Package org.springframework.util

Class SocketUtils

  • public class SocketUtils
extends Object
    Simple utility methods for working with network sockets — for example, for finding available ports on localhost.

    Within this class, a TCP port refers to a port for a ServerSocket; whereas, a UDP port refers to a port for a DatagramSocket.

    Since:
    4.0
    Author:
    Sam Brannen, Ben Hale, Arjen Poutsma, Gunnar Hillert, Gary Russell

    • Constructor Detail

      • SocketUtils

        public SocketUtils()
        Although SocketUtils consists solely of static utility methods, this constructor is intentionally public.

        Rationale

        Static methods from this class may be invoked from within XML configuration files using the Spring Expression Language (SpEL) and the following syntax. 

        <bean id="bean1" ... p:port="#{T(org.springframework.util.SocketUtils).findAvailableTcpPort(12000)}" />
        If this constructor were private, you would be required to supply the fully qualified class name to SpEL's T() function for each usage. Thus, the fact that this constructor is public allows you to reduce boilerplate configuration with SpEL as can be seen in the following example. 
        <bean id="socketUtils" class="org.springframework.util.SocketUtils" />
 <bean id="bean1" ... p:port="#{socketUtils.findAvailableTcpPort(12000)}" />
 <bean id="bean2" ... p:port="#{socketUtils.findAvailableTcpPort(30000)}" />

    • Method Detail

      • findAvailableTcpPort

        public static int findAvailableTcpPort​(int minPort)
        Find an available TCP port randomly selected from the range [minPort, 65535].
        Parameters:
        minPort - the minimum port number
        Returns:
        an available TCP port number
        Throws:
        IllegalStateException - if no available port could be found

      • findAvailableTcpPort

        public static int findAvailableTcpPort​(int minPort,
                                       int maxPort)
        Find an available TCP port randomly selected from the range [minPort, maxPort].
        Parameters:
        minPort - the minimum port number
        maxPort - the maximum port number
        Returns:
        an available TCP port number
        Throws:
        IllegalStateException - if no available port could be found

      • findAvailableTcpPorts

        public static SortedSet<Integer> findAvailableTcpPorts​(int numRequested)
        Find the requested number of available TCP ports, each randomly selected from the range [1024, 65535].
        Parameters:
        numRequested - the number of available ports to find
        Returns:
        a sorted set of available TCP port numbers
        Throws:
        IllegalStateException - if the requested number of available ports could not be found

      • findAvailableTcpPorts

        public static SortedSet<Integer> findAvailableTcpPorts​(int numRequested,
                                                       int minPort,
                                                       int maxPort)
        Find the requested number of available TCP ports, each randomly selected from the range [minPort, maxPort].
        Parameters:
        numRequested - the number of available ports to find
        minPort - the minimum port number
        maxPort - the maximum port number
        Returns:
        a sorted set of available TCP port numbers
        Throws:
        IllegalStateException - if the requested number of available ports could not be found

      • findAvailableUdpPort

        public static int findAvailableUdpPort​(int minPort)
        Find an available UDP port randomly selected from the range [minPort, 65535].
        Parameters:
        minPort - the minimum port number
        Returns:
        an available UDP port number
        Throws:
        IllegalStateException - if no available port could be found

      • findAvailableUdpPort

        public static int findAvailableUdpPort​(int minPort,
                                       int maxPort)
        Find an available UDP port randomly selected from the range [minPort, maxPort].
        Parameters:
        minPort - the minimum port number
        maxPort - the maximum port number
        Returns:
        an available UDP port number
        Throws:
        IllegalStateException - if no available port could be found

      • findAvailableUdpPorts

        public static SortedSet<Integer> findAvailableUdpPorts​(int numRequested)
        Find the requested number of available UDP ports, each randomly selected from the range [1024, 65535].
        Parameters:
        numRequested - the number of available ports to find
        Returns:
        a sorted set of available UDP port numbers
        Throws:
        IllegalStateException - if the requested number of available ports could not be found

      • findAvailableUdpPorts

        public static SortedSet<Integer> findAvailableUdpPorts​(int numRequested,
                                                       int minPort,
                                                       int maxPort)
        Find the requested number of available UDP ports, each randomly selected from the range [minPort, maxPort].
        Parameters:
        numRequested - the number of available ports to find
        minPort - the minimum port number
        maxPort - the maximum port number
        Returns:
        a sorted set of available UDP port numbers
        Throws:
        IllegalStateException - if the requested number of available ports could not be found