Spring Boot – How to Change Embedded Tomcat default port

By default, the embedded tomcat server of Spring Boot application will be starting at port 8080. In this article, we will learn how to change embedded Tomcat default port using one of the following approaches

1. Using application.properties or application.yml
2. Implementing EmbeddedServletContainerCustomizer interface
3. Using SpringApplication class
4. Change port directly through command line
   

Let’s assume we have a simple Spring Boot Hello World application like below.

Folder Structure:

1. Create a simple Maven Project “SpringBootTutorial” by selecting maven-archetype-quickstart  and create a package for our source files “com.javainterviewpoint” under  src/main/java 
2. Now add the following dependency in the POM.xml

   <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0	http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
   
    <groupId>com.javainterviewpoint</groupId>
    <artifactId>SpringBootTutorial</artifactId>
    <version>0.0.1-SNAPSHOT</version>
   
    <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>1.5.1.RELEASE</version>
    </parent>
    
    <dependencies>
      <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
    </dependencies>
    
    <build>
      <plugins>
        <plugin>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
      </plugins>
    </build>
    </project>

3. Create the Java classes HelloWorld.java under com.javainterviewpoint folder.

The spring-boot-starter-parent is a special starter, it provides useful Maven defaults. Since we are developing a web application, we also need to add spring-boot-starter-web dependency.This will additional dependencies such Tomcat, Jackson, Spring boot etc which are required for our application.

HelloWorld.java

Place HelloWorld.java under com.javainterviewpoint folder

package com.javainterviewpoint;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@EnableAutoConfiguration
@SpringBootApplication
public class HelloWorld {

    @RequestMapping("/")
    String hello() {
        return "Hello World! JavaInterviewPoint";
    }

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

We have added the below annotations in our HelloWorld class

• @RestController – This annotation is a stereotype annotation, this annotation tells spring to render the result back to the caller.
• @RequestMapping – This annotation will any HTTP request with the path “/” should be mapped to the hello() method
• @EnableAutoConfiguration – This annotation tells the Spring Boot to configure the application based on the dependencies added. Since spring-boot-starter-web has added Tomcat and Spring MVC, auto-configuration will setup a web based application.

Upon execution, we will have the application started with the below console

 .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.1.RELEASE)

2017-02-24 15:14:04.568  INFO 1112 --- [           main] com.javainterviewpoint.HelloWorld        : Starting HelloWorld on DA56CZ8VD02 with PID 1112 (C:\Jackson\sts\JIPWorkspace\SpringBootTutorial\target\classes started by xbbl47m in C:\Jackson\sts\JIPWorkspace\SpringBootTutorial)
2017-02-24 15:14:04.570  INFO 1112 --- [           main] com.javainterviewpoint.HelloWorld        : No active profile set, falling back to default profiles: default
2017-02-24 15:14:04.622  INFO 1112 --- [           main] ationConfigEmbeddedWebApplicationContext : Refreshing org.springframework.boot.context.embedded.AnnotationConfigEmbedde[email protected]: startup date [Fri Feb 24 15:14:04 IST 2017]; root of context hierarchy
2017-02-24 15:14:05.432  INFO 1112 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration' of type [class org.springframework.boot.autoconfigure.validation.ValidationAutoConfiguration] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-02-24 15:14:05.533  INFO 1112 --- [           main] trationDelegate$BeanPostProcessorChecker : Bean 'validator' of type [class org.springframework.validation.beanvalidation.LocalValidatorFactoryBean] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2017-02-24 15:14:05.933  INFO 1112 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat initialized with port(s): 8080 (http)
2017-02-24 15:14:05.952  INFO 1112 --- [           main] o.apache.catalina.core.StandardService   : Starting service Tomcat
2017-02-24 15:14:05.953  INFO 1112 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet Engine: Apache Tomcat/8.5.11
2017-02-24 15:14:06.059  INFO 1112 --- [ost-startStop-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2017-02-24 15:14:06.059  INFO 1112 --- [ost-startStop-1] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1439 ms
2017-02-24 15:14:06.206  INFO 1112 --- [ost-startStop-1] o.s.b.w.servlet.ServletRegistrationBean  : Mapping servlet: 'dispatcherServlet' to [/]
2017-02-24 15:14:06.210  INFO 1112 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'characterEncodingFilter' to: [/*]
2017-02-24 15:14:06.210  INFO 1112 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'hiddenHttpMethodFilter' to: [/*]
2017-02-24 15:14:06.210  INFO 1112 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'httpPutFormContentFilter' to: [/*]
2017-02-24 15:14:06.210  INFO 1112 --- [ost-startStop-1] o.s.b.w.servlet.FilterRegistrationBean   : Mapping filter: 'requestContextFilter' to: [/*]
2017-02-24 15:14:06.522  INFO 1112 --- [           main] s.w.s.m.m.a.RequestMappingHandlerAdapter : Looking for @ControllerAdvice: org.springframework.boot.context.embedded.AnnotationConfigEmbedde[email protected]: startup date [Fri Feb 24 15:14:04 IST 2017]; root of context hierarchy
2017-02-24 15:14:06.614  INFO 1112 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/]}" onto java.lang.String com.javainterviewpoint.HelloWorld.hello()
2017-02-24 15:14:06.619  INFO 1112 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error]}" onto public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)
2017-02-24 15:14:06.619  INFO 1112 --- [           main] s.w.s.m.m.a.RequestMappingHandlerMapping : Mapped "{[/error],produces=[text/html]}" onto public org.springframework.web.servlet.ModelAndView org.springframework.boot.autoconfigure.web.BasicErrorController.errorHtml(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
2017-02-24 15:14:06.654  INFO 1112 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/webjars/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-02-24 15:14:06.654  INFO 1112 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-02-24 15:14:06.700  INFO 1112 --- [           main] o.s.w.s.handler.SimpleUrlHandlerMapping  : Mapped URL path [/**/favicon.ico] onto handler of type [class org.springframework.web.servlet.resource.ResourceHttpRequestHandler]
2017-02-24 15:14:06.938  INFO 1112 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-02-24 15:14:07.016  INFO 1112 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-02-24 15:14:07.021  INFO 1112 --- [           main] com.javainterviewpoint.HelloWorld        : Started HelloWorld in 2.832 seconds (JVM running for 3.398)

