Spring Boot Rest Tutorial

This tutorial series will focus on spring-boot and rest services. We will go over the basics of setting up a spring boot application and implementing rest services on that application.

Prerequisites

• Java version : 1.8
• Maven version 3.1 or greater
• Your favorite IDE

Getting Started

Let’s create a simple maven project and edit the pom.xml to include the spring dependencies.

    
    <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>matt.blog</groupId>
      <artifactId>quote-rest-service</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <name>Project created to learn about spring boot</name>
      <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.1.RELEASE</version>
      </parent>
      <properties>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
      </properties>
      <dependencies>
        <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
      </dependencies>
    </project>

Let’s Talk Dependencies

We have added the spring-boot-starter-parent dependency as a parent project and named a version there of the latest release 1.5.1.RELEASE. At this point we havn’t included any dependencies into our project classpath. To add the required dependency for RESTful services functionality we will need to add the spring-boot-starter-web.

Let’s Add Main Method

Spring applications rely on a SpringApplication.run(Main.class, commandLineArgs) method as the starting point for Spring applications. Let’s add that class now.

    package io.matt.blog;

    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;

    @SpringBootApplication
    public class RestServiceApp {

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

      }

    }
 

Annotations

Spring boot adds the @SpringBootApplication annotation to the main class. The purpose for this annotation is to tell spring at startup to use default configuration and context creation. This single annotation replaces the use of several others shown below:

        @SpringBootConfiguration
        @EnableAutoConfiguration
        @ComponentScan(excludeFilters={@Filter(type=CUSTOM, classes={TypeExcludeFilter.class}), @Filter(type=CUSTOM, classes={AutoConfigurationExcludeFilter.class})})
        @Target(value={TYPE})
        @Retention(value=RUNTIME)
        @Documented
        @Inherited

Now Let’s Run Our Application

With only our pom file and a main method we start our spring boot application running on an embedded tomcat server. We don’t need a web.xml or a spring-context.xml file. To run the application we can simple Run As.. a java application in your IDE or we can execute on the command line mvn spring-boot:run.

To validate that our application is starting up correctly we should see a print out of the following:

  
  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v1.5.1.RELEASE)
 ...Some other logs will be printed but eventually we should see..
2017-02-25 13:52:49.944  INFO 1288 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Registering beans for JMX exposure on startup
2017-02-25 13:52:50.024  INFO 1288 --- [           main] s.b.c.e.t.TomcatEmbeddedServletContainer : Tomcat started on port(s): 8080 (http)
2017-02-25 13:52:50.031  INFO 1288 --- [           main] io.matt.blog.RestServiceApp              : Started RestServiceApp in 2.844 seconds (JVM running for 3.168)

Ping the Server

Once start up has completed we can navigate our browser to the http://localhost:8080 URL. We will get an error page but that is expected.

Summary

At this point we have created a simple spring boot application that doesn’t do anything but demonstrates how to quickly get started with spring boot. In following tutorials we will develop our quote service and demonstrate more features that spring has to offer. Thanks for stopping by!!