《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：