ClientForm代码：

package GUISocket.chat.Client;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.EventQueue;import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JTextField;
import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.ScrollPaneConstants;
import javax.swing.border.EmptyBorder;import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;public class ClientForm extends JFrame {private JPanel contentPane;DefaultListModel<String> itemUsers;private JTextField textIP;private JTextField textPort;public JTextField textUser;public JTextArea textLog;public JList listUser;public JTextArea textSend ;public static void main(String[] args) {EventQueue.invokeLater(new Runnable() {public void run() {try {ClientForm frame = new ClientForm();frame.setVisible(true);ClientMG.getClientMG().setClientForm(frame);} catch (Exception e) {e.printStackTrace();}}});}public ClientForm() {setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setBounds(100, 100, 589, 607);contentPane = new JPanel();contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));setContentPane(contentPane);contentPane.setLayout(null);JLabel label = new JLabel("配置信息");label.setBounds(10, 10, 54, 15);contentPane.add(label);JLabel lblIp = new JLabel("IP");lblIp.setBounds(10, 35, 27, 15);contentPane.add(lblIp);textIP = new JTextField();textIP.setText("192.168.1.2");textIP.setBounds(33, 35, 92, 21);contentPane.add(textIP);textIP.setColumns(10);JLabel label_1 = new JLabel("端口");label_1.setBounds(137, 35, 38, 15);contentPane.add(label_1);textPort = new JTextField();textPort.setText("8900");textPort.setBounds(168, 32, 66, 21);contentPane.add(textPort);textPort.setColumns(10);JLabel label_2 = new JLabel("用户名");label_2.setBounds(255, 38, 54, 15);contentPane.add(label_2);textUser = new JTextField();textUser.setBounds(302, 35, 66, 21);contentPane.add(textUser);textUser.setColumns(10);JButton LOGIN = new JButton("登录");LOGIN.setBounds(395, 34, 66, 23);contentPane.add(LOGIN);JButton btnClose = new JButton("关闭");btnClose.addActionListener(new BtnCloseActionListener());btnClose.setBounds(480, 31, 71, 23);contentPane.add(btnClose);JPanel panel = new JPanel();panel.setBounds(0, 10, 573, 61);contentPane.add(panel);panel.setLayout(null);JPanel panel_1 = new JPanel();panel_1.setBounds(0, 81, 573, 369);contentPane.add(panel_1);panel_1.setLayout(null);JLabel label_3 = new JLabel("聊天记录");label_3.setBounds(10, 10, 54, 15);panel_1.add(label_3);JScrollPane scrollPane = new JScrollPane();scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);scrollPane.setBounds(20, 35, 323, 324);panel_1.add(scrollPane);textLog = new JTextArea();textLog.setWrapStyleWord(true);textLog.setLineWrap(true);scrollPane.setViewportView(textLog);JLabel label_4 = new JLabel("在线用户");label_4.setBounds(351, 10, 54, 15);panel_1.add(label_4);JScrollPane scrollPane_1 = new JScrollPane();scrollPane_1.setBounds(353, 35, 210, 324);panel_1.add(scrollPane_1);this.itemUsers=new DefaultListModel<String>();this.listUser=new JList(itemUsers);scrollPane_1.setViewportView(this.listUser);JPanel panel_2 = new JPanel();panel_2.setBounds(10, 449, 553, 119);contentPane.add(panel_2);panel_2.setLayout(null);JLabel label_5 = new JLabel("操作");label_5.setBounds(10, 10, 54, 15);panel_2.add(label_5);JScrollPane scrollPane_2 = new JScrollPane();scrollPane_2.setBounds(10, 22, 533, 64);panel_2.add(scrollPane_2);textSend = new JTextArea();textSend.setWrapStyleWord(true);textSend.setLineWrap(true);scrollPane_2.setViewportView(textSend);JButton button_1 = new JButton("群发");button_1.addActionListener(new Button_1ActionListener());button_1.setBounds(307, 86, 93, 23);panel_2.add(button_1);JButton sendMG = new JButton("发送");sendMG.addActionListener(new SendMGActionListener());sendMG.setBounds(432, 86, 93, 23);panel_2.add(sendMG);LOGIN.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) {//连接服务器userString IP=textIP.getText().trim();int port=Integer.parseInt(textPort.getText().trim());String user=textUser.getText().trim();if(ClientMG.getClientMG().Connect(IP,port,user)) {ClientMG.getClientMG().setLogTxt("已经连接到服务器");}else {ClientMG.getClientMG().setLogTxt("连接服务器失败");}}});}private class SendMGActionListener implements ActionListener {public void actionPerformed(ActionEvent e) {//发送信息//1.获取选择的用户名称//2.发送给服务器端含有接收用户信息的交互协议串String SenderName=ClientMG.getClientMG().getClientThd().getName();String RecName=listUser.getSelectedValue().toString();String MSGinfo=textSend.getText().trim();String sMsg="MSG|"+SenderName+"|"+RecName+"|"+MSGinfo;ClientMG.getClientMG().getClientThd().sendMsg(sMsg);//将消息内容显示到聊天记录中//[发送者]//消息内容//清空发送消息框ClientMG.getClientMG().setLogTxt("[我]：");ClientMG.getClientMG().setLogTxt(MSGinfo);textSend.setText("");}}private class Button_1ActionListener implements ActionListener {public void actionPerformed(ActionEvent e) {//群发信息//1.获取选择的用户名称//2.发送给服务器端含有接收用户信息的交互协议串//发送到服务器，MSG|SenderName|RecName|MSGInfoString SenderName=ClientMG.getClientMG().getClientThd().getName();String RecName="ALL";String MSGinfo=textSend.getText().trim();String sMsg="MSG|"+SenderName+"|"+RecName+"|"+MSGinfo;ClientMG.getClientMG().getClientThd().sendMsg(sMsg);//将消息内容显示到聊天记录中//[发送者]//消息内容//清空发送消息框ClientMG.getClientMG().setLogTxt("[我]：");ClientMG.getClientMG().setLogTxt(MSGinfo);textSend.setText("");}}private class BtnCloseActionListener implements ActionListener {public void actionPerformed(ActionEvent e) {//向服务器发送线下信息，OFFLINE|usernameString SenderName=ClientMG.getClientMG().getClientThd().getName();String str="OFFLINE|"+SenderName;ClientMG.getClientMG().getClientThd().sendMsg(str);//清空在线用户列表ClientMG.getClientMG().clearItem();//消息记录中显示断开连接ClientMG.getClientMG().setLogTxt("已经断开连接");}}}

