Spring Boot Microservices — Part1 — Eureka Discivery Service

In this example, I’ll show you how to make the use of Spring Cloud NetFlix Eureka Server to register the microservices.

In this example, I’ve registered two microservices namely product-service and order-service. Please make sure to start two instances of each microservice.

product-service

pom.xml

<?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 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>2.6.7</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>demo</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>demo</name>
   <description>Demo project for Spring Boot</description>

   <properties>
      <java.version>11</java.version>
      <spring-cloud.version>2021.0.2</spring-cloud.version>
   </properties>

   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-actuator</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-mongodb</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
      </dependency>

      <dependency>
         <groupId>org.projectlombok</groupId>
         <artifactId>lombok</artifactId>
         <optional>true</optional>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>

   <dependencyManagement>
      <dependencies>
         <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
         </dependency>
      </dependencies>
   </dependencyManagement>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
               <excludes>
                  <exclude>
                     <groupId>org.projectlombok</groupId>
                     <artifactId>lombok</artifactId>
                  </exclude>
               </excludes>
            </configuration>
         </plugin>
      </plugins>
   </build>

</project>

Product.java

package com.example.model;

import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

import java.math.BigDecimal;

@AllArgsConstructor
@NoArgsConstructor
@Data
@Builder
@Document(value = "product")
public class Product {
    @Id
    private String id;
    private String name;
    private String description;
    private BigDecimal price;
}

ProductRepository.java

package com.example.repository;

import com.example.model.Product;
import org.springframework.data.mongodb.repository.MongoRepository;

public interface ProductRepository extends MongoRepository<Product, String> {
}

ProductController.java

package com.example.controller;

import com.example.model.Product;
import com.example.repository.ProductRepository;
import lombok.RequiredArgsConstructor;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/api/product")
@RequiredArgsConstructor
public class ProductController {
    private final ProductRepository productRepository;

    @GetMapping

    @ResponseStatus(HttpStatus.OK)
    public List<Product> findAll() {
        return productRepository.findAll();
    }

    @PostMapping
    @ResponseStatus(HttpStatus.CREATED)
    public void createProduct(@RequestBody Product product) {
        productRepository.save(product);
    }
}

ProductServiceApplication.java

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@EnableEurekaClient
public class ProductServiceApplication {

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

}

application.properties

spring.data.mongodb.uri=mongodb://localhost:27017/product-service

spring.application.name=product-service

server.port=0

eureka.instance.instance-id=${spring.application.name}:${random.uuid}

order-service

pom.xml

<?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 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>2.6.7</version>
      <relativePath/> <!-- lookup parent from repository -->
   </parent>
   <groupId>com.example</groupId>
   <artifactId>order-service</artifactId>
   <version>0.0.1-SNAPSHOT</version>
   <name>order-service</name>
   <description>Demo project for Spring Boot</description>

   <properties>
      <java.version>11</java.version>
      <spring-cloud.version>2021.0.2</spring-cloud.version>
   </properties>


   <dependencies>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-data-jpa</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-web</artifactId>
      </dependency>
      <dependency>
         <groupId>org.springframework.cloud</groupId>
         <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
      </dependency>

      <dependency>
         <groupId>mysql</groupId>
         <artifactId>mysql-connector-java</artifactId>
         <scope>runtime</scope>
      </dependency>
      <dependency>
         <groupId>org.projectlombok</groupId>
         <artifactId>lombok</artifactId>
         <optional>true</optional>
      </dependency>
      <dependency>
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-test</artifactId>
         <scope>test</scope>
      </dependency>
   </dependencies>

   <dependencyManagement>
      <dependencies>
         <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-dependencies</artifactId>
            <version>${spring-cloud.version}</version>
            <type>pom</type>
            <scope>import</scope>
         </dependency>
      </dependencies>
   </dependencyManagement>

   <build>
      <plugins>
         <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <configuration>
               <excludes>
                  <exclude>
                     <groupId>org.projectlombok</groupId>
                     <artifactId>lombok</artifactId>
                  </exclude>
               </excludes>
            </configuration>
         </plugin>
      </plugins>
   </build>

</project>

order.java

package com.example.model;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.persistence.*;
import java.util.List;

@Entity
@Table(name = "t_orders")
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
public class Order {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String orderNumber;
    @OneToMany(cascade = CascadeType.ALL)
    private List<OrderLineItems> orderLineItems;
}

OrderLineItems.java

package com.example.model;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;

import javax.persistence.*;
import java.math.BigDecimal;

@AllArgsConstructor
@NoArgsConstructor
@Getter
@Setter
@Entity
@Table(name = "order_line_items")
public class OrderLineItems {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String skuCode;
    private BigDecimal price;
    private Integer quantity;
}

OrderRepository.java

package com.example.repository;

import com.example.model.Order;
import org.springframework.data.jpa.repository.JpaRepository;

public interface OrderRepository extends JpaRepository<Order, Long> {
}

OrderDto.java

package com.example.dto;

import com.example.model.OrderLineItems;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.util.List;

@Data
@AllArgsConstructor
@NoArgsConstructor
@Builder
public class OrderDto {
    private List<OrderLineItems> orderLineItemsList;
}

OrderServiceApplication.java

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@EnableEurekaClient
public class OrderServiceApplication {

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

}

application.properties

#MySQL DB
spring.datasource.url=jdbc:mysql://localhost:3306/order-service
spring.datasource.username=root
spring.datasource.password=password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialect

spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true
spring.datasource.initialization-mode=always

spring.application.name=order-service
server.port=0
eureka.instance.instance-id=${spring.application.name}:${random.uuid}

I will update and modify order-service in next part, here its use just to register into the Discovery-service.