ServerSocket 、Socket 创建Java服务器与客户端以JSON格式聊天

群聊和指定对象的聊天实现

1注意声明为全局变量否则出现空指针

2实现服务器的多连接

3防止断开连接出错，把每个连接用新的线程

new Thread(new Runnable() {
>@Override
public void run() {
try {
    System.out.println("服务器启动");
    server = new ServerSocket(8080);
    sockets = new ArrayList<>();
        while (isRunning) {
                socket = server.accept();
                Thread t = new Thread(new       ServerRead(MyServer.this, socket));
                t.start();
                System.out.println("有客户端连接");
        }
} catch (IOException e1) {
e1.printStackTrace();
}}}).start();

package com.chatOKJSON.android;

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.List;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

import net.sf.json.JSONObject;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JTextArea;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.awt.event.ActionEvent;
import javax.swing.JList;
import javax.swing.JTextField;

public class MyServer extends JFrame {

    private JPanel contentPane;
    private ServerSocket server;
    private Socket socket;
    private JTextArea textArea;
    private OutputStream os;
    private InputStream is;
    public boolean isRunning = true;
    public DefaultListModel<String> model;
    public JList list;
    public HashMap<String, Socket> sockets;

    public boolean isRunning() {
        return isRunning;
    }

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MyServer frame = new MyServer();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * 
     * @param 此方法读
     */

    public void readLine(String line) {
        System.out.println("开始解析这个信息"+line);
        JSONObject obj=JSONObject.fromObject(line);
        String type=obj.getString("type");

        if(type.equals("toSingle")){
            String msg=obj.getString("message");
            String to=obj.getString("to");
            String from=obj.getString("from");
            String time=obj.getString("time");
            Socket toSocket=sockets.get(to);
            System.out.println(toSocket.getInetAddress().getHostAddress());
             OutputStream os;
            try {
                os = toSocket.getOutputStream();
                 BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(os));
                 bw.write(msg+"\n");
                 bw.flush();

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        model.addElement(line);

     }

    /**
     * Create the frame.
     */
    public MyServer() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JButton btnNewButton = new JButton("启动服务器");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                //此线程等待客户端连接
                new Thread(new Runnable() {//匿名内部类

                    @Override
                    public void run() {
                        try {
                            System.out.println("服务器启动");
                            server = new ServerSocket(8080);
                            sockets = new HashMap();
                            while (isRunning) {
                                socket = server.accept();
                                //每一个客户端对应一个线程
                                Thread t = new Thread(new ServerRead(MyServer.this, socket));
                                t.start();
                                sockets.put(socket.getInetAddress().getHostAddress(), socket);
                                System.out.println("有客户端连接");
                            }
                        } catch (IOException e1) {
                            e1.printStackTrace();
                        }

                    }

                }).start();
            }
        });

        btnNewButton.setBounds(278, 10, 128, 77);
        contentPane.add(btnNewButton);

        textArea = new JTextArea();
        textArea.setBounds(22, 167, 241, 69);
        contentPane.add(textArea);

        JButton btnNewButton_1 = new JButton("发送");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                write();
            }
        });
        btnNewButton_1.setBounds(273, 167, 112, 69);
        contentPane.add(btnNewButton_1);

        list = new JList();
        model = new DefaultListModel<>();
        list.setModel(model);
        list.setBounds(23, 10, 241, 149);
        contentPane.add(list);
    }

    public void read(Socket socket) {
        if (socket.isConnected()) {// boolean isConnected()  返回套接字的连接状态。 
            try {
                InputStream is = socket.getInputStream();
                BufferedReader br = new BufferedReader(new InputStreamReader(is));
                String line = br.readLine();
                model.addElement(InetAddress.getLocalHost().getHostName()+""+line);
                System.out.println("服务器收到：" + line);

            } catch (IOException e) {

                e.printStackTrace();
            }
        }else{
            sockets.remove(socket);
        }

    }

    public void write() {
        try {Set<String>set=sockets.keySet();
             Iterator<String>it=set.iterator();
        while(it.hasNext()){

                OutputStream os = socket.getOutputStream();
                BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(os));
                String words = textArea.getText();
                System.out.println("服务器发送信息");
                bw.write(words + "\n");
                bw.flush();
            }
            textArea.setText("");

        } catch (IOException e) {

            e.printStackTrace();
        }

    }
}
**********************************************
package com.chatOKJSON.android;

