In this post, we will study how to create a rest API using Spring Boot. We will be using Maven and Spring STS IDE to create a spring boot Project. You can also use eclipse to create a spring boot project.
Creating a Spring Boot Project
To create a new project, click on File -> New -> Spring Starter Project. Fill out information Group, Artifact, Description, etc. Now click on Next and Finish.
After clicking on finish, the project structure will be like this:
In pom.xml, spring-boot-starter-parent will be automatically used as parent and spring-boot-starter as dependency after clicking on the finish. Apart from this, we need to add one more dependency spring-boot-starter-web for web dependencies ( Including embedded tomcat ).
1 2 3 4 | <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId></dependency> |
Complete pom.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 | <?xml version="1.0" encoding="UTF-8"?> xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.3.4.RELEASE</version> <relativePath /> <!-- lookup parent from repository --> </parent> <groupId>com.codekru</groupId> <artifactId>spring-boot-rest</artifactId> <version>0.0.1-SNAPSHOT</version> <name>spring-boot-rest</name> <description>Spring boot Rest Project</description> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build></project> |
Create first REST API
We will create REST API using @RestController annotation.
Create Model Class
First we will create a package com.codekru.model and create our model class Person.Java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | package com.codekru.model;public class Person { private String firstName; private String lastName; private int age; public Person() { super(); } public Person(String firstName, String lastName, int age) { super(); this.firstName = firstName; this.lastName = lastName; this.age = age; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public int getAge() { return age; } public void setAge(int age) { this.age = age; }} |
First we will create a package com.codekru.model and create our model class Person.Java
Create Controller Class
Now we will create a package com.codekru.controller and will create our rest controller there.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | package com.codekru.controller;import java.util.ArrayList;import java.util.List;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import com.codekru.model.Person;@RestControllerpublic class PersonController { @RequestMapping("/") public List<Person> getPersonList() { List<Person> persons = new ArrayList<>(); persons.add(new Person("Mohan", "tyagi", 20)); persons.add(new Person("Raman", "Chhabra", 28)); return persons; }} |
@RestController -> This annotation will expose this URL as rest API. @RestController is a combination of @Controller and @ResponseBody annotation.
@RequestMapping -> This is the annotation in which specified URI mapping at which this rest API will be exposed.
We will run this application using Application.java
1 2 3 4 5 6 7 8 9 10 11 12 13 | package com.codekru;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplicationpublic class Application { public static void main(String[] args) { SpringApplication.run(Application.class, args); }} |
We have not used @ComponentScan annotation at the Application class intentionally. This is not needed as the @RestController class is in one of the sub-packages of the Application class.
After running the application we can test it at URL: http://localhost:8080/
I have access to this URL using postman and the sample output is given below:
In this tutorial, we have learned how to create a rest API using spring boot. Hope you find this article useful… 🙂 Feel free to contact me with any questions!