1.概述

通过ServerSocket与Socket实现的TCP的通信,这个例子配合了swing使用,其实作者之前发过一篇ServerSocker与Socket的通信,在这里,这边文章就是在这个例子上修改而成的.

其实原理很简单的,就是一个服务端一个客户端,服务端这边创建好ServerSocket后,使用accept()堵塞一直等待客户端发送socket.

好吧,不废话了.进正题.

2.服务端

swing的部分就不说了,说一下主要操作.

(1)新建ServerSocket

1ServerSocket serverSocket = null;
2serverSocket = new ServerSocket(12345);//一个不被占用的端口即可

构造方法的参数是端口,默认使用本地ip. ServerSocket有三个构造方法.

1ServerSocket(int port);
2ServerSocket(int port,int backlog);
3ServerSocker(int poer,int backlog,InetAddress ip);

详情可以看这里

(2)接收socket

Socket socket = serverSocket.accept();

返回一个Socket(),会一直等待,处于阻塞状态. 一般设置一个while(true)循环接收.

(3)数据处理

使用DataInputStream与DataOutputStream:

1DataInputStream inputStream = new DataInputStream(socket.getInputStream());
2DataOutputStram outputStream = new DataOutputStream(socket.getOutputStream());

然后使用read与write方法即可. 注意关闭的时候要等输入输出完成后再一起关闭,就是说,不能这样:

1DataInputStream inputStream = new DataInputStream(socket.getInputStream());
2String data = inputStream.readUTF();
3inputStream.close();
4DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
5outputStream.writeUTF("ok");
6outputStream.close();

这样的话getInputStream()没有问题,但是到了getOutputStream()的时候就有问题了,会提示异常: Socket is closed. 所以解决办法就是等输出完之后再一起关闭:

1DataInputStream inputStream = new DataInputStream(socket.getInputStream());
2String data = inputStream.readUTF();
3DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
4outputStream.writeUTF("ok");
5inputStream.close();//等输出完成后再关闭
6outputStream.close();

(4)完整代码Server.java

1import java.io.DataInputStream;
2import java.io.DataOutputStream;
3import java.io.IOException;
4import java.net.InetAddress;
5import java.net.ServerSocket;
6import java.net.Socket;
7import javax.swing.*;
8
9public class Server {
10    public static void main(String[] args)
11    {
12        JFrame frame = new JFrame("Server");
13        JPanel panel = new JPanel();
14        JTextArea text = new JTextArea();
15
16        panel.add(text);
17        frame.setContentPane(panel);
18        frame.setSize(600, 300);
19        frame.setLocationRelativeTo(null);
20        frame.setVisible(true);
21        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
22
23        ServerSocket serverSocket = null;
24        try
25        {
26            serverSocket = new ServerSocket(12345);
27            while (true)
28            {
29                Socket socket = serverSocket.accept();
30                DataInputStream inputStream = new DataInputStream(socket.getInputStream());
31                text.setText(inputStream.readUTF());
32
33                DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
34                outputStream.writeUTF("ok");
35                inputStream.close();
36                outputStream.close();
37                socket.close();
38            }
39        }
40        catch (IOException e)
41        {
42            e.printStackTrace();
43        }
44        finally
45        {
46            try
47            {
48                serverSocket.close();
49            }
50            catch (IOException e)
51            {
52                e.printStackTrace();
53            }
54        }
55    }
56}

3.客户端

客户端的操作就是开启一个Socket,再通过这个socket获取对应的输入输出流就可以了.

(1)新建一个Socket

Socket socket = new Socket("127.0.0.1",12345);//这个端口与服务端的端口对应

Socket有三个构造方法:

1Socket(InetAddress ip,int port);
2Socket(String ip,int port);
3Socket(InetAddress ip,int port,InetAddress localIp,int localPort);
4Socket(String ip,int port,InetAddress localIp,int localPort);

详情可以看这里

(2)输入输出

同样使用DataInputStream与DataOutputStream:

1DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
2DataInputStream inputStream = new DataInputStream(socket.getInputStream());

(3)完整代码Client.java

1import java.io.DataInputStream;
2import java.io.DataOutputStream;
3import java.io.IOException;
4import java.net.Socket;
5
6import javax.swing.*;
7import java.awt.GridLayout;
8public class Client
9{
10    public static void main(String[] args) {
11        JFrame frame = new JFrame();
12        JTextArea text = new JTextArea();
13        JButton send = new JButton();
14        GridLayout layout = new GridLayout(2, 1, 0, 5);
15
16        frame.setTitle("Client");
17        frame.setVisible(true);
18        frame.setLocationRelativeTo(null);
19        frame.setSize(600, 300);
20        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
21        frame.setLayout(layout);
22
23        frame.add(text);
24        frame.add(send);
25        send.setText("send");
26        send.addActionListener(v ->
27        {
28            try
29            {
30                String host = "127.0.0.1";
31                int port = 12345;
32                Socket socket = new Socket(host, port);
33                DataOutputStream outputStream = new DataOutputStream(socket.getOutputStream());
34                outputStream.writeUTF(text.getText());
35
36                DataInputStream inputStream = new DataInputStream(socket.getInputStream());
37                text.setText(inputStream.readUTF());
38                outputStream.close();
39                inputStream.close();
40                socket.close();
41            }
42            catch (IOException e)
43            {
44                e.printStackTrace();
45            }
46        });
47    }
48}

4.测试

先开启服务端,再开启客户端,这里设置了服务端返回给客户端的信息为"ok".