How to change the port of a Spring Boot application using Gradle?

Question

The simple question is: How can you change the Spring Boot application port with gradle?

---

Here are already listed a lot of correct answers if you are not using gradle. So for none gradle issues, please refere to this post.

Answer 1

In case you don't want to add extra configuration to your Gradle scripts, you can achieve it by setting the SERVER_PORT environment variable:

SERVER_PORT=8888 ./gradlew bootRun

[UPDATE] Since Gradle 4.9, it's possible to pass arguments to bootRun without extra configuration:

./gradlew bootRun --args='--server.port=8888'

Answer 2

If you're not already using the Spring Boot Gradle Plugin add it to your build script (of course, adapt the Spring Boot version to your needs):

buildscript{
    ext { springBootVersion = '1.5.7.RELEASE' }
    dependencies {
          classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
    }
}
apply plugin: 'org.springframework.boot'

With this plugin you can do the following:

bootRun {
    args += ["--server.port=[PORT]"]
}

• obviously, replace [PORT] with the actual port number

OR for more dynamic you can use a project property to change the port. You have to do something similar like this:

if(!project.hasProperty("port"))
    project.ext.set("port", 8080)

bootRun {
    args += ["--server.port=${project.port}"]
}

Then you can start the application with

./gradlew bootRun -Pport=8888

If you skip the -Pport in this example it will use 8080.