How to configure port for a Spring Boot application

You can set that in application.properties under /src/main/resources/

server.port = 8090

"**server.port=8080**" will only works if your running application as a jar through main method,

This configuration will not work if your running this application as a war file through tomcat container.

If you are going to run apps as jar file in command environment, just type "SERVER_PORT=*** " as prefix. The full command to execute will look like below:

SERVER_PORT=8080 java -jar ***.jar
If you wanna run app in background in Linux, command with 'nohup' will look like below:

SERVER_PORT=8080 nohup java -jar ***.jar &

The default port is : 8080 but we can customize the port number in application.properties
as shown below


spring.mvc.view.prefix=/WEB-INF/jsp/
spring.mvc.view.suffix=.jsp
server.port = 5050 -- #here we can give any port number.

In `application.properties` file present in resources:

server.port=8082

Just have a `application.properties` in `src/main/resources` of the project and give there

server.port=****
where `****` refers to the port number.

This worked for me :

Added a custom container class :

@Component
public class CustomContainer implements EmbeddedServletContainerCustomizer {

@Override
public void customize(ConfigurableEmbeddedServletContainer configurableEmbeddedServletContainer) {
configurableEmbeddedServletContainer.setPort(8888);
}

}

But this was still not using port 8888.

Then I set "scanBasePackages" property like this on "@SpringBootApplication" class on my main method: `(scanBasePackages = {"custom container package"})`

@SpringBootApplication(scanBasePackages = {"com.javabrains.util"})
public class CourseApiApp {

public static void main (String args []) {
SpringApplication.run(CourseApiApp.class, args);
}
}

And it started picking up port set in Custom Container.

To extend other answers:

There is a section in the docs for testing which explains how to configure the port on integration tests:


- [41.3 Testing Spring Boot applications][1]
- [41.3.3 Working with random ports][2]

---

At integration tests, the port configuration is made using the annotation `@SpringBootTest` and the `webEnvironment` values.

---
### Random port:

@SpringBootTest(webEnvironment=WebEnvironment.RANDOM_PORT)

You can inject the value using `@LocalServerPort` which is the same as `@Value("${local.server.port}")`.

- Example:

Random port test configuration:


@RunWith(SpringRunner.class
@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
public class ExampleTest {
...
@LocalServerPort //to inject port value
int port;
}

---

### Defined port:

@SpringBootTest(webEnvironment=WebEnvironment.DEFINED_PORT)

It takes the value from `server.port` if is defined.

- If is defined using `@TestPropertySource(properties = "server.port=9192")`, it overrides other defined values.
- If not, it takes the value from `src/test/resources/application.properties` (if exists).
- And finally, if it is not defined it starts with the default `8080`.

Example:

Defined port test configuration:

@RunWith(SpringRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.DEFINED_PORT)
@TestPropertySource(properties = "server.port=9192")
public class DemoApplicationTests {

@Test
public void contextLoads() {
}

}


[1]:

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[2]:

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Mostly springboot runs on `port:8080` because of embedded Tomcat. In some it may throw an error `port 8080 already in use`. To avoid this kind of issues we can config the server port.
Using application.properties
-
add `server.port=9898`
On runtime config
-
run your application with below arguments.

`spring-boot:run -Drun.jvmArguments='-Dserver.port=8081'`

1.1 Update via a properties file.

**/src/main/resources/application.properties**

server.port=8888

**Update via a yaml file.**

server:

port: 8888

**EmbeddedServletContainerCustomizer**

@Component
public class CustomContainer implements EmbeddedServletContainerCustomizer {

@Override
public void customize(ConfigurableEmbeddedServletContainer container) {

container.setPort(8888);

}

}