Java网络编程，通过TCP,Socket实现多对一的局域网聊天室

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.net.Socket;
import java.util.List;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
/*这个类是服务器端的UI*/
public class ServerUI extends JFrame {
public static void main(String[] args) {
ServerUI serverUI = new ServerUI();
}

public JButton btStart;//启动服务器
public JButton btSend;//发送信息按钮
public JTextField tfSend;//需要发送的文本信息
public JTextArea taShow;//信息展示
public Server server;//用来监听客户端连接
static List<Socket> clients;//保存连接到服务器的客户端

public ServerUI() {
super("服务器端");
btStart = new JButton("启动服务");
btSend = new JButton("发送信息");
tfSend = new JTextField(10);
taShow = new JTextArea();

btStart.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
server = new Server(ServerUI.this);
}
});
btSend.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
server.sendMsg(tfSend.getText());
tfSend.setText("");
}
});
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
int a = JOptionPane.showConfirmDialog(null, "确定关闭吗？", "温馨提示",
JOptionPane.YES_NO_OPTION);
if (a == 1) {
server.closeServer();
System.exit(0); // 关闭
}
}
});
JPanel top = new JPanel(new FlowLayout());
top.add(tfSend);
top.add(btSend);
top.add(btStart);
this.add(top, BorderLayout.SOUTH);
final JScrollPane sp = new JScrollPane();
sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
sp.setViewportView(this.taShow);
this.taShow.setEditable(false);
this.add(sp, BorderLayout.CENTER);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(400, 300);
this.setLocation(100, 200);
this.setVisible(true);
}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
/*这个类是服务器端的等待客户端连接*/
public class Server extends Thread {
ServerUI ui;
ServerSocket ss;
BufferedReader reader;
PrintWriter writer;

public Server(ServerUI ui) {
this.ui = ui;
this.start();
}

public void run() {
try {

ss = new ServerSocket(1228);
ui.clients=new ArrayList<Socket>();
println("启动服务器成功：端口1228");

while (true) {
println("等待客户端");
Socket client = ss.accept();
ui.clients.add(client);
println("连接成功" + client.toString());
new ListenerClient(ui, client);
}
} catch (IOException e) {
println("启动服务器失败：端口1228");
println(e.toString());
e.printStackTrace();
}

}

public synchronized void sendMsg(String msg) {
try {
for (int i = 0; i < ui.clients.size(); i++) {
Socket client = ui.clients.get(i);
writer = new PrintWriter(client.getOutputStream(), true);
writer.println(msg);
}

} catch (Exception e) {
println(e.toString());
}
}

public void println(String s) {
if (s != null) {
this.ui.taShow.setText(this.ui.taShow.getText() + s + "\n");
System.out.println(s + "\n");
}
}

public void closeServer() {
try {
if (ss != null)
ss.close();
if (reader != null)
reader.close();
if (writer != null)
writer.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}

}
}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
/*这个类是服务器端的等待客户端发送信息*/
public class ListenerClient extends Thread {
BufferedReader reader;
PrintWriter writer;
ServerUI ui;
Socket client;
public ListenerClient(ServerUI ui, Socket client) {
this.ui = ui;
this.client=client;
this.start();
}
//为每一个客户端创建线程等待接收信息，然后把信息广播出去
public void run() {
String msg = "";
while (true) {
try {
reader = new BufferedReader(new InputStreamReader(
client.getInputStream()));
writer = new PrintWriter(client.getOutputStream(), true);
msg = reader.readLine();
sendMsg(msg);

} catch (IOException e) {
println(e.toString());
// e.printStackTrace();
break;
}
if (msg != null && msg.trim() != "") {
println(">>" + msg);
}
}
}
//把信息广播到所有用户
public synchronized void sendMsg(String msg) {
try {
for (int i = 0; i < ui.clients.size(); i++) {
Socket client = ui.clients.get(i);
writer = new PrintWriter(client.getOutputStream(), true);
writer.println(msg);
}

} catch (Exception e) {
println(e.toString());
}
}

public void println(String s) {
if (s != null) {
this.ui.taShow.setText(this.ui.taShow.getText() + s + "\n");
System.out.println(s + "\n");
}
}
}

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

public class ClientUI extends JFrame {
public static void main(String[] args) {
ClientUI client = new ClientUI();
}
public ClientUI() {
super("客户端");
btStart = new JButton("启动连接");
btSend = new JButton("发送信息");
tfSend = new JTextField(10);
tfIP = new JTextField(10);
tfPost = new JTextField(5);
taShow = new JTextArea();

btStart.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
server = new ClientThread(ClientUI.this);
}
});
btSend.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
server.sendMsg(tfSend.getText());
tfSend.setText("");
}
});
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
int a = JOptionPane.showConfirmDialog(null, "确定关闭吗？", "温馨提示",
JOptionPane.YES_NO_OPTION);
if (a == 1) {
System.exit(0); // 关闭
}
}
});
JPanel top = new JPanel(new FlowLayout());
top.add(tfSend);
top.add(btSend);
top.add(btStart);
this.add(top, BorderLayout.SOUTH);
final JScrollPane sp = new JScrollPane();
sp.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
sp.setViewportView(this.taShow);
this.taShow.setEditable(false);
this.add(sp, BorderLayout.CENTER);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.setSize(400, 300);
this.setLocation(600, 200);
this.setVisible(true);
}

public     JButton btStart;
public     JButton btSend;
public     JTextField tfSend;
public     JTextField tfIP;
public     JTextField tfPost;

public     JTextArea taShow;
public     ClientThread server;

}

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;

public class ClientThread extends Thread {
ClientUI ui;
Socket client;
BufferedReader reader;
PrintWriter writer;

public ClientThread(ClientUI ui) {
this.ui = ui;
try {
client = new Socket("127.0.0.1", 1228);//这里设置连接服务器端的IP的端口
println("连接服务器成功：端口1228");
reader = new BufferedReader(new InputStreamReader(
client.getInputStream()));
writer = new PrintWriter(client.getOutputStream(), true);
// 如果为 true，则 println、printf 或 format 方法将刷新输出缓冲区
} catch (IOException e) {
println("连接服务器失败：端口1228");
println(e.toString());
e.printStackTrace();
}
this.start();
}

public void run() {
String msg = "";
while (true) {
try {
msg = reader.readLine();
} catch (IOException e) {
println("服务器断开连接");

break;
}
if (msg != null && msg.trim() != "") {
println(">>" + msg);
}
}
}

public void sendMsg(String msg) {
try {
writer.println(msg);
} catch (Exception e) {
println(e.toString());
}
}

public void println(String s) {
if (s != null) {
this.ui.taShow.setText(this.ui.taShow.getText() + s + "\n");
System.out.println(s + "\n");
}
}

}