How to Change Embedded Tomcat default port

We will change embedded tomcat default port from 8080 to 9090

1. Using application.properties or application.yml

Create the application.properties file under “src\main\resources\application.properties” and add the below entry

server.port = 9090

If not create application.yml file under “src\main\resources\application.yml” and add the below entry

server:
       port: 9090

After creating any one of the files, start the spring boot app, you will be able to see that the server has started at 9090 port.

2. Implementing EmbeddedServletContainerCustomizer interface

Embedded Servlet containers port can be changed by implementing the EmbeddedServletContainerCustomizer interface and overriding the customize() method

package com.javainterviewpoint;

import org.springframework.boot.context.embedded.ConfigurableEmbeddedServletContainer;
import org.springframework.boot.context.embedded.EmbeddedServletContainerCustomizer;
import org.springframework.stereotype.Component;

@Component
public class AppContainerCustomizer implements EmbeddedServletContainerCustomizer {
 
    @Override
    public void customize(ConfigurableEmbeddedServletContainer container) 
    {
        container.setPort(9090);
    }
}

3. Using SpringApplication class

package com.javainterviewpoint;

import java.util.HashMap;
import java.util.Map;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@EnableAutoConfiguration
@SpringBootApplication
public class HelloWorld
{

    @RequestMapping("/")
    String hello()
    {
        return "Hello World! JavaInterviewPoint";
    }

    public static void main(String[] args) throws Exception
    {
        //Create object for SpringApplication
        SpringApplication springApplication = new SpringApplication(HelloWorld.class);
        //create a map and add property SERVER_PORT
        Map<String, Object> server = new HashMap<String, Object>();
        server.put("SERVER_PORT", "9090");
        //Overriding the defaults
        springApplication.setDefaultProperties(server);
        //Running our application
        springApplication.run(args);
    }
}

• We have created a new object for the SpringApplication class, passing our HelloWorld.class as an argument.
• Create a new Map and set the value to the property “SERVER_PORT”, pass our map as an argument to the setDefaultProperties() method of the SpringApplication class and run the application.

4. Change port directly through command line

We can also change the embedded tomcat default port directly using java command. While executing the jar through command line we need to add an additional parameter “–server.port=9090”, to change the port to 9090.

java -jar SpringBootTutorial-0.0.1-SNAPSHOT.jar --server.port=9090