Client();

     }

 }

同样是先执行服务器端，在执行客户端，效果如下：