ClientUI.java

//消息发送服务端

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

/**
 * 用户界面ClientUI
 */
public class ClientUI extends JFrame {
	JTextArea mainArea;

	JTextArea sendArea;

	ChatClient client;

	public void setClient(ChatClient client) {
		this.client = client;
	}

	public ClientUI(String IP) {
		super("教师端");
		Container contain = getContentPane();
		contain.setLayout(new BorderLayout());
		mainArea = new JTextArea();
		JScrollPane mainAreaP = new JScrollPane(mainArea);// 为文本区添加滚动条
		JPanel panel = new JPanel();
		panel.setLayout(new BorderLayout());
		sendArea = new JTextArea(3, 8);
		JButton sendBtn = new JButton("发送");
		sendBtn.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent ae) {
				client.sendMsg(sendArea.getText());
				mainArea.append("【教师端】" + sendArea.getText() + "\n");
				sendArea.setText("");
			}
		});
		/*JPanel ipPanel = new JPanel();
		ipPanel.setLayout(new FlowLayout(FlowLayout.LEFT, 10, 10));
		ipPanel.add(new JLabel("服务器："));
		ipArea = new JTextField(12);
		ipArea.setText("");
		ipPanel.add(ipArea);
		btnLink = new JButton("连接");
		ipPanel.add(btnLink);*/
		client = new ChatClient(IP, 6666, ClientUI.this);// 创建socket对象
		ClientUI.this.setClient(client);
		panel.add(sendBtn, BorderLayout.EAST);
		panel.add(sendArea, BorderLayout.CENTER);
		//contain.add(ipPanel, BorderLayout.NORTH);
		contain.add(mainAreaP, BorderLayout.CENTER);
		contain.add(panel, BorderLayout.SOUTH);
		setSize(500, 300);
		setVisible(true);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	}

}

/**
 * 通讯类ChatClient负责守候数据到来
 */
class ChatClient extends Thread {
	Socket sc;// 对象sc，用来处理与服务

	BufferedReader in;// 声明输入流缓冲区，用于存储服务器发来的信息

	PrintWriter out;// 声明打印输出流，用于信息的发送

	ClientUI ui;

	public ChatClient(String ip, int port, ClientUI ui) {// 初始化ChatClient类
		this.ui = ui;
		try {
			sc = new Socket(ip, port); // 创建sc, 用服务器ip和端口作参数
			System.out.println("已顺利联接到学生端。");
			out = new PrintWriter(sc.getOutputStream(), true);
			in = new BufferedReader(new InputStreamReader(sc.getInputStream()));
		} catch (Exception e) {
			System.out.println(e);
		}
		start();
	}

	public void run() { // 用于监听服务器端发送来的信息
		String msg = "";
		while (true) {
			try {
				msg = in.readLine();// 从缓冲区读入一行字符存于msg
			} catch (SocketException ex) {
				System.out.println(ex);
				break;
			} catch (Exception ex) {
				System.out.println(ex);
			}
			if (msg != null && msg.trim() != "") {// 若msg信息不为空
				System.out.println(">>" + msg);
				ui.mainArea.append(msg + "\n");// 把msg信息添加到客户端的文本区域内
			}
		}
	}

	public void sendMsg(String msg) {// 用于发送信息
		try {
			out.println("【教师端】" + msg);
		} catch (Exception e) {
			System.out.println(e);
		}
	}
}