Spring Boot - Modularizing project into modules and re-use

While working with microservices, there will be many small modules in your systems, they calls each others, for me it would be great if we can share at least the data transfer classes. It will save time on development

Here is the structure of my example

In the example, I created a rest-module-example module, it is the main module which separated into 2 modules ( dto.jar and app.jar )

The rest-module-consumer-example will include the dto.jar ( by Maven or Gradle ) , so It will be easy to consume the REST API

You can find details implementation in the repos below:

rest-module-example: https://github.com/vanduc1102/spring-boot-examples/tree/master/module-rest-example

rest-module-consumer-example: https://github.com/vanduc1102/spring-boot-examples/tree/master/module-rest-consumer-example

Spring Boot override Bootstrap properties

1. Bootstrap properties file is inside the packaged jar

This is not a useful case to manage the bootstrap properties or application properties, the reason is you have to rebuild your application again if made any change to the properties

You should have properties file name following the format bootstrap-{profile}.yml ( or .properties variants)

2. Bootstrap properties is outside of the packaged jar.

I prefer this case to manage properties, we don’t need to rebuild the application again if we made change to properties also we can manage our properties better with VCS like git.

Let assume that we have a configuration file outside of packaged jar.

In order to load the file, we need to change the bootstrap properties location by override the spring.cloud.bootstrap.location attribute.

With this approach we can easily override the bootstrap properties.

Spring Boot Sleuth and ZipKin

This post is my implementation of the post here: https://reflectoring.io/tracing-with-spring-cloud-sleuth/

Although the post already included the source code, but it is still pretty hard for me to start

So I created this post to help me to remember how to make Slueth and Zipkin work.

Spring Cloud Sleuth

will add traceId and spanId to logger

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-sleuth</artifactId>
  <version>${spring-cloud.version}</version>
</dependency>

Analyze Traces with ZipKin

Logger collector and analytics

<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-zipkin</artifactId>
  <version>${spring-cloud.version}</version>
</dependency>

spring.sleuth.sampler.percentage=1.0

Is percentage of sampler, the default value is 0.1 ( 10%) that means you only take 10% of request to sampler

Change to 1.0 ( 100% ) to sample all of request.

Repo URL: https://github.com/vanduc1102/tutorials/tree/master/spring-sleuth

 

Spring Boot 2 - REST template project

Recently, I have a chance to work with Spring Boot, it was pretty hard for me to create Spring project without template that is ready for development. So I created a template to help me save time for next projects.

What are included in this boilerplate:

• Java code format: https://github.com/google/google-java-format


• Maven wrapper version 3.5.4


• Spring Boot version 2.0.5 : https://mvnrepository.com/artifact/org.springframework.boot/spring-boot/2.0.5.RELEASE


• Lombox https://mvnrepository.com/artifact/org.projectlombok/lombok/1.18.2


• Swagger-UI https://mvnrepository.com/artifact/io.springfox/springfox-swagger-ui/2.9.2


• Testing frameworks
  
  
  
  • Spring starter tester: https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html
  
  
  • PowerMock: https://github.com/powermock/powermock
  
  
  • Podam: https://mtedone.github.io/podam/


• Code Jacoco: https://www.jacoco.org/jacoco/trunk/doc/
  
  
  
  • Running command: 

    ./mvnw clean jacoco:prepare-agent install
    

Github Repo: https://github.com/vanduc1102/spring-boot-examples/tree/master/spring-boot-2-rest-service-basic