Spring Boot Tutorial
This is a quickstart tutorial for Spring Boot. We will be building out a simple Spring Boot REST example from scratch using Maven.
Spring Boot Tutorial: Getting Started
This tutorial assumes you have Maven installed. If not, please install the latest stable version of Maven. To get started, create a new directory and cd into it. Run the following to create the basic Spring Boot app structure:
mkdir -p src/main/java/webapp
This creates the basic file structure for our Spring Boot project. Now lets add our pom.xml file to the root directory of the project. This file contains the configuration details behind your Maven build, including any required dependencies and plugins for the project. Once created, copy the following into the pom.xml file:
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project>
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework</groupId>
<artifactId>hello-spring-boot</artifactId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
</dependencies>
<properties>
<java.version>1.8</java.version>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
This adds the required dependencies for Spring Boot as well as the Spring Boot Maven plugin.
Creating The REST Controller
To create a sample REST endpoint, we add a Java class with the Spring Boot REST controller annotations. Under the webapp directory, add a WebAppController.java.
WebAppController.java
package webapp;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.bind.annotation.RequestMapping;
@RestController
public class WebAppController {
@RequestMapping("/")
public String mainPage() {
return "Hello World";
}
}
This creates a basic REST endpoint defined by the @RequestMapping("/"). Notice how we define our route /. in the @RequestMapping annotation. We then simply return a string, "Hello World", to the browser.
Creating Spring Boot App
Under the webapp directory, create another java class Application.java.
Application.java
package webapp;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
This creates the launch script for our Spring Boot instance.
Running the App
Navigate to the root of the project and run the following maven command:
mvn clean package
This will build the Spring Boot project using Maven. Once complete, run:
java -jar target/hello-spring-boot-0.1.0.jar
This runs the executable jar file produced by the mvn clean package and stored under the /target directory.
You should see the local port printed in the console. Navigate to the localhost, such as localhost:8080, in the browser. If all went according to plan, you should see the worlds "Hello World" on the screen.
Conclusion
That's it. You've created a basic Spring Boot REST example and run a local instance of the app. You'll probably want to return more than just strings to the browser so remember that there are plenty of template engines for Spring (Thymeleaf) that make rendering client rich web apps a breeze.
great intro