Java如何检查端口是否被使用？

在Java编程中，如何扫描打开的端口(是否被使用)？

以下示例显示如何通过创建 Socket 对象来检查主机上打开或正在使用的端口(相当于一个简单的端口扫描器)。

package com.yiibai;

import java.net.*; import java.io.*; public class CheckPort { public static void main(String[] args) { Socket Skt; String host = "localhost"; if (args.length > 0) { host = args[0]; } for (int i = 100; i < 1024; i++) { try { System.out.println("Looking for " + i); Skt = new Socket(host, i); System.out.println("There is a server on port " + i + " of " + host); } catch (UnknownHostException e) { System.out.println("Exception occured" + e); break; } catch (IOException e) { } } } } 

Java

上述代码示例将产生以下结果 -

......
Looking for 133
Looking for 134
Looking for 135
There is a server on port 135 of localhost
Looking for 136
Looking for 137
Looking for 138
......