这段小代码是因为担任Java助教给刚学习Java的本科大二的小学弟小学妹们指导，他们的实验作业就是编写一个Java聊天室客户端和服务器，为了避免出纰漏，自己事先写了一下。

客户端Ui代码：

package com.CS;import java.awt.BorderLayout;import java.awt.FlowLayout;import java.awt.GridBagLayout;import java.awt.GridLayout;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.JTextField;public class Client_UI extends JFrame{    public JButton Connect;         //创建连接按钮；    public JButton Say;             //创建发送按钮；    public JPanel  Panel;           //创建一个用于存放所有组件的容器；    public JPanel  Panel_up;        //创建一个用于存放界面最上面各个组件的容器；    public JPanel  Panel_down;      //创建一个用于存放界面最下面各个组件的容器；    public JTextField Server_IP;    //用于写IP地址的组件；    public JTextField Server_Port;  //用于写端口号的组件；    public JTextField Say_Send;     //用于写要发送的文字的内容的组件；    public JTextArea  Text_Show;    //用于显示相关信息的组件；        public Client_Thread Server;    //创建一个客户端线程；        public Client_UI(){        Connect=new JButton("Connect");        Say=new JButton("Say");        Server_IP=new JTextField(10);        Server_Port=new JTextField(5);        Say_Send=new JTextField(25);                Text_Show=new JTextArea();        JScrollPane ScrollPane=new JScrollPane();  //使之可以滚动，且设置滚动一直存在；        ScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);        ScrollPane.setViewportView(Text_Show);                        Panel_up=new JPanel();//        Panel_up.setLayout(new GridLayout(1,5));//        Panel_up.setLayout(new FlowLayout(FlowLayout.LEFT));        Panel_up.setLayout(new GridBagLayout());        //布局方法，调试得出该布局方法最合理；        Panel_up.add(new JLabel("Server IP"));        Panel_up.add(Server_IP);        Panel_up.add(new JLabel("Server Port"));        Panel_up.add(Server_Port);        Panel_up.add(Connect);                Panel_down=new JPanel();//        Panel_down.setLayout(new GridLayout(1,3));        Panel_down.setLayout(new FlowLayout(FlowLayout.LEFT));        //布局方法，调试得知，从左边最先开始存放组件。        Panel_down.add(new JLabel("Say"));        Panel_down.add(Say_Send);        Panel_down.add(Say);                Panel=new JPanel();        Panel.setLayout(new BorderLayout());        Panel.add(Panel_up, BorderLayout.NORTH);        Panel.add(ScrollPane);        Panel.add(Panel_down,BorderLayout.SOUTH);                this.setTitle("客户端");        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        this.setSize(400, 300);        this.setLocation(600, 200);        this.add(Panel);        this.setVisible(true);                //对connect按钮增加监听；        Connect.addActionListener(new ActionListener(){            @Override            public void actionPerformed(ActionEvent e) {                Server=new Client_Thread(Client_UI.this);            }        });                //对Say按钮增加监听；        Say.addActionListener(new ActionListener(){            @Override            public void actionPerformed(ActionEvent e) {                Server.SendMessage(Say_Send.getText());                Say_Send.setText("");            }        });    }        public static void main(String args[]){        Client_UI clientui=new Client_UI();    }}

客户端线程代码：

package com.CS;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintStream;//import java.io.PrintWriter;import java.net.Socket;public class Client_Thread extends Thread {    Client_UI UI;    Socket client_socket;    BufferedReader Read;    PrintStream Write;        public Client_Thread(Client_UI ui){        this.UI=ui;        String IP=UI.Server_IP.getText().trim();     //获取IP地址；        int Port=Integer.parseInt(UI.Server_Port.getText().trim());   //获取端口号，并将其转换成int型;        try {            client_socket=new Socket(IP,Port);  //设置连接服务器的IP地址和端口号；            Println("客户端连接服务器成功！");            Read=new BufferedReader(new InputStreamReader(client_socket.getInputStream()));            Write=new PrintStream(client_socket.getOutputStream());        } catch (IOException e) {            Println("客户端连接服务器失败！");            e.printStackTrace();        }                 new Thread(new Runnable(){            @Override            public void run() {                String  message="";                while(true){                    try {                        message=Read.readLine();                    } catch (IOException e) {                        Println("连接服务器中断！");                        e.printStackTrace();                        break;                    }                    if(message!=null&&message.trim()!=""){                        Println(message);                    }                }            }        }).start();    }        public void Println(String s){        if(s!=null){            this.UI.Text_Show.setText(this.UI.Text_Show.getText()+s+"\n");            System.out.println(s + "\n");        }    }        public void SendMessage(String text){        try{            Write.println(text);        }catch(Exception e){            Println(e.toString());        }    }}

