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()+"\n\r"+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()+"\n\r"+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