Spring Boot - Service Components

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 −

pubpc interface ProductService {
}

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

@Service
pubpc 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.tutorialspoint.demo.service;

import java.util.Collection;
import com.tutorialspoint.demo.model.Product;

pubpc interface ProductService {
   pubpc abstract void createProduct(Product product);
   pubpc abstract void updateProduct(String id, Product product);
   pubpc abstract void deleteProduct(String id);
   pubpc 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.tutorialspoint.demo.service;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import org.springframework.stereotype.Service;
import com.tutorialspoint.demo.model.Product;

@Service
pubpc 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
   pubpc void createProduct(Product product) {
      productRepo.put(product.getId(), product);
   }
   @Override
   pubpc void updateProduct(String id, Product product) {
      productRepo.remove(id);
      product.setId(id);
      productRepo.put(id, product);
   }
   @Override
   pubpc void deleteProduct(String id) {
      productRepo.remove(id);

   }
   @Override
   pubpc 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.tutorialspoint.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.tutorialspoint.demo.model.Product;
import com.tutorialspoint.demo.service.ProductService;

@RestController
pubpc class ProductServiceController {
   @Autowired
   ProductService productService;

   @RequestMapping(value = "/products")
   pubpc ResponseEntity<Object> getProduct() {
      return new ResponseEntity<>(productService.getProducts(), HttpStatus.OK);
   }
   @RequestMapping(value = "/products/{id}", method = RequestMethod.PUT)
   pubpc 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)
   pubpc 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)
   pubpc 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.tutorialspoint.demo.model;

pubpc class Product {
   private String id;
   private String name;

   pubpc String getId() {
      return id;
   }
   pubpc void setId(String id) {
      this.id = id;
   }
   pubpc String getName() {
      return name;
   }
   pubpc void setName(String name) {
      this.name = name;
   }
}

A main Spring Boot apppcation is given below −

package com.tutorialspoint.demo;

import org.springframework.boot.SpringApppcation;
import org.springframework.boot.autoconfigure.SpringBootApppcation;

@SpringBootApppcation
pubpc class DemoApppcation {
   pubpc static void main(String[] args) {
      SpringApppcation.run(DemoApppcation.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.tutorialspoint</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:  ecppse 
apply plugin:  org.springframework.boot 

group =  com.tutorialspoint 
version =  0.0.1-SNAPSHOT 
sourceCompatibipty = 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 apppcation 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/pbs directory.

Run the JAR file by using the command given below −

java –jar <JARFILE> 

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

Now hit the below URL’s in POSTMAN apppcation 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