How to get local server host and port in Spring Boot?

Question

I'm starting up a Spring Boot application with mvn spring-boot:run.

One of my @Controllers needs information about the host and port the application is listening on, i.e. localhost:8080 (or 127.x.y.z:8080). Following the Spring Boot documentation, I use the server.address and server.port properties:

@Controller
public class MyController {

    @Value("${server.address}")
    private String serverAddress;

    @Value("${server.port}")
    private String serverPort;

    //...

}

When starting up the application with mvn spring-boot:run, I get the following exception:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'myController': Injection of autowired dependencies failed; nested exception is 
org.springframework.beans.factory.BeanCreationException: Could not autowire field: ... String ... serverAddress; nested exception is java.lang.IllegalArgumentException: Could not resolve placeholder 'server.address' in string value "${server.address}"

Both server.address and server.port cannot be autowired.

How can I find out the (local) host/address/NIC and port that a Spring Boot application is binding on?

Answer 1

IP Address

You can get network interfaces with NetworkInterface.getNetworkInterfaces(), then the IP addresses off the NetworkInterface objects returned with .getInetAddresses(), then the string representation of those addresses with .getHostAddress().

Port

If you make a @Configuration class which implements ApplicationListener<EmbeddedServletContainerInitializedEvent>, you can override onApplicationEvent to get the port number once it's set.

@Override
public void onApplicationEvent(EmbeddedServletContainerInitializedEvent event) {
    int port = event.getEmbeddedServletContainer().getPort();
}

Answer 2

You can get port info via

@Value("${local.server.port}")
private String serverPort;

Answer 3

An easy workaround, at least to get the running port, is to add the parameter javax.servlet.HttpServletRequest in the signature of one of the controller's methods. Once you have the HttpServletRequest instance is straightforward to get the baseUrl with this: request.getRequestURL().toString()

Have a look at this code:

@PostMapping(value = "/registration" , produces = "application/json")
public StringResponse register(@RequestBody RequestUserDTO userDTO, 
    HttpServletRequest request) {
request.getRequestURL().toString();
//value: http://localhost:8080/registration
------
return "";
}

Answer 4

One solution mentioned in a reply by @M. Deinum is one that I've used in a number of Akka apps:

object Localhost {

  /**
   * @return String for the local hostname
   */
  def hostname(): String = InetAddress.getLocalHost.getHostName

  /**
   * @return String for the host IP address
   */
  def ip(): String = InetAddress.getLocalHost.getHostAddress

}

I've used this method when building a callback URL for Oozie REST so that Oozie could callback to my REST service and it's worked like a charm

Answer 5

I have just found a way to get server ip and port easily by using Eureka client library. As I am using it anyway for service registration, it is not an additional lib for me just for this purpose.

You need to add the maven dependency first:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    <version>2.2.2.RELEASE</version>
</dependency>

Then you can use the ApplicationInfoManager service in any of your Spring beans.

@Autowired
private ApplicationInfoManager applicationInfoManager;
...

InstanceInfo applicationInfo = applicationInfoManager.getInfo();

The InstanceInfo object contains all important information about your service, like IP address, port, hostname, etc.

Answer 6

To get the port number in your code you can use the following:

@Autowired
Environment environment;

@GetMapping("/test")
String testConnection(){
    return "Your server is up and running at port: "+environment.getProperty("local.server.port");      
}

To understand the Environment property you can go through this Spring boot Environment

Answer 7

For Spring 2

val hostName = InetAddress.getLocalHost().hostName

var webServerPort: Int = 0
@Configuration
class ApplicationListenerWebServerInitialized : ApplicationListener<WebServerInitializedEvent> {
    override fun onApplicationEvent(event: WebServerInitializedEvent) {
        webServerPort = event.webServer.port
    }
}

then you can use also webServerPort from anywhere...

Answer 8

You can get hostname from spring cloud property in spring-cloud-commons-2.1.0.RC2.jar

environment.getProperty("spring.cloud.client.ip-address");
environment.getProperty("spring.cloud.client.hostname");

spring.factories of spring-cloud-commons-2.1.0.RC2.jar

org.springframework.boot.env.EnvironmentPostProcessor=\
org.springframework.cloud.client.HostInfoEnvironmentPostProcessor

Answer 9

I used to declare the configuration in application.properties like this (you can use you own property file)

server.host = localhost
server.port = 8081

and in application you can get it easily by @Value("${server.host}") and @Value("${server.port}") as field level annotation.

or if in your case it is dynamic than you can get from system properties

Here is the example

@Value("#{systemproperties['server.host']}")
@Value("#{systemproperties['server.port']}")

For a better understanding of this annotation , see this example Multiple uses of @Value annotation

Answer 10

@Value("${hostname}")
private String hostname;

At Spring-boot 2.3, The hostname was add as the System Environment Property, and you can check it on /actuator/env