java 函数式编程 示例

Welcome to Java Socket programming example. Every server is a program that runs on a specific system and listens on a specific port. Sockets are bound to the port numbers and when we run any server it just listens on the socket and waits for client requests. For example, tomcat server running on port 8080 waits for client requests and once it gets any client request, it responds to them.

欢迎使用Java Socket编程示例。 每个服务器都是在特定系统上运行并在特定端口上侦听的程序。 套接字绑定到端口号，当我们运行任何服务器时，它仅侦听套接字并等待客户端请求。 例如，运行在端口8080上的tomcat服务器等待客户端请求，一旦获得任何客户端请求，它就会响应它们。

Java套接字编程 (Java Socket Programming)

A socket is one endpoint of a two-way communication link between two programs running on the network. The socket is bound to a port number so that the TCP layer can identify the application that data is destined to be sent.

套接字是网络上运行的两个程序之间双向通讯链接的一个端点。 该套接字绑定到一个端口号，以便TCP层可以识别应发送数据的应用程序。

In java socket programming example tutorial, we will learn how to write java socket server and java socket client program. We will also learn how server client program read and write data on the socket.

在Java套接字编程示例教程中，我们将学习如何编写Java套接字服务器和Java套接字客户端程序。 我们还将学习服务器客户端程序如何在套接字上读取和写入数据。

java.net.Socket and java.net.ServerSocket are the java classes that implements Socket and Socket server.

java.net.Socket和java.net.ServerSocket是实现Socket和Socket服务器的Java类。

Java套接字服务器示例 (Java Socket Server Example)

package com.journaldev.socket;import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.ClassNotFoundException;
import java.net.ServerSocket;
import java.net.Socket;/*** This class implements java Socket server* @author pankaj**/
public class SocketServerExample {//static ServerSocket variableprivate static ServerSocket server;//socket server port on which it will listenprivate static int port = 9876;public static void main(String args[]) throws IOException, ClassNotFoundException{//create the socket server objectserver = new ServerSocket(port);//keep listens indefinitely until receives 'exit' call or program terminateswhile(true){System.out.println("Waiting for the client request");//creating socket and waiting for client connectionSocket socket = server.accept();//read from socket to ObjectInputStream objectObjectInputStream ois = new ObjectInputStream(socket.getInputStream());//convert ObjectInputStream object to StringString message = (String) ois.readObject();System.out.println("Message Received: " + message);//create ObjectOutputStream objectObjectOutputStream oos = new ObjectOutputStream(socket.getOutputStream());//write object to Socketoos.writeObject("Hi Client "+message);//close resourcesois.close();oos.close();socket.close();//terminate the server if client sends exit requestif(message.equalsIgnoreCase("exit")) break;}System.out.println("Shutting down Socket server!!");//close the ServerSocket objectserver.close();}}

Java套接字客户端 (Java Socket Client)

package com.journaldev.socket;import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.Socket;
import java.net.UnknownHostException;/*** This class implements java socket client* @author pankaj**/
public class SocketClientExample {public static void main(String[] args) throws UnknownHostException, IOException, ClassNotFoundException, InterruptedException{//get the localhost IP address, if server is running on some other IP, you need to use thatInetAddress host = InetAddress.getLocalHost();Socket socket = null;ObjectOutputStream oos = null;ObjectInputStream ois = null;for(int i=0; i<5;i++){//establish socket connection to serversocket = new Socket(host.getHostName(), 9876);//write to socket using ObjectOutputStreamoos = new ObjectOutputStream(socket.getOutputStream());System.out.println("Sending request to Socket Server");if(i==4)oos.writeObject("exit");else oos.writeObject(""+i);//read the server response messageois = new ObjectInputStream(socket.getInputStream());String message = (String) ois.readObject();System.out.println("Message: " + message);//close resourcesois.close();oos.close();Thread.sleep(100);}}
}

To test java socket programming of server-client communication, first we need to run SocketServerExample class. When you will run socket server, it will just print “Waiting for client request” and then wait for the client request.

要测试服务器与客户端通信的Java套接字编程，首先我们需要运行SocketServerExample类。 当您运行套接字服务器时，它将仅显示“ Waiting for client request”，然后等待客户端请求。

Now when you will run SocketClientExample class, it will send a request to java socket server and print the response message to console.

现在，当您运行SocketClientExample类时，它将向Java套接字服务器发送请求，并将响应消息打印到控制台。

Here is the output of java socket server SocketServerExample program.

这是Java套接字服务器SocketServerExample程序的输出。

Waiting for the client request
Message Received: 0
Waiting for the client request
Message Received: 1
Waiting for the client request
Message Received: 2
Waiting for the client request
Message Received: 3
Waiting for the client request
Message Received: exit
Shutting down Socket server!!

Here is the output of Java socket client SocketClientExample program.

这是Java套接字客户端SocketClientExample程序的输出。

Sending request to Socket Server
Message: Hi Client 0
Sending request to Socket Server
Message: Hi Client 1
Sending request to Socket Server
Message: Hi Client 2
Sending request to Socket Server
Message: Hi Client 3
Sending request to Socket Server
Message: Hi Client exit

That’s all for a quick roundup of Socket programming in java. I hope you can get started with java socket server and java socket client programming.

这就是Java中Socket编程的快速总结。 我希望您可以开始使用Java套接字服务器和Java套接字客户端编程。

Reference: Oracle Doc

参考： Oracle文档

翻译自: https://www.journaldev.com/741/java-socket-programming-server-client

java 函数式编程 示例