如何在 Java 中的特定端口创建套接字？
一个套接字是网络上运行的两个程序之间双向通信链路的一个端点。套接字类用于表示客户端程序和服务器程序之间的连接。套接字编程，我们基本上是客户机-服务器编程，其中套接字用作它们之间的链接。我们需要在我们的程序中导入【Java . net】包，该包提供了两个类，即 Socket 类和 ServerSocket 类。套接字类实现连接的客户端，服务器套接字类实现连接的服务器端。
*程序:*
为了创建套接字，需要使用 socket 和 ServerSocket 类导入“【java.net】”包，我们创建该类的对象。
The server opens a ServerSocket on a well-known port and waits for input. At the same time, the client opens a socket with the host name of the server and this well-known port address.* Send a request message to the server to initialize the communication session.
*在服务器端*
import java.net.Socket;
ServerSocket mySsocket= new ServerSocket(portnumber);
*注意:服务器套接字类采用单个参数:端口号。*
在这里，服务器套接字是通过传递一个特定的端口号来监听的。
*在客户端*
import java.net.Socket;
Socket myCsocket= new Socket( address, portnumber);
> 注意:**套接字类采用两个参数，即地址和端口号。
这将向服务器端询问 IP 地址，然后它会在该指定端口上打开到该服务器的套接字。
示例 1: 服务器端
T5】Java
// Java program for creating socket on Server-side
// Server program depicting creation of a socket
// at a specific port
// Importing majorly Socket and ServerSocket class
// from java.net package
import java.net.*;
// Class
public class GFG {
// Main driver method
public static void main(String[] args) throws Exception
{
// Try block to check for exceptions
try {
// Creating an object of ServerSocket class
// with the custom port number - 80
ServerSocket mySsocket = new ServerSocket(80);
// Display commands for better readability
System.out.println("Server started");
System.out.println("Waiting for a client ...");
// Here it will wait for any client which wants
// to get connected to this server
// Establishing a connection
// using accept() method()
Socket socket = mySsocket.accept();
// Display message
System.out.println(
"Client accepted through the port number: "
+ mySsocket.getLocalPort());
// getLocalPort() function returning the port
// number which is being used
}
// Catch block to handle for exceptions
catch (Exception e) {
// Simply return/exit
return;
}
}
}
输出:
Server started
Waiting for a client ...
Client accepted through the port number: 80
示例 2: 客户端
Java
// Java program for creating socket on Client-side
// Client program depicting creation of a socket
// at a specific port
// Importing majorly Socket and ServerSocket class
// from java.net package
import java.net.*;
// Class
public class GFG {
// Main driver method
public static void main(String[] args) throws Exception
{
// Try block to check for exceptions
try {
// Creating an object of Socket class where
// port number same as server side program
Socket myCsocket = new Socket("localhost", 80);
// creating client with local ip address
// port number as '80'
// Display message for better readability
System.out.println("Connected to Server");
}
// Catch block to handle exceptions
catch (Exception e) {
// Simply return and exit the program
return;
}
}
}
输出:
java
Connected to Server**
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