 ClientMG代码：

package GUISocket.chat.Client;import java.net.Socket;public class ClientMG {private static final ClientMG clientmg=new ClientMG();private ClientMG() {}public static ClientMG getClientMG() {return clientmg;}private ClientForm clientWin;public void setClientForm(ClientForm c) {clientWin=c;}public void setLogTxt(String str) {clientWin.textLog.append(str+"\r\n");		}public void addItem(String user) {clientWin.itemUsers.addElement(user);}public void addItems(String[] users) {for(int i=0;i<users.length;i++) {clientWin.itemUsers.addElement(users[i]);}}//所有用户列表清空public void clearItem() {clientWin.itemUsers.clear();}//删除一个用户public void removeItem(String str) {clientWin.itemUsers.removeElement(str);}SocketThread sthd;public boolean Connect(String IP,int port,String user) {Socket socket=null;try {socket=new Socket(IP,port);sthd=new SocketThread(socket, user);sthd.start();return true;} catch (Exception e) {// TODO: handle exceptione.printStackTrace();return false;}}public SocketThread getClientThd() {return sthd;}
}

SocketThread代码：

package GUISocket.chat.Client;import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;public class SocketThread extends Thread{BufferedReader br=null;PrintWriter pw=null;Socket socket=null;public SocketThread(Socket socket,String user){super(user);//登录时用的用户名this.socket=socket;}public void run() {try {br=new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));pw=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(),"UTF-8")));String sLOGIN="LOGIN|"+this.getName();sendMsg(sLOGIN);String str="";while((str=br.readLine())!=null) {String[] commands=str.split("\\|");if(commands[0].equals("USERLISTS")) {//USERLISTS|user1_user2_user3String[] sUsers=commands[1].split("\\_");ClientMG.getClientMG().addItems(sUsers);}else if(commands[0].equals("ADD")) {//ADD|UserNameString sNewUser=commands[1];ClientMG.getClientMG().addItem(sNewUser);}else if(commands[0].equals("MSG")) {//格式 MSG|SenderName|MSGinfoString SenderName=commands[1];String MSGinfo=commands[2];//将消息内容显示到聊天记录中//[发送者]//消息内容ClientMG.getClientMG().setLogTxt("["+SenderName+"]");ClientMG.getClientMG().setLogTxt(MSGinfo);}else if(commands[0].equals("DEL")) {//3.处理下线用户信息，DEL|username//删除用户列表中的usernameString sUser=commands[1];ClientMG.getClientMG().removeItem(sUser);ClientMG.getClientMG().setLogTxt(sUser+"下线了。");}else if(commands[0].equals("CLOSE")) { //CLOSE//1.处理CLOSE命令，界面显示服务器关闭//2。清空在线用户列表ClientMG.getClientMG().clearItem();ClientMG.getClientMG().setLogTxt("服务器关闭");//3.关闭ClientChatbreak;}//ClientMG.getClientMG().setLogTxt(str);}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}finally {try {if(pw!=null)pw.close();if(br!=null)br.close();if(socket!=null)socket.close();} catch (Exception e2) {// TODO: handle exception}}}public void sendMsg(String str) {pw.println(str);pw.flush();}
}

