SpringBoot eureka

Eureka 基础

Eureka第一次的接触

Posted by Twany on July 20, 2019

上图为eureka架构，以滴滴打车平台为例

eureka注册中心——滴滴平台

编写pom.xml

引入启动器

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      <properties>
      <java.version>1.8</java.version>
      <spring-cloud.version>Greenwich.SR2</spring-cloud.version>
  </properties>
  • 统一管理依赖的版本号 
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      <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>

    编写application.xml

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    server:
port: 10086
spring:
application:
  name: itcast-eureka # 将来作为微服务名称注入到eureka容器
eureka:
client:
  service-url:
    defaultZone: http://localhost:${server.port}/eureka

引导类@EnableEurekaServer

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@SpringBootApplication
@EnableEurekaServer //启用eureka服务端组件
public class ItcastEurekaApplication {
	public static void main(String[] args) {
		SpringApplication.run(ItcastEurekaApplication.class, args);
	}

}

客户端——用户端（服务消费者）

编写pom.xml

  • 和上述注册中心一样，但还要添加 ( 类比安装滴滴APP ) 
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      <!--注册到eureka容器-->
  <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
  </dependency>

    编写application.yml

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    server:
  port: 8081
spring:
  datasource:
      url: jdbc:mysql://127.0.0.1:3306/mybatis? //注意次数，不添加乱码serverTimezone=UTC
      username: root
      password: root
      driver-class-name: com.mysql.cj.jdbc.Driver
  application:
      name: service-provider # 将来会作为微服务的名称
  mybatis:
  type-aliases-package: com.itcast.service.pojo
  eureka:
  client:
      service-url:
      defaultZone: http://localhost:10086/eureka

启动类 @EnableDiscoveryClient

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package com.itcast.service;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import tk.mybatis.spring.annotation.MapperScan;

@MapperScan( basePackages = "com.itcast.service.mapper")
@SpringBootApplication
@EnableDiscoveryClient
public class ItcastServiceProviderApplication {

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

}

客户端——司机端（服务提供者）

pom.xml application.xml 启动类 和上述消费者相同

controller 类

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package com.itcast.service.controller;

import com.itcast.service.pojo.User;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient; //一定不要导错包
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;

import java.util.List;

@Controller
@RequestMapping("consumer/user")
public class UserController {

    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private  DiscoveryClient discoveryClient;// 包含了拉取的所有服务信息

    @GetMapping
    @ResponseBody
    public User queryUserById(@RequestParam("id")int id){
        //得到服务实例
        List<ServiceInstance> instances = discoveryClient.getInstances("service-provider");
        ServiceInstance instanceInfo = instances.get(0);

        return this.restTemplate.getForObject("http://" + instanceInfo.getHost() + ":" + instanceInfo.getPort() + "/user/" + id, User.class);
    }
}

上述代码为得到服务的主机和端口并使用，最开始我使用DiscoveryClient一直显示没有这个Bean，后来才发现是包导错了。

netfix有一个类和这个类相同，我们需要的是import org.springframework.cloud.client.discovery.DiscoveryClient; 切记！

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