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springcloud之Eureka

回溯 2022-02-14 阅读 81
spring cloudeurekajava

Eureka包含两个组件: Eureka Server和Eureka Client

Eureka Server提供服务注册服务

各个微服务节点通过配置启动后，会在EurekaServer中进行注册，这样EurekaServer中的服务注册表中将会存储所有可用服务节点的信息，服务节点的信息可以在界面中直观看到。

EurekaClient通过注册中心进行访问

是一个Java客户端，用于简化Eureka Server的交互，客户端同时也具备一个内置的、使用轮询(round-robin)负载算法的负载均衡器。在应用启动后，将会向Eureka Server发送心跳(默认周期为30秒)。如果Eureka Server在多个心跳周期内没有接收到某个节点的心跳， EurekaServer将会从服务注册表中把这个服务节点移除（默认90秒)

首先建立一个父工程来管理依赖
pom文件依赖

<?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>com.mql</groupId>
    <artifactId>SpringCloud-2020</artifactId>
    <version>1.0-SNAPSHOT</version>

    <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>

    <!-- 子模块继承之后，提供作用：锁定版本+子modlue不用写groupId和version  -->
    <dependencyManagement>
        <dependencies>
            <!--spring boot 2.2.2-->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.2.2.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
            <!--spring cloud Hoxton.SR1-->
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Hoxton.SR1</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>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <fork>true</fork>
                    <addResources>true</addResources>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

创建服务提供者模块Provider-8001

pom依赖

<?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-2020</artifactId>
        <groupId>com.mql.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Provider-8001</artifactId>
<dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.10</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-jdbc -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-jdbc</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
           <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
 </project>

application.yml

server:
  port: 8001
  
spring:
  application:
    name: cloud-provider-service
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: com.mysql.jdbc.Driver
    url: jdbc:mysql://localhost:3306/db2019?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456
    
mybatis:
  mapperLocations: classpath:mapper/*.xml
  type-aliases-package: com.mql.springcloud.pojo

数据库建表

CREATE TABLE payment (
 id BIGINT(20) NOT NULL AUTO_INCREMENT COMMENT ID,
 'serial' VARCHAR(200) DEFAULT,
 PRIMARY KEY(id)
) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8

创建实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment implements Serializable {
    private Long id;
    private String serial;
}

定义返回结果类，统一封装。

@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);
    }
}

Mapper接口

@Mapper
public interface PaymentMapper {
     int create(Payment payment);
     Payment getPaymentById(@Param("id") Long id);
}

xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.mql.springcloud.mapper.PaymentMapper">
    <insert id="create" parameterType="Payment" useGeneratedKeys="true" keyProperty="id">
            insert into payment(serial) values(${serial});
    </insert>

    <resultMap id="BaseResultMap" type="com.mql.springcloud.pojo.Payment">
        <id column="id" property="id" jdbcType="BIGINT"></id>
        <id column="serial" property="serial" jdbcType="VARCHAR"></id>
    </resultMap>

    <select id="getPaymentById"  parameterType="Long" resultMap="BaseResultMap">
            select * from payment where id=#{id}
    </select>
</mapper>

service接口

public interface PaymentService {

    public int create(Payment payment); //写

    public Payment getPaymentById(@Param("id") Long id);  //读取
}

接口实现类

@Service
public class PaymentServiceImpl implements PaymentService {
    @Resource
    private PaymentMapper paymentMapper;

    public int create(Payment payment){
        return paymentMapper.create(payment);
    }

    public Payment getPaymentById( Long id){

        return paymentMapper.getPaymentById(id);

    }
}

Controller代码

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @PostMapping(value = "/payment/create")
    public CommonResult create(Payment payment){
        int result = paymentService.create(payment);
        log.info("*****插入结果："+result);
        if (result>0){  //成功
            return new CommonResult(200,"插入数据库成功",result);
        }else {
            return new CommonResult(444,"插入数据库失败",null);
        }
    }
    @GetMapping(value = "/payment/get/{id}")
    public CommonResult getPaymentById(@PathVariable("id") Long id){
        Payment payment = paymentService.getPaymentById(id);
        log.info("*****查询结果："+payment);
        if (payment!=null){  //说明有数据，能查询成功
            return new CommonResult(200,"查询成功",payment);
        }else {
            return new CommonResult(444,"没有对应记录，查询ID："+id,null);
        }
    }
}

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测试
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创建消费者模块Provider-80

pom依赖

<?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>SpringCloud-2020</artifactId>
        <groupId>com.mql</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Consumer-80</artifactId>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

    </dependencies>

</project>

application.yml

server:
  port: 80

主启动类

@SpringBootApplication
public class ConsumerMain80 {
    public static void main(String[] args) {
       SpringApplication.run(ConsumerMain80.class,args);
    }
}

远程调用使用RestTemplate模板

@Configuration
public class ApplicationContextConfig {

    @Bean
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }

}

控制器ConsumerController

@RestController
@Slf4j
public class ConsumerController {

    public static final String PAYMENT_URL = "http://localhost:8001";

    @Resource
    private RestTemplate restTemplate;

