关注：CodingTechWork

引言

  在项目开发中，有一个程序是专门给服务下发tcp端口占用的，但是tcp端口有时候会被其他服务给占用，此时端口就会冲突。本文提供一个工具类进行端口占用判断并返回可用端口。

代码

工具类

@Slf4j
public class SocketPortUtil {public static int getNextAvailablePort(int fromPort) throws IOException {ServerSocket serverSocket = null;try {//构建ServerSocketserverSocket = new ServerSocket(fromPort);return serverSocket.getLocalPort();} catch (IOException e) {// port被占用log.info("port={} is not avaiable.", fromPort);} finally {if (serverSocket != null) {serverSocket.close();}}//递归查找下一个可用portreturn getNextAvailablePort(fromPort + 1);}public static void main(String[] args) throws IOException {int port = SocketPortUtil.getNextAvailablePort(64661);System.out.println("next available port is: " + port);}}

测试

通过netstat查找当前服务器被占用的tcp端口，如查看到64661端口被占用，运行上述main函数。测试结果如下：

11:19:06.721 [main] INFO com.test.selfcoding.utils.SocketPortUtil - port=64661 is not avaiable.
next available port is: 64662Process finished with exit code 0