ServerForm代码：

package GUISocket.chat.Server;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.EventQueue;import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;
import javax.swing.ScrollPaneConstants;
import javax.swing.border.EmptyBorder;import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;public class ServerForm extends JFrame {/*** */private JPanel contentPane;public JTextArea textLog;private JTextField textPort;public static void main(String[] args) {EventQueue.invokeLater(new Runnable() {public void run() {try {ServerForm frame = new ServerForm();frame.setVisible(true);ServerMG.getServerMG().setServerForm(frame);} catch (Exception e) {e.printStackTrace();}}});}public ServerForm() {setTitle("多人聊天服务器");setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);setBounds(100, 100, 510, 566);contentPane = new JPanel();contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));setContentPane(contentPane);contentPane.setLayout(null);JLabel lblNewLabel = new JLabel("配置信息");lblNewLabel.setBounds(20, 10, 54, 15);contentPane.add(lblNewLabel);JLabel label = new JLabel("端口:");label.setBounds(30, 34, 39, 15);contentPane.add(label);textPort = new JTextField();textPort.setText("8900");textPort.setBounds(65, 31, 66, 21);contentPane.add(textPort);textPort.setColumns(10);JButton btnStart = new JButton("开启服务");btnStart.addActionListener(new BtnStartActionListener());btnStart.setBounds(180, 30, 93, 23);contentPane.add(btnStart);JButton btnClose = new JButton("关闭服务");btnClose.addActionListener(new BtnCloseActionListener());btnClose.setBounds(325, 30, 93, 23);contentPane.add(btnClose);JPanel panel = new JPanel();panel.setBounds(10, 10, 474, 54);contentPane.add(panel);panel.setLayout(null);JLabel label_1 = new JLabel("消息记录");label_1.setBounds(10, 94, 54, 15);contentPane.add(label_1);JPanel panel_1 = new JPanel();panel_1.setBounds(0, 81, 474, 436);contentPane.add(panel_1);panel_1.setLayout(null);JScrollPane scrollPane = new JScrollPane();scrollPane.setBounds(10, 41, 464, 368);panel_1.add(scrollPane);scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);textLog = new JTextArea();textLog.setLineWrap(true);textLog.setWrapStyleWord(true);scrollPane.setViewportView(textLog);}private class BtnCloseActionListener implements ActionListener {public void actionPerformed(ActionEvent e) {}}private class BtnStartActionListener implements ActionListener {public void actionPerformed(ActionEvent e) {//开启服务int port=Integer.parseInt(textPort.getText().trim());if(ServerMG.getServerMG().CreateServer(port)) {ServerMG.getServerMG().setLogTxt("服务器开启...");}else {ServerMG.getServerMG().setLogTxt("服务器开启失败...");}}}
}

ServerListener代码：

package GUISocket.chat.Server;import java.net.ServerSocket;
import java.net.Socket;public class ServerListener extends Thread{Socket socket=null;ServerSocket server=null;public ServerListener(ServerSocket server) {this.server=server;}public void run() {try {while(true) {socket=server.accept();ServerMG.getServerMG().setLogTxt("客户端： "+socket);		new SocketThread(socket).start();}} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}}

