Here you can find the source of getLocalAddress(final String start, final String end)
public static String getLocalAddress(final String start, final String end)
//package com.java2s; /*/*from ww w . j ava 2 s . c o m*/ * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import java.io.IOException; import java.net.ServerSocket; import java.util.Collection; public class Main { public static String getLocalAddress(final String start, final String end) { return start + "localhost:" + getNextAvailablePort() + end; } public static int getNextAvailablePort() { return getNextAvailablePort(new int[] { 0 }); } public static int getNextAvailablePort(final int[] portList) { int port; ServerSocket s = null; try { s = create(portList); port = s.getLocalPort(); } catch (final IOException ioe) { port = -1; } finally { if (s != null) { try { s.close(); } catch (final Throwable e) { //Ignore } } } return port; } public static int getNextAvailablePort(final int min, final int max, final Collection<Integer> excepted) { int port = -1; ServerSocket s = null; for (int i = min; i <= max; i++) { try { s = create(new int[] { i }); port = s.getLocalPort(); if (excepted == null || !excepted.contains(port)) { break; } } catch (final IOException ioe) { port = -1; } finally { if (s != null) { try { s.close(); } catch (final Throwable e) { //Ignore } } } } return port; } private static ServerSocket create(final int[] ports) throws IOException { for (final int port : ports) { try { return new ServerSocket(port); } catch (final IOException ex) { // try next port } } // if the program gets here, no port in the range was found throw new IOException("No free port found"); } }