2018-08-10 Eureka + MySQL to provide service

Step 1 Build the base Eureka-client project

1. Build a project that acts as a Eureka-client

  4.0.0
  com.example
  eureka-provider
  0.0.1-SNAPSHOT
  
    
        org.springframework.boot
        spring-boot-starter-parent
        2.0.3.RELEASE
         
    
    
    
        UTF-8
        1.8
    
    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    
    
    
        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
    
    
        
            
                org.springframework.cloud
                spring-cloud-dependencies
                Finchley.RELEASE
                pom
                import
            
        
    

2. Create the main-entry for the app

Content of src\main\java\app\EurekaClientApp.java

package app;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

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

3. Prepare application.yml to configure the client

Content of application.yml

spring:
  application:
    name: eureka-client
    
server:
  port: 8766

eureka:
  client:
    register-with-eureka: true
    serviceUrl:
      defaultZone: http://aaa.bbb.ccc.ddd:8761/eureka/
  instance:
    ip-address: 127.0.0.1
    prefer-ip-address: true

Step 2 Add dependency to access MySQL through JPA

1. Add the dependency in the pom.xml

        
        
            org.springframework.boot
            spring-boot-starter-data-jpa
        
        
        
            mysql
            mysql-connector-java
        

2. Update the application.yml file, to define the parameters to MySQL

Content of application.yml

spring:
  application:
    name: eureka-client
  jpa:
    database: MYSQL
    show-sql: true
    hibernate:
      ddl-auto: none
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/xiaoyouhui
    username: root
    password: password123
    driver-class-name: com.mysql.jdbc.Driver

server:
  port: 8766

eureka:
  client:
    register-with-eureka: true
    serviceUrl:
      defaultZone: http://aaa.bbb.ccc.ddd:8761/eureka/
  instance:
    ip-address: 127.0.0.1
    prefer-ip-address: true

3. Create the model-class

package app.domain;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;

@Entity
@Table(name = "member")
public class Member{
  //fields
  //getters & setters
}

4. Create the repository

package app.repository;

import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;

import domain.Member;

@Repository
public interface MemberRepository extends JpaRepository{

}

Step 3 Add a controller to handle request

The controller-class should under the package of the main-entry. Since Spring-boot will scan from the root-package.

Content of src\main\java\app\controller\MainController.java

package app.controller;

import java.util.List;
import java.util.Optional;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import domain.Member;
import repository.MemberRepository;

@RestController
public class MainController {
    @Autowired
    private MemberRepository memberRepository;
    

    @RequestMapping("/greeting")
    public Optional greeting(@RequestParam(value="id", defaultValue="na") String id) {
        return memberRepository.findById(id);
    }

    @RequestMapping("/greetings")
    public List greetings() {
        List list = memberRepository.findAll();
        System.out.println(list.size());
        return list;
    }

    
    @GetMapping(path="/user/{id}")
    public String findById(@PathVariable Long id) {
        return "hello";
    }

    @RequestMapping("/test")
    public @ResponseBody String testm() {
        return "test";
    }
}

Step 4 Configure to open some Actuator end-point

management:
  endpoints:
    web:
      exposure:
        include: "*"
  endpoint:
    shutdown:
      enabled: false

References

• Spring document to access MySQL
• Spring document to build a restful service
• Blog post to configure Actuator