SpringCloud之Eureka注册Demo

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早在18年的时候写过一篇关于Eureka的文章，不过在那以后就没有深入学习SpringCloud了，恰好最近比较空闲，适合沉下心来好好学习SpringCloud，所以还是从注册中心开始，写个Demo记录一下。

此篇文章代码参考了哔哩哔哩上黑马程序员的视频，在教学代码上稍作修改了，视频链接：www.bilibili.com/video/BV1LQ…

数据库用的MySQL，用到的2张表

用idea创建maven项目，目录结构如图：

最外层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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
 
    <groupId>org.example</groupId>
    <artifactId>spring-cloud-demo</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>user-service</module>
        <module>order-service</module>
        <module>eureka-server</module>
    </modules>
 
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.10.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>
        <spring-cloud.version>Hoxton.SR10</spring-cloud.version>
        <mysql.version>8.0.23</mysql.version>
        <mybatis-plus.version>3.4.1</mybatis-plus.version>
    </properties>
 
    <dependencyManagement>
        <dependencies>
            <!-- springCloud -->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!-- mysql驱动 -->
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            <!-- mybatis-plus -->
            <dependency>
                <groupId>com.baomidou</groupId>
                <artifactId>mybatis-plus-boot-starter</artifactId>
                <version>${mybatis-plus.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
            </dependency>
        </dependencies>
    </dependencyManagement>
 
</project>

注册中心eureka-server的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>eureka-server</artifactId>
 
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
 
    <dependencies>
        <!--eureka服务端-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
    </dependencies>
 
</project>

注册中心配置文件

server:
  port: 8761
 
spring:
  application:
    name: eureka-server
 
eureka:
  client:
    # eureka的地址信息
    service-url:
      defaultZone: http://127.0.0.1:8761/eureka

注册中心启动类，@EnableEurekaServer开启注册服务：

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
 
/**
 * @author wl
 * @date 2022/3/4 14:53
 */
@EnableEurekaServer
@SpringBootApplication
public class EurekaApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaApplication.class, args);
    }
}

打开浏览器，输入localhost:8761，发现有1个服务注册了，就是注册中心自己

注册中心搭建好后，开始搭建客户端注册更多的服务，本例参照黑马程序员的视频写了一个订单模块和用户模块。

用户模块的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>user-service</artifactId>
 
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- mybatis-plus -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <!--eureka客户端依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>
    <build>
        <finalName>app</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
 
</project>

配置文件

server:
  port: 8001
 
spring:
  application:
    name: user-service
  datasource:
    driverClassName: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/cloud_user?characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: 用户名
    password: 密码
 
eureka:
  client:
    # eureka的地址信息
    service-url:
      defaultZone: http://127.0.0.1:8761/eureka
 
#mybatis日志
mybatis-plu:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

其余代码不放了，放个controller层代码

package com.wl.user.controller;
 
import com.wl.user.entiry.User;
import com.wl.user.service.UserService;
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.RestController;
 
/**
 * @author wl
 * @date 2022/3/4 14:12
 */
@RestController
@RequestMapping("/user")
public class UserController {
 
    private final UserService userService;
 
    @Autowired
    public UserController(UserService userService) {
        this.userService = userService;
    }
 
    @GetMapping("/{id}")
    public User getUserById(@PathVariable("id") Long id) {
        return userService.getById(id);
    }
}

为了方便演示，启动2个用户模块实例

订单模块的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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-demo</artifactId>
        <groupId>org.example</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
 
    <artifactId>order-service</artifactId>
 
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>
        <!-- mybatis-plus -->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>user-service</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>RELEASE</version>
            <scope>compile</scope>
        </dependency>
        <!--eureka客户端依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>
    <build>
        <finalName>app</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
 
</project>

订单模块配置文件

server:
  port: 8080
 
spring:
  application:
    name: order-service
  datasource:
    driverClassName: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://127.0.0.1:3306/cloud_order?characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
    username: 用户名
    password: 密码
 
eureka:
  client:
    # eureka的地址信息
    service-url:
      defaultZone: http://127.0.0.1:8761/eureka
 
#mybatis日志
mybatis-plu:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

因为要演示的功能为根据订单id查询订单信息和用户信息，订单模块只查询订单信息，用户信息则由用户模块查询，所以这里需要订单模块远程调用用户模块的接口，这里用到RestTemplate来实现。

新建一个配置类，将RestTemplate注入到Spring容器当中，其中@LoadBalanced是开启负载均衡的注解

package com.wl.order.config;
 
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
 
/**
 * @author wl
 * @date 2022/3/4 15:10
 */
@Configuration
public class RestTemplateConfig {
 
    @Bean
    @LoadBalanced //开启负载均衡的功能
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

订单模块其余代码不放了，这里只放出service层实现类的代码

package com.wl.order.service.impl;
 
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.wl.order.entity.Order;
import com.wl.order.mapper.OrderMapper;
import com.wl.order.service.OrderService;
import com.wl.user.entiry.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
 
/**
 * @author wl
 * @date 2022/3/4 14:42
 */
@Service
public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements OrderService {
    private final RestTemplate restTemplate;
 
    @Autowired
    public OrderServiceImpl(RestTemplate restTemplate) {
        this.restTemplate = restTemplate;
    }
 
    @Override
    public Order getOrderById(Long id) {
        Order order = baseMapper.selectById(id);
        String url = "http://user-service/user/" + order.getUserId();
        User user = restTemplate.getForObject(url, User.class);
        order.setUser(user);
        return order;
    }
}

启动订单模块和用户模块，查看注册中心

用postman测试

再看idea控制台，可以看到用户模块一个实例接收到了一个请求