Java Socket getLocalPort() 方法

2025 年 3 月 25 日 | 阅读 2 分钟

Java Socket 类的 getLocalPort() 方法返回已绑定到指定套接字的本地端口号。如果套接字正在关闭，则此方法将在套接字关闭后返回连接的端口号。

语法

参数

不适用

getLocalPort() 方法要么返回套接字连接到的本地端口号，要么在套接字未绑定时返回 -1。

示例 1

import java.io.IOException;
import java.net.*;
public class JavaSocketGetLocalPortExample1  {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName(null);
      //the port should be greater or equal to 0, else it will throw an error
        int port=1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //getLocalPort() method returns the port number of the socket
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Port number: 1085

示例 2

import java.io.IOException;
import java.net.*;
public class JavaSocketGetLocalPortExample2  {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
        //getLocalPort() method returns the port number of the socket
      //returns -1 if the socket is not bounded
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Port number: -1

示例 3

import java.io.IOException;
import java.net.*;
public class JavaSocketGetLocalPortExample3  {
    public static void main(String[] args) throws IOException {
      Socket socket = new Socket();
      InetAddress inetAddress=InetAddress.getByName(null);
      //the port should be greater or equal to 0, else it will throw an error
        //passing negative port number
        int port=-1085;
        //calling the constructor of the SocketAddress class
        SocketAddress socketAddress=new InetSocketAddress(inetAddress, port);
        //binding the  socket with the inetAddress and port number
        socket.bind(socketAddress);
        //getLocalPort() method returns the port number of the socket
        System.out.println("Port number: "+socket.getLocalPort());
    }
}

输出

Exception in thread "main" java.lang.IllegalArgumentException: port out of range:-1085
	at java.net.InetSocketAddress.checkPort(InetSocketAddress.java:143)
	at java.net.InetSocketAddress.(InetSocketAddress.java:188)
	at com.tpointtech.JavaSocketGetLocalPortExample3.main(JavaSocketGetLocalPortExample3.java:13)

下一主题Java Socket 类

Java Socket getLocalPort() 方法

语法

参数

返回

示例 1

示例 2

示例 3

联系信息

关注我们

教程

面试题

在线编译器

Python

Java

.Net Framework

AI, ML and Data Science

Cloud Technology

B.Tech and MCA

Web Technology

PHP

Software Testing

Technical Interview

Java Interview

Python

Web Interview

Database Interview

B.Tech / MCA

Important Interview

Software Testing Interview

Company Interviews

Online Compilers

Multiple Choice Questions

Java String 方法

Java 数组类

Java Math 方法

ArrayList 方法

Java List 方法

Java 线程方法

Java Date 类

Java Collection 方法

Java ListIterator 类

Java NIO 教程

HttpURLConnection

Java Deque

Java HttpCookie 类

Java URL 类

Java Vector 类

Java Socket 类

Java Executors

Java Integer 类

Java IdentityHashMap

Java ArrayBlockingQueue

Java Timestamp

Java Spliterator

Java Bitset

Java Instant

Java Compiler 类

Java AtomicInteger 类

Java AtomicLong 方法

Java Authenticator

Java BigDecimal 类

Big Integer 类

Java Boolean 类

Java Byte Class

Java Class

Java Collections 类

CopyOnWriteArrayList

LinkedBlockingDeque

Java Long 类

LinkedTransferQueue

Java List

Java MulticastSocket

Java Number 类

Java Phaser 类

Java Socket getLocalPort() 方法

语法

参数

返回

示例 1

示例 2

示例 3

相关帖子

Socket isClosed()

Socket 类

Socket getPort()

Socket bind()

Socket setSendBufferSize()

Socket shutdownOutput()

Socket getChannel()

Socket connect()

Socket getReuseAddress()

Socket getSendBufferSize()