JAVA 微服务 Spring Cloud之Eureka(AP)

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原创最新推荐文章于 2026-05-24 15:22:50 发布 427 阅读 AI 写同款· GEO 优化 ›

java 面试备战---分布式那点事分布式一致性：CAP理论集中式应用进行服务化拆分后，必然会出现一个问题：如何保证各个节点（Node）之间的数据一致性？比如以下场景：用户首先发起一次更新操作，映射到节点A；然后，用户又做了一次查询操作，操作映射到了节点B，此时A和B的数据如果不一致，对用户来说就会造成困扰。分布式系统为了提高可用性，必然会引入冗余机制（副本），而冗余便带来了上面描述的一致性问题。为了解决这类问题，加州大学伯克利分校的Eric Brewer) 教授提出了 CAP 猜想。2年后， Seth Gilbert 和 Nancy 阅读详情

Spring Cloud之Eureka

Eureka服务注册中（AP）

Eureka服务注册中（AP）

在这里插入图片描述

Eureka(AP)是基于REST（Representational State Transfer）服务注册中心.
C 一致性(Consistency)
A 可用性(Availability)
P 分区容错性(Tolerance of network Partition)
AP 保证了高可用与分区容错性

采用springboot2.2.5.RELEASE+ springCloud Hoxton.SR3 版本

Eureka 集群模式实战案例

创建Maven父项目

项目名称：cloud

pom

    <!-- 统一管理jar包版本 -->
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <junit.version>4.12</junit.version>
        <log4j.version>1.2.17</log4j.version>
        <lombok.version>1.16.18</lombok.version>
        <mysql.version>5.1.47</mysql.version>
        <druid.version>1.1.16</druid.version>
        <mybatis.spring.boot.version>1.3.0</mybatis.spring.boot.version>
    </properties>

    <dependencyManagement>
        <dependencies>
            <!--spring boot 2.2.5-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.2.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--spring cloud Hoxton.SR3-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--spring cloud alibaba 2.1.0.RELEASE-->
            <dependency>
                <groupId>com.alibaba.cloud</groupId>
                <artifactId>spring-cloud-alibaba-dependencies</artifactId>
                <version>2.1.0.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
                <version>${mysql.version}</version>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
                <version>${druid.version}</version>
            </dependency>
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</artifactId>
                <version>${mybatis.spring.boot.version}</version>
            </dependency>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
                <version>${junit.version}</version>
            </dependency>
            <dependency>
                <groupId>log4j</groupId>
                <artifactId>log4j</artifactId>
                <version>${log4j.version}</version>
            </dependency>
            <dependency>
                <groupId>org.projectlombok</groupId>
                <artifactId>lombok</artifactId>
                <version>${lombok.version}</version>
                <optional>true</optional>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <!--maven插件 用于热部署-->
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                    <addResources>true</addResources>
                </configuration>
            </plugin>
        </plugins>
    </build>

公共类以及实体类模块

result类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class CommonResult<T>{

    private Integer code;
    private String message;
    private T   data;

    public CommonResult(Integer code,String message){
        this(code,message,null);
    }

}

实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment implements Serializable {

    private long id;

    private String serial;
}

pom

   <dependencies>
        <!--热部署-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>
        <!--实体类 工具-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.1.0</version>
        </dependency>
    </dependencies>

生产者模块

生产者1

创建Module模块
名称：cloud-provider-payment8001
pom

<dependencies>
       <dependency>
           <groupId>org.springframework.cloud</groupId>
           <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
       </dependency>
       <dependency><!-- 引入自己定义-->
           <groupId>com.eureka.springcloud</groupId>
           <artifactId>cloud-api-commons</artifactId>
           <version>${project.version}</version>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-web</artifactId>
       </dependency>
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-actuator</artifactId>
       </dependency>
       <dependency>
           <groupId>org.mybatis.spring.boot</groupId>
           <artifactId>mybatis-spring-boot-starter</artifactId>
       </dependency>
       <dependency>
           <groupId>com.alibaba</groupId>
           <artifactId>druid-spring-boot-starter</artifactId>
           <version>1.1.10</version>
       </dependency>
       <!--mysql-connector-java-->
       <dependency>
           <groupId>mysql</groupId>
           <artifactId>mysql-connector-java</artifactId>
       </dependency>
       <!--jdbc-->
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-starter-jdbc</artifactId>
       </dependency>
        <!-- 热部署工具       -->
       <dependency>
           <groupId>org.springframework.boot</groupId>
           <artifactId>spring-boot-devtools</artifactId>
           <scope>runtime</scope>
           <optional>true</optional>
       </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>

server:
 port: 8001
spring:
 application:
   name: cloud-payment-service
 datasource:
   type: com.alibaba.druid.pool.DruidDataSource
   driver-class-name: com.mysql.jdbc.Driver
   url: jdbc:mysql://localhost:3306/xxx?useUnicode=true&characterEncoding=utf-8&useSSL=false
   password: root
   username: root
mybatis:
 mapper-locations: classpath:mapper/*.xml
 type-aliases-package: com.demo.springcloud.entities

eureka:
 client:
   #表示是否将自己注册进EurekaServer默认为true。
   register-with-eureka: true
   #是否从EurekaServer抓取已有的注册信息，默认为true。单节点无所谓，集群必须设置为true才能配合ribbon使用负载均衡
   fetch-registry: true
   # eureke地址
   service-url:
     defaultZone: http://eureka7001:7001/eureka,http://eureka7002.com:7002/eureka
 instance:
   instance-id: patment8001
   prefer-ip-address: true

生产者2 同上端口修改为8002

启动类使用注解

@EnableEurekaClient
@EnableDiscoveryClient

消费者模块

yml

server:
  port: 80

eureka:
  client:
    register-with-eureka: true
    fetch-registry: true
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
spring:
  application:
    name: cloud-order-server

使用 RestTemplate 模板

@Configuration
public class ApplicationContextConfig {

    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

controller

@RestController
public class OrderController {
    //单机
    //private static final String  PAYMENT_URL="http://localhost:8001/";
    private static  final String PAYMENT_URL="http://CLOUD-PAYMENT-SERVICE/";
    @Resource
    private RestTemplate restTemplate;

    @GetMapping("consumer/create")
    public CommonResult<Payment> create(Payment payment){
     return  restTemplate.postForEntity(PAYMENT_URL+"payment/create",payment,CommonResult.class).getBody();
    }

    @GetMapping("consumer/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") long id){
        CommonResult forObject = restTemplate.getForObject(PAYMENT_URL + "payment/get/" + id, CommonResult.class);
        return  forObject;
    }
}

服务注册

需要在 hosts文件添加者=这两句
127.0.0.1 eureka7001.com
127.0.0.1 eureka7002.com
eureka 集群
7001yml

server:
  port: 7001

eureka:
  instance:
    hostname: eureka7001.com
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://eureka7002.com:7002/eureka
  server:
    enable-self-preservation: false
    eviction-interval-timer-in-ms: 2000

7002yml

server:
  port: 7002

eureka:
  instance:
    hostname: eureka7002.com
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka
  server:
    enable-self-preservation: false
    eviction-interval-timer-in-ms: 2000

两个服务的启动类都需要添加注解
@EnableEurekaServer

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