《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：