服务器UI代码：

package com.Server;import java.awt.BorderLayout;import java.awt.FlowLayout;import java.net.Socket;import java.util.List;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;import javax.swing.JButton;import javax.swing.JFrame;import javax.swing.JLabel;import javax.swing.JPanel;import javax.swing.JScrollPane;import javax.swing.JTextArea;import javax.swing.JTextField;public class Server_UI extends JFrame{    public JButton Start;    public JButton Say;    public JTextField Port_Msg;    public JTextField Say_Msg;    public JPanel Panel_up;    public JPanel Panel;    public JPanel Panel_down;    public JTextArea Text_show;    public Server server;    public List
      
        clients;     //保存服务器接收到的客户端;        public Server_UI(){        Start=new JButton("Start");        Say=new JButton("Say");                Port_Msg=new JTextField(25);        Say_Msg=new JTextField(25);                Text_show=new JTextArea();        JScrollPane ScrollPane=new JScrollPane();        ScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);        ScrollPane.setViewportView(Text_show);                Panel_up=new JPanel();        Panel_up.setLayout(new FlowLayout());        Panel_up.add(new JLabel("Port"));        Panel_up.add(Port_Msg);        Panel_up.add(Start);                Panel_down=new JPanel();        Panel_down.setLayout(new FlowLayout());        Panel_down.add(new JLabel("Say"));        Panel_down.add(Say_Msg);        Panel_down.add(Say);                Panel=new JPanel();        Panel.setLayout(new BorderLayout());        Panel.add(Panel_up, BorderLayout.NORTH);        Panel.add(ScrollPane,BorderLayout.CENTER);        Panel.add(Panel_down,BorderLayout.SOUTH);                this.setTitle("服务器");        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        this.setSize(400, 300);        this.setLocation(100, 200);        this.add(Panel);        this.setVisible(true);                //设置Start监听器；        Start.addActionListener(new ActionListener(){            @Override            public void actionPerformed(ActionEvent e) {                server=new Server(Server_UI.this);            }        });                //设置Say监听器;        Say.addActionListener(new ActionListener(){            @Override            public void actionPerformed(ActionEvent e) {                server.Send_Message(Say_Msg.getText());                Say_Msg.setText("");            }        });    }        public static void main(String args[]){        Server_UI serverUI=new Server_UI();    }}
      

服务器线程代码：

package com.Server;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.PrintStream;import java.io.PrintWriter;import java.net.ServerSocket;import java.net.Socket;import java.util.ArrayList;public class Server extends Thread{    Server_UI ui;    BufferedReader Read;    PrintStream  Write;    ServerSocket server;    public Server(Server_UI UI){        this.ui=UI;        //设置服务器的端口；        int port=Integer.parseInt(ui.Port_Msg.getText().trim());        try {            server=new ServerSocket(port);            Println("端口设置成功！");        } catch (IOException e) {            Println("端口设置失败！");            e.printStackTrace();        }        this.ui.clients=new ArrayList
      
       ();                //创建一个线程，用来等待客户端的连接；        new Thread(new Runnable(){            @Override            public void run() {                    while(true){                        Println("等待客户端接入...");                        Socket Client = null;                        try {                            Client = server.accept();                            ui.clients.add(Client);                            Println("成功连接到客户端"+Client.toString());                            new ListenClient(ui,Client);                        } catch (IOException e) {                            Println("连接客户端失败！");                            Println(Client.toString());                            e.printStackTrace();                        }                    }                                }        }).start();    }        public synchronized void Send_Message(String s){        for(int i=0;i