In this tutorials, I am going to show you how to set or use Spring Boot Random Port in application.

Spring Boot Random Port :

Generally we can set the Spring boot server port by using server.port property in application properties file.

But if we want to set the server port as random port (Generally used when working with micro-services) the server.port should be assigned with ‘0’ (Zero).

So that spring boot will automatically pick the available ports from OS and assigns to the application.

server.port=0

server:
   port:0

Check it :

mvn clean install
mvn spring-boot:run

2018-02-23 06:39:33.449  INFO 10820 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet
.resource.ResourceHttpRequestHandler]
2018-02-23 06:39:33.541  INFO 10820 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework
.web.servlet.resource.ResourceHttpRequestHandler]
2018-02-23 06:39:33.952  INFO 10820 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2018-02-23 06:39:34.236  INFO 10820 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 58535 (http)
2018-02-23 06:39:34.244  INFO 10820 --- [           main] com.onlinetutorialspoint.Application     : Started Application in 8.103 seconds (JVM running for 15.911)

While running the application, we can see (highlighted lines on above) the generated random port in logs.

Reference :

Spring boot Port Config

Happy Learning 🙂