ServerMG代码：

package GUISocket.chat.Server;import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;import javax.swing.JTextArea;public class ServerMG {private static final ServerMG servermg=new ServerMG();private ServerMG() {}public static ServerMG getServerMG() {return servermg;}//主界面的操作private ServerForm serverWin;//将窗体对象注册到管理类当中public void setServerForm(ServerForm s) {serverWin=s;}//设置主界面public void setLogTxt(String str) {serverWin.textLog.append(str+"\r\n");}private ServerSocket server;public boolean CreateServer(int port) {try {			server=new ServerSocket(port);new ServerListener(server).start();return true;} catch (Exception e) {// TODO: handle exceptione.printStackTrace();return false;}}public void CloseServer() {try {//1.向所有在线用户发送关闭服务器的信息，CLOSEsendClosetoAll();//2.遍历Arraylist将其中的每一个ServerChat关闭closeAllThread();//3.ArrayList要清空clearList();//4.关闭ServerListener//5.关闭ServerSocketserver.close();} catch (Exception e) {// TODO: handle exceptione.printStackTrace();}}//ArrayList操作ArrayList<SocketThread> a1OnlineList=new ArrayList<>();//存放所有和public synchronized void addList(SocketThread sc) {//限制重名a1OnlineList.add(sc);}public void clearList() {a1OnlineList.clear();}public synchronized void removeList(SocketThread sc) {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);if(s.equals(sc)) {a1OnlineList.remove(sc);break;}}}//信息的管理public void getOnlineNames(SocketThread sc) {//非第1次登录时，得到所有的在线用户if(a1OnlineList.size()>0) {String sUsers="";//给客户端，USERLISTS|user1_user2_user3for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);sUsers+=s.getName()+"_";}sc.sendMsg("USERLISTS|"+sUsers);}}public void sendNewUsertoAll(SocketThread sc) {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);s.sendMsg("ADD|"+sc.getName());}}//通过Mame用户名查找目标public SocketThread getSocketThreadByName(String sName) {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);if(s.getName().equals(sName)) {return s;}}return null;}//发送给所有人，但是要排除自身public void sendMsgtoAll(String sMsg,SocketThread sc) {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);if(!s.equals(sc)) {s.sendMsg(sMsg);}}}public void sendOfflieUsertoAll(SocketThread sc) {//向所有的其他在线用户发送用户下线信息，DE|usernamefor(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);if(!s.equals(sc)) {s.sendMsg("DEL|"+sc.getName());}}}public void sendClosetoAll() {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);s.sendMsg("CLOSE");}}public void closeAllThread() {for(int i=0;i<a1OnlineList.size();i++) {SocketThread s=a1OnlineList.get(i);s.closeChat();}}}

SocketThread代码：

package GUISocket.chat.Server;import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.Socket;public class SocketThread extends Thread{BufferedReader br=null;PrintWriter pw=null;Socket socket=null;public SocketThread(Socket socket) {this.socket = socket;}public void run() {try {br=new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));pw=new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream(),"UTF-8")));String str="";while((str=br.readLine())!=null) {//循环响应客户的发送信息//接受客户端发过来的信息String [] commands=str.split("\\|");if(commands[0].equals("LOGIN")) {//解析登录请求，格式，LOGIN|UserNameString sUSER=commands[1];this.setName(sUSER);//将用户名信息放入Threadname中//1.得到所有在线用户信息名称，发回客户端：USERLISTS|user1_user2_user3ServerMG.getServerMG().getOnlineNames(this);//2.将当前登录用户的信息(用户名),发送给已经在线的其他用户，ADD|userNameServerMG.getServerMG().sendNewUsertoAll(this);//3.将当前登录的Socket信息放入ArrayList中ServerMG.getServerMG().addList(this);}else if(commands[0].equals("MSG")) {//格式：MSG|SenderName|RecName|MSGoinfoString SenderName=commands[1];String RecName=commands[2];String MSGinfo=commands[3];//群聊if(RecName.equals("ALL")) {String sMsg="MSG!"+SenderName+"|"+MSGinfo;//格式：MSG|SenderName|MSGinfoServerMG.getServerMG().sendMsgtoAll(sMsg,this);ServerMG.getServerMG().setLogTxt(SenderName+"发送信息["+MSGinfo+"]到所有人。");}//私聊else {//通过RecName用户名查找，找到目标SocketThreadSocketThread sc=ServerMG.getServerMG().getSocketThreadByName(RecName);if(sc!=null) {//目标对象发送信息，MSG|SenderName|MSGinfoString sMsg="MSG!"+SenderName+"|"+MSGinfo;sc.sendMsg(sMsg);//写入信息日志ServerMG.getServerMG().setLogTxt(SenderName+"发送信息["+MSGinfo+"]到"+RecName);}}}else if(commands[0].equals("OFFLINE")) {//1.创建OFFLINEString sUser=commands[1];//获取下线的用户名//2.向所有的其他在线用户发送用户下线信息，DEL|usernameServerMG.getServerMG().sendOfflieUsertoAll(this);//3.清除ArrayList中的当前用户信息()socketChatServerMG.getServerMG().removeList(this);//用户下线需后要退出监听用的while循环ServerMG.getServerMG().setLogTxt(sUser+"下线了");break;}}} catch (Exception e) {e.printStackTrace();}finally {try {if(pw!=null)pw.close();if(br!=null)br.close();if(socket!=null)socket.close();} catch (Exception e2) {// TODO: handle exception}}}public void closeChat() {try {if(pw!=null)pw.close();if(br!=null)br.close();if(socket!=null)socket.close();} catch (Exception e) {e.printStackTrace();}}public void sendMsg(String str) {pw.println(str);pw.flush();}
}

运行结果如下：

缺点：只能发单行信息，如发多行，需用到base4.