package com.hspedu.TestServerClient;

import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    @Test
    public void startServer() throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080
 
);
        System.out.println("伺服器Server正在監聽8080埠，等待客戶端Client連線...");
        Socket socket = serverSocket.accept();
        System.out.println("伺服器socket的執行型別：" + socket.getClass());

        InputStream inputStream = socket.getInputStream();
        byte[] bytes = new byte[1024];
        int readData = 0;
        
 
while ((readData = inputStream.read(bytes)) != -1) {
            System.out.print(new String(bytes, 0, readData));
        }

//        int readChar = 0;
//        while ((readChar = inputStream.read()) != -1) {
//            System.out.print((char) readChar);
//        }

        inputStream.close();
        socket.close();
        serverSocket.close();
    }
}
 

1、ServerSocket可以通過多個accept建立多個socket連線，可以和多個客戶端連線，高併發；

2、ServerSocket的accept方法監聽建立對應的埠(8080)，阻塞狀態等待client客戶端連線，直至有client客戶端連線繼續執行；

3、建議使用位元組bytes陣列讀取接收客戶端client傳送的資訊，容量最好大於資訊長度，否則容易會出現錯位導致亂碼問題（包括char單位元組讀取）；

package com.hspedu.TestServerClient;

import org.junit.Test;

import java.io.IOException;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.Socket;

public class Client {

    @Test
    public void startClient() throws IOException {
        Socket socket = new Socket(InetAddress.getLocalHost(), 8080);
        System.out.println("客戶端socket = " + socket);

        OutputStream outputStream = socket.getOutputStream();
        outputStream.write("客戶端 >>> 伺服器：hello, server".getBytes());

        outputStream.close();
        socket.close();
        System.out.println("客戶端退出。");
    }
}

1、new Socket(InetAddress.getLocalHost(), 8080)連線本機伺服器的8080埠，返回socket套接字物件；

2、socket套接字物件的getOutputStream獲取客戶端client的輸出流物件。