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

    @GetMapping("/consumer/payment/get/{id}")
    public CommonResult<Payment> getPayment(@PathVariable("id") Long id){
        return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id,CommonResult.class);
    }
}

将Payment和CommonResult复制到这个项目里面。
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测试
在这里插入图片描述
将重复的类抽取出来依赖导入。
新建模块cloud-api-commons
pom依赖

<dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <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>

        <!-- https://mvnrepository.com/artifact/cn.hutool/hutool-all -->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.1.0</version>
        </dependency>
    </dependencies>

将pojo 和result复制到此模块。
执行insatll命令
在其它模块pom文件导入依赖。
在这里插入图片描述

        <dependency>
            <groupId>com.mql</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

这里完成了服务提供者和消费者模块。

Eureka服务注册中心（单机）

新建模块eureka-server-7001
pom依赖

<?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>SpringCloud-2020</artifactId>
        <groupId>com.mql</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>Eureka-server-7001</artifactId>

    <dependencies>
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>com.mql</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>${project.version}</version>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web  -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-test -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
        </dependency>

    </dependencies>

</project>

yml配置文件

server:
  port: 7001

eureka:
  instance:
    hostname: localhost  #eureka服务端的实例名字
  client:
    register-with-eureka: false    #表识不向注册中心注册自己
    fetch-registry: false   #表示自己就是注册中心，职责是维护服务实例，并不需要去检索服务
    service-url:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/    #设置与eureka server交互的地址查询服务和注册服务都需要依赖这个地址

主启动类
注意@EnableEurekaServer注解，开启服务

@EnableEurekaServer
@SpringBootApplication
public class EurekaMain7001 {
    public static void main(String[] args) {
        SpringApplication.run(EurekaMain7001.class,args);
    }
}

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测试
在这里插入图片描述
注册中心好了之后需要将服务注册到注册中心里面。
首先添加客户端依赖。

   <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
   </dependency>

改写yml配置文件

eureka:
  client:
    register-with-eureka: true
    fetchRegistry: true
    service-url:
      defaultZone: http://localhost:7001/eureka

主启动类添加注解@EnableEurekaClient
服务提供者和消费者都是一样的操作。

Eureka服务注册中心（集群）

仿照Eureka7001构造Eureka7002，为了效果更明显，可以做地址映射，修改windows/system32/drivers/etc/host文件
在这里插入图片描述
Eureka7001yml文件

server:
  port: 7001

eureka:
  instance:
    hostname: eureka7001.com  #eureka服务端的实例名字
  client:
    register-with-eureka: false    #表识不向注册中心注册自己
    fetch-registry: false   #表示自己就是注册中心，职责是维护服务实例，并不需要去检索服务
    service-url:
      defaultZone: http://eureka7002.com:7002/eureka/    #设置与eureka server交互的地址查询服务和注册服务都需要依赖这个地址

Eureka7002yml文件

server:
  port: 7002

eureka:
  instance:
    hostname: eureka7002.com   #eureka服务端的实例名字
  client:
    register-with-eureka: false    #表识不向注册中心注册自己
    fetch-registry: false   #表示自己就是注册中心，职责是维护服务实例，并不需要去检索服务
    service-url:
      defaultZone: http://eureka7001.com:7001/eureka/

剩下都是一样的代码。

将Provider8001发布到集群中，修改yml配置文件。

service-url:
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版

将Consumer80发布到集群中，同上面一样修改yml配置文件。
在这里插入图片描述
集群有了，服务也注册了。

搭建提供者集群

仿照Provider8001新建Provider8002
修改yml文件的端口为8002，这里为了体现两个服务提供者的效果，修改两个提供者的Controller。
在这里插入图片描述
在输出信息里添加端口，然后将消费者的调用模式改一下，基于服务名称调用。
在这里插入图片描述

在这里插入图片描述
在RestTemplate对象上添加 @LoadBalanced注解实现负载均衡。

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

把服务都启动。
在这里插入图片描述
在这里插入图片描述
同样的查询服务提供商不一样，说明负载均衡起作用了。

服务发现

注册进eureka里面的微服务，可以通过服务发现来获得该服务的信息
修改Controller，添加方法

 @GetMapping(value = "/payment/discovery")
    public Object discovery(){
        List<String> services = discoveryClient.getServices();
        for (String element : services) {
            log.info("***** element:"+element);
        }
        List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PROVIDER-SERVICE");
        for (ServiceInstance instance : instances) {
            log.info(instance.getServiceId()+"\t"+instance.getHost()+"\t"+instance.getPort()+"\t"+instance.getUri());
        }
        return this.discoveryClient;
    }

主启动类上添加注解@EnableDiscoveryClient
访问http://localhost:8001/payment/discovery就能在控制台看到信息了。
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在这里插入图片描述
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eureka:
  instance:
    instance-id: Provider8001 修改实例名称
    prefer-ip-address: true 访问时ip显示

自我保护机制

服务端禁用

server:
  enable-self-preservation: false

客户端配置

eureka:
  instance:
    lease-expiration-duration-in-seconds: 单位秒
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