Service Components are the class file which contains @Service annotation. These class files are used to write business logic in a different layer, separated from @RestController class file. The logic for creating a service component class file is shown here −

public interface ProductService {}

The class that implements the Interface with @Service annotation is as shown −

@Servicepublic class ProductServiceImpl implements ProductService {}

Observe that in this tutorial, we are using Product Service API(s) to store, retrieve, update and delete the products. We wrote the business logic in @RestController class file itself. Now, we are going to move the business logic code from controller to service component.

You can create an Interface which contains add, edit, get and delete methods using the code as shown below −

package com.tecklearn.demo.service; import java.util.Collection;import com.tecklearn.demo.model.Product; public interface ProductService { public abstract void createProduct(Product product); public abstract void updateProduct(String id, Product product); public abstract void deleteProduct(String id); public abstract Collection<Product> getProducts();}

The following code will let you to create a class which implements the ProductService interface with @Service annotation and write the business logic to store, retrieve, delete and updates the product.

package com.tecklearn.demo.service; import java.util.Collection;import java.util.HashMap;import java.util.Map;import org.springframework.stereotype.Service;import com.tecklearn.demo.model.Product; @Servicepublic class ProductServiceImpl implements ProductService { private static Map<String, Product> productRepo = new HashMap<>(); static { Product honey = new Product(); honey.setId(“1”); honey.setName(“Honey”); productRepo.put(honey.getId(), honey); Product almond = new Product(); almond.setId(“2”); almond.setName(“Almond”); productRepo.put(almond.getId(), almond); } @Override public void createProduct(Product product) { productRepo.put(product.getId(), product); } @Override public void updateProduct(String id, Product product) { productRepo.remove(id); product.setId(id); productRepo.put(id, product); } @Override public void deleteProduct(String id) { productRepo.remove(id); } @Override public Collection<Product> getProducts() { return productRepo.values(); }}

The code here show the Rest Controller class file, here we @Autowired the ProductService interface and called the methods.

package com.tecklearn.demo.controller; import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.HttpStatus;import org.springframework.http.ResponseEntity;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestBody;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.RestController; import com.tecklearn.demo.model.Product;import com.tecklearn.demo.service.ProductService; @RestControllerpublic class ProductServiceController { @Autowired ProductService productService; @RequestMapping(value = “/products”) public ResponseEntity<Object> getProduct() { return new ResponseEntity<>(productService.getProducts(), HttpStatus.OK); } @RequestMapping(value = “/products/{id}”, method = RequestMethod.PUT) public ResponseEntity<Object> updateProduct(@PathVariable(“id”) String id, @RequestBody Product product) { productService.updateProduct(id, product); return new ResponseEntity<>(“Product is updated successsfully”, HttpStatus.OK); } @RequestMapping(value = “/products/{id}”, method = RequestMethod.DELETE) public ResponseEntity<Object> delete(@PathVariable(“id”) String id) { productService.deleteProduct(id); return new ResponseEntity<>(“Product is deleted successsfully”, HttpStatus.OK); } @RequestMapping(value = “/products”, method = RequestMethod.POST) public ResponseEntity<Object> createProduct(@RequestBody Product product) { productService.createProduct(product); return new ResponseEntity<>(“Product is created successfully”, HttpStatus.CREATED); }}

The code for POJO class – Product.java is shown here −

package com.tecklearn.demo.model; public class Product { private String id; private String name; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; }}

A main Spring Boot application is given below −

package com.tecklearn.demo; import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplicationpublic class DemoApplication { public static void main(String[] args) { SpringApplication.run(DemoApplication.class, args); }}

The code for Maven build – pom.xml is shown below −

<?xml version = “1.0” encoding = “UTF-8”?><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.tecklearn</groupId> <artifactId>demo</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>demo</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.8.RELEASE</version> <relativePath/> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> </properties> <dependencies> <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> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>

The code for Gradle Build – build.gradle is shown below −

buildscript { ext { springBootVersion = ‘1.5.8.RELEASE’ } repositories { mavenCentral() } dependencies { classpath(“org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}”) }} apply plugin: ‘java’apply plugin: ‘eclipse’apply plugin: ‘org.springframework.boot’ group = ‘com.tecklearn’version = ‘0.0.1-SNAPSHOT’sourceCompatibility = 1.8 repositories { mavenCentral()}dependencies { compile(‘org.springframework.boot:spring-boot-starter-web’) testCompile(‘org.springframework.boot:spring-boot-starter-test’)}

You can create an executable JAR file, and run the Spring Boot application by using the Maven or Gradle commands given below −

For Maven, use the command as shown below −

mvn clean install

After “BUILD SUCCESS”, you can find the JAR file under the target directory.

For Gradle, you can use the command as shown below −

gradle clean build

After “BUILD SUCCESSFUL”, you can find the JAR file under build/libs directory.

Run the JAR file by using the command given below −

java –jar <JARFILE>

Now, the application has started on the Tomcat port 8080 as shown in the image given below −

Now hit the below URL’s in POSTMAN application and you can see the output as shown below −

GET API URL is − http://localhost:8080/products

POST API URL is − http://localhost:8080/products

PUT API URL is − http://localhost:8080/products/3

DELETE API URL is − http://localhost:8080/products/3

So, this brings us to the end of blog. This Tecklearn ‘Service Components in Spring Boot’ blog helps you with commonly asked questions if you are looking out for a job in Java Programming. If you wish to learn Spring Boot and build a career Java Programming domain, then check out our interactive, Java and JEE Training, that comes with 24*7 support to guide you throughout your learning period. Please find the link for course details:

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