Java-在线聊天系统-线程

一、概述

1.目标：在上一个版本非线程的聊天系统中，出于要不断监听接收新client和接收client发出的信息，把accept()和DataInputStream.readUTF()分别写在了while()死循环里，由于俩方法都是阻塞性方法，所以一方阻塞，另一方永远得不到执行，所以，在上述代码中，只能监听第一个client的发送信息，新的client永远连接不上。

2.思路：

(1)把socet.accept()接收线程和DataInputStream.readUTF()的处理分开，把前者交给server端的处理，server端把接收到的clent封装到线程里，把DataInputStream.readUTF()的逻辑交给线程处理。

(2)采用异步IO

二、代码

1.ChatServer.java

import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;


public class ChatServer{
	
	private ServerSocket ss = null;
	private boolean started = false;
	
	public static void main(String[] args) {
		new ChatServer().start();
	}

	
	public void start(){
		
		try {
			ss = new ServerSocket(8888);
			started = true;
		} catch (IOException e1) {
			e1.printStackTrace();
		}
		
		try {
			while(started){
				//!!!!!注意accept()是阻塞性方法，当被readUTF()阻塞时它不会被执行
				Socket s = ss.accept();
System.out.println("a client connect------"+s);
				new Thread(new Client(s)).start();
			}
		} catch (EOFException e) {
			System.out.println("客户端已关闭！");
		} catch (IOException e) {
			e.printStackTrace();
		}finally{
			try {
				//if(dis != null ) dis.close();
				//if(s != null ) s.close();
				if(ss != null ) ss.close();
			} catch (Exception e) {
				e.printStackTrace();
			}
		}
	}
	
	private class Client implements Runnable{
		
		private Socket s;
		private DataInputStream dis = null;
		boolean bConnect = false;
		
		public Client(Socket s) {
			super();
			this.s = s;
			try {
				dis = new DataInputStream(s.getInputStream());
				bConnect = true;
			} catch (IOException e) {
				e.printStackTrace();
			}
		}


		@Override
		public void run() {
				try {
					while(bConnect){
					//!!!!!注意readUTF()是阻塞性方法
					System.out.println(dis.readUTF());
					}
				} catch (EOFException e) {
		            System.out.println("客户端已关闭！");
		        } 
				catch (IOException e) {
					e.printStackTrace();
				}finally{
					try {
						if(dis != null ) dis.close();
						if(s != null ) s.close();
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
			}
		}
		

}

　　

2.ChatClient.java

import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Socket;
import java.net.UnknownHostException;


public class ChatClient extends Frame{

	private TextField tfText;
	private TextArea taContent;
//	private Button btnSend;
	private Socket socket;
	private DataOutputStream dos;
	
	public void launchFrame(){
		
		addWindowListener(new WindowAdapter() {
			 public void windowClosing(WindowEvent e) {
				 disconnect();
				 System.exit(0);
			 }
		});
		
		tfText = new TextField();
		taContent = new TextArea();
//		btnSend = new Button("发送");
//		
//		btnSend.addActionListener(new ActionListener() {
//			@Override
//			public void actionPerformed(ActionEvent e) {
//				//taContent.setText(taContent.getText()+"

"+tfText.getText());
//				//tfText.setText("");
//				try {
//					DataOutputStream dos = new DataOutputStream(socket.getOutputStream());
//					dos.writeUTF(tfText.getText());
//					dos.close();
//					socket.close();
//				} catch (IOException e1) {
//					e1.printStackTrace();
//				}
//			}
//		});
		
		tfText.addActionListener(new TFListener());
		
		add(taContent,BorderLayout.NORTH);
		add(tfText,BorderLayout.CENTER);
//		add(btnSend,BorderLayout.SOUTH);
		setLocation(300, 100);
		pack();
		setVisible(true);
		connect("localhost", 8888);
	}
	
	//当调用了此方法，会自动把成员变量给socket连接上server
	public void  connect(String address, int port){
		try {
			socket = new Socket(address, port);
			dos = new DataOutputStream(socket.getOutputStream());
		} catch (UnknownHostException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	//退出时释放资源
	public void disconnect(){
		try {
			if(dos != null ) dos.close();
			if(socket != null ) socket.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	class TFListener implements ActionListener{

		@Override
		public void actionPerformed(ActionEvent e) {
			taContent.setText(taContent.getText().trim()+"

"+tfText.getText());
			
			try {
				dos.writeUTF(tfText.getText());
				dos.flush();
				tfText.setText("");
				//dos.close();
				//socket.close();
			} catch (IOException e1) {
				e1.printStackTrace();
			}
		}
	}
	
	public static void main(String[] args) {
		new ChatClient().launchFrame();
	}
}

　　

三、运行结果