首先,建立一個Server.java的伺服器端類

package socket;
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
/**
 * Created by ljb on 2018-06-10.
 */
public class Server {
    public static void main(String[] args){
        BufferedReader br = null;
 
PrintWriter pw = null;
        try{
            ServerSocket server = new ServerSocket(2000);
Socket socket = server.accept();
//獲取輸入流
br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
//獲取輸出流
pw = new PrintWriter(socket.getOutputStream(),true);
//獲取接收到的資料
String s = br.readLine();
pw.println(s);
 
//列印獲取到的資料
System.out.println(s);
}catch (Exception e){
            e.printStackTrace();
}finally {
            try{
                br.close();
pw.close();
}catch (Exception e){
            }
        }
    }
}

然後建立客戶端類 Client.java

package socket;
import java.io.BufferedReader;
import java.io.InputStreamReader;
 
import java.io.PrintWriter;
import java.net.Socket;
/**
 * Created by ljb on 2018-06-10.
 */
public class Client {
    public static void main(String[] args){
        BufferedReader br = null;
PrintWriter pw = null;
        try{
            Socket socket = new Socket("localhost",2000);
//獲取輸入流與輸出流
br = new BufferedReader(new InputStreamReader(socket.getInputStream()));
pw = new PrintWriter(socket.getOutputStream(),true);
//向伺服器傳送資料
pw.println("hello,world");
String s = null;
            while (true){
                s = br.readLine();
                if(s != null){
                    break;
}
            }
            System.out.println(s);
}catch (Exception e){
            e.printStackTrace();
}finally {
            try{
                br.close();
pw.close();
}catch (Exception e){
            }
        }
    }
}

然後先執行服務端類Server.java,然後再執行Client.java

服務端會收到客戶端傳到的 hello,world 打印出來後,並轉發給客戶端,客戶端也會打印出來