Java HTTP Port Find getPortInRange(int minPort, int maxPort)

Description

Get a free port in supplied port range.

License

Open Source License

Parameter

Parameter	Description
minPort	the minimum port number of the port range to scan.
maxPort	the maximum port number of the port range to scan.

Return

a free socket port.

Declaration

public static String getPortInRange(int minPort, int maxPort) throws java.io.IOException 

Method Source Code

//package com.java2s;
/*//  ww w. j a  v a2s.  co  m
 * Copyright 2005 Sun Microsystems, Inc.
 * Copyright 2005 GigaSpaces, Inc.
 *
 * Licensed 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;

public class Main {
    /**
     * Get a free port in supplied port range. minPort <= freePort <=maxPort The max port should be
     * up to 65536 value.
     *
     * @param minPort the minimum port number of the port range to scan.
     * @param maxPort the maximum port number of the port range to scan.
     * @return a free socket port.
     */
    public static String getPortInRange(int minPort, int maxPort) throws java.io.IOException {
        final int MIN_PORT_LIMIT = 1;
        final int MAX_PORT_LIMIT = 65536;

        if (minPort < 0)
            minPort = MIN_PORT_LIMIT;

        if (maxPort > MAX_PORT_LIMIT)
            maxPort = MAX_PORT_LIMIT;

        IOException ioEx = null;
        for (int i = minPort; i <= maxPort; i++) {
            try {
                return String.valueOf(getPort(i));
            } catch (IOException ex) {
                ioEx = ex;
            }
        }

        throw new IOException("Failed to get free port from supplied port range. minPort: " + minPort + " maxPort: "
                + maxPort + "Reason:" + ioEx);
    }

    /**
     * This method checks whether supplied port is free.
     *
     * If port 0 returns an anonymous port.
     */
    private static int getPort(int port) throws IOException {
        ServerSocket socket = null;

        try {
            socket = new ServerSocket(port);
            return socket.getLocalPort();
        } finally {
            if (socket != null) {
                try {
                    socket.close();
                } catch (IOException ex) {
                    /* don't care */ }
            }
        }
    }
}

Related

1. getPort(final int suggestedPort)
2. getPort(int port)
3. getPort(Proxy proxy)
4. getPort(String endpoint)
5. getPort(String hostAndPort)
6. getPorts(int count)
7. getPorts(int number, int MIN_PORT_NUMBER, int MAX_PORT_NUMBER)
8. getPrometheusMetrics(int metricsPort)
9. getRandomAvailablePort()