简易聊天客户端程序

import java.io.*;
import javax.swing.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;

public class simpleChatClientA {
    JTextArea incoming;
    BufferedReader reader;
    Socket sock;
    JTextField outgoing;
    PrintWriter writer;
    //build the interface
    public void go(){
        JFrame frame = new JFrame("Gaby's specific chatClient");
        JPanel mainPanel = new JPanel();
        /*此处为一大堆GUI组件 incoming 和 JScrollPane的设置
         * 我在此忽略 
         */
        outgoing = new JTextField(20);
        JButton sendButton = new JButton("send");
        
        mainPanel.add(outgoing);
        mainPanel.add(sendButton);
        sendButton.addActionListener(new buttonListener());
        
        frame.getContentPane().add(BorderLayout.CENTER, mainPanel);
        setUpNetWorking();
        Thread t = new Thread(new incomingReader());
        t.start();
        frame.setSize(300, 400);
        frame.setVisible(true);
    }
    
    //build the link between the class and the server
    public void setUpNetWorking(){
        try{
            sock = new Socket("192.168.0.105",5000);
            InputStreamReader streamReader = new InputStreamReader(sock.getInputStream());
            reader = new BufferedReader(streamReader);
            writer = new PrintWriter(sock.getOutputStream());
            System.out.println("networking established");
        }catch(Exception ex){
            ex.printStackTrace();
        }
    }
    
    //register to a button and send message to server
    class buttonListener implements ActionListener{
        public void actionPerformed(ActionEvent ev){
            writer.println(outgoing.getText());//因为输出时，只有等到缓冲区满了才输出，有些时候输出的内容比较少的时候，没有充满缓冲区，不会立刻输出的。
            writer.flush();
        }
    }
    //Runnable类使用多线程
    public class incomingReader implements Runnable{
        String message;
        public void run(){
            try{
                while((message = reader.readLine()) != null ){
                    System.out.println("read " + message);
                    incoming.append(message + "
");
                }
            }catch(Exception ex){
                ex.printStackTrace();
            }
        }
    }
    
    //main
    public static void main(String args[]){
        simpleChatClientA client = new simpleChatClientA();
        client.go();
    }
}

该程序可分为以下功能块：

• go
• setUpNetWorking
• buttonListener implements ActionListener
• incomingReader implements Runnable

go：

用于建立GUI，并调用 setUpNetWorking()，并且启动用于接收服务器信息的新线

setUpNetWorking:

通过让Socket sock充当这个对象的实例变量，使得其生存期伴随整个程序

同时，设置好reader和writer

buttonListener implements ActionListener(内部类)：

在go里面向button注册了监听，如果遇到click，则由buttonListener对象处理，处理方式则是向服务器发送信息，意味着writer得是实例变量

incomingReader implements Runnable(内部类)：

里面的run函数是新线程执行的内容，也因此用到了外部类对象的reader