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

public class ServerRead implements Runnable {
    private MyServer server;
    private Socket socket;

    public ServerRead(MyServer server, Socket socket) {
        this.server = server;
        this.socket = socket;

    }

    @Override
    public void run() {
        InputStream is;
        try {
            is = socket.getInputStream();
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader br = new BufferedReader(isr);
            while (server.isRunning()) {// 别忘记方法的括号
                String line = br.readLine();
                server.readLine(line);
                System.out.println(line);
            }
        } catch (IOException e) {

            e.printStackTrace();
        }

    }
}
****************************************************
package com.chatOKJSON.android;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.border.EmptyBorder;

import net.sf.json.JSONObject;

import javax.swing.DefaultListModel;
import javax.swing.JButton;
import javax.swing.JTextField;
import javax.swing.JList;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Calendar;
import java.awt.event.ActionEvent;
import javax.swing.JTextArea;

public class MyClient extends JFrame {

    private JPanel contentPane;
    private Socket socket;
    private JTextArea textArea;
    private DefaultListModel<String> modle;
    private boolean isRunning=true;
    private JList list;
    private String message;
    private String toIP;
    private JTextField textField;
    public boolean isRunning(){
        return  isRunning;
    }
 /**
 * 
 * @return生成JSON格式的信息，返回要发送信息
 */
    public String creatMessage(){
        message=textArea.getText();
        toIP=textField.getText();
        //String message=textArea.getText();
        JSONObject obj=new JSONObject();
        obj.put("message", message);
        obj.put("type", "toSingle");
        //得到时间Data data=new DAta（）；data.getTime();
        Calendar calendar=Calendar.getInstance();//距1970的毫秒数
        long time=calendar.getTimeInMillis();
        obj.put("time", ""+time);
        obj.put("from", socket.getInetAddress().getHostAddress());
        obj.put("to", toIP);
        System.out.println(obj.toString());
        return  obj.toString();

    }
    /**
     * 将信息发送给服务器
     * msg即为要发送信息
     */

    public void write(String msg){//穿入要发送信息
        try {
            OutputStream os=socket.getOutputStream();
            BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(os));

            bw.write(msg+"\n");
            modle.addElement(message);//聊天窗口添加消息
            textArea.setText("");//消息窗口清空
            bw.flush(); 
        } catch (IOException e) {

            e.printStackTrace();
        }

    }
    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MyClient frame = new MyClient();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public MyClient() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 450, 300);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        textField = new JTextField();
        textField.setBounds(308, 137, 99, 52);
        contentPane.add(textField);
        textField.setColumns(10);

        JButton btnNewButton = new JButton("发送");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                //String toIP =textField.getText();
                String msg=creatMessage();

                write(msg);
            }
        });
        btnNewButton.setBounds(308, 200, 116, 38);
        contentPane.add(btnNewButton);

         list = new JList(); 
        // JScrollPane scrollPane = new JScrollPane(list);

        list.setBounds(28, 10, 252, 179);

        modle=new DefaultListModel<>();   //
        list.setModel(modle);            //
        contentPane.add(list);

        JButton btnNewButton_1 = new JButton("连接服务器");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                try {System.out.println("连接服务器");
                     socket=new Socket("192.168.0.64", 8080);
                     System.out.println("连接完成");
                     //此线程
                    Thread t=new Thread(new ClientRead(MyClient.this));

                    t.start();

                } catch (UnknownHostException e) {

                    e.printStackTrace();
                } catch (IOException e) {

                    e.printStackTrace();
                }

            }
        });
        btnNewButton_1.setBounds(308, 28, 99, 60);
        contentPane.add(btnNewButton_1);

         textArea = new JTextArea();//错误：JTextArea textArea = new JTextArea();
        textArea.setBounds(28, 208, 252, 44);
        contentPane.add(textArea);

    }

    public void read(){
        try {
            InputStream is =socket.getInputStream();
            BufferedReader br=new BufferedReader(new InputStreamReader(is));
            String line=br.readLine();
            modle.addElement("服务器说的"+line);
            System.out.println("服务器："+line);

        } catch (IOException e) {

            e.printStackTrace();
        }

    }

}
***********************************************
package com.chatOKJSON.android;

public class ClientRead implements Runnable {
    private MyClient client;

    public ClientRead(MyClient client) {
        this.client = client;
    }

    @Override
    public void run() {
        while (client.isRunning()) {
            client.read();
        }
    }

}