Change the port of a Spring boot application without changing the code

Question

I have two applications that I need to run simultaneously, and both are trying to run on port 8080 . I'd like to change one of them to port 9000 . The application I'm trying to change has spring security, so it runs on port 8443 when using https and port 8080 when using http . I have to move it from port 8080 without changing any .java files. Also, I need to run the other application on port 8080 as well, so changing the default tomcat port wouldn't be a good idea.

I tried adding to application.properties the lines server.port=9000 , spring.main.server.port=9000 , then running mvn install , and then java -jar target/app.jar .

I also tried running java -jar target/app.jar with different flags: -Dserver.port=9000 and --server.port=9000 .

Regardless, I get - Tomcat started on port(s): 8443 (https) 8080 (http) .

So, my questions are:

• How do I get it to run on a port different from 8080 ?
• And, what could be causing the configuration files to not change the port?

Answer 1

Run the following command:

mvn spring-boot:run -Drun.jvmArguments='-Dserver.port=8088'

Add the following plugin to your pom.xml file

<build>
    . . . 
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

Answer 2

If you want to change spring boot default port without change any code you should pass port number in spring boot run command as

  java -jar -Dserver.port=8090 hello-spring-boot.jar

Now your application will use 8090 port.

Reference : How to Change the default port in Spring Boot

In Other method we can add server.port property in application.properties file

    server.port = 8090