SpringCloud 学习笔记 01 --eureka

1. 新建maven父工程

父工程pom依赖

<!-- 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>

    <!-- 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>

2. eureka服务端子模块

a. pom 依赖

<dependencies>
    <!--eureka-server-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    </dependency>
    <!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
    <dependency>
        <groupId>org.mc.mycloud</groupId>
        <artifactId>cloud-api-commons</artifactId>
        <version>${project.version}</version>
    </dependency>
    <!--boot web actuator-->
    <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>
    <!--一般通用配置-->
    <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>
    </dependency>
    <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>

b. application.yml

server:
  port: 7001

eureka:
  instance:
    hostname: eureka7001.com #eruka服务端实例
  client:
    register-with-eureka: false #false代表不让注册中心注册自己
    fetch-registry: false       #false表示自己就是注册中心，职责是维护服务实例，不需要检索服务
    service-url:
      #设置与eureka server 交互的地址查询服务和注册服务依赖地址
      #单机注册自己 集群注册自己以外的所有
      #单机：
      #defaultZone: http://eureka7001.com:7001/eureka/
      #集群
      defaultZone: http://eureka7002.com:7002/eureka/
  server:
    #关闭自我保护机制 保证不可用服务被及时剔除
    enable-self-preservation: false
    #2秒后删除不可以用服务 默认90秒
    eviction-interval-timer-in-ms: 2000

c. 主启动

@SpringBootApplication
@EnableEurekaServer //启用eureka服务器注解
public class EurekaMain7001 {

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

3. 服务提供者子模块

a. pom 依赖

<dependencies>
        <!--包含了sleuth+zipkin-->
   <!--     <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zipkin</artifactId>
        </dependency>-->
        <!--eureka-client-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
            <groupId>org.mc.mycloud</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>
        <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>
        <dependency>
            <groupId>org.mc.mycloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
            <scope>compile</scope>
        </dependency>
    </dependencies>

b. application.yml

server:
  port: 8001  #端口号

spring:
  application:
    name: cloud-payment-service
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource            # 当前数据源操作类型
    driver-class-name: org.gjt.mm.mysql.Driver              # mysql驱动包
    url: jdbc:mysql://localhost:3306/db2019?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: aion
    
mybatis:
  mapperLocations: classpath:mapper/*.xml
  type-aliases-package: org.mc.mycloud.entities    # 所有Entity别名类所在包

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
    fetchRegistry: true
    service-url:
      #单机版
      defaultZone: http://localhost:7001/eureka
#      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
#      集群：高可用，轮询模式
      #主机名称 服务修改
  instance:
    instance-id: payment8001
#    #访问路径可以显示IP地址
    prefer-ip-address: true
#    Eureka客户端向服务端发送心跳的时间间隔，单位为秒(默认是30秒)
    lease-renewal-interval-in-seconds: 1
#    Eureka服务端在收到最后一次心跳后等待时间上限，单位为秒(默认是90秒)，超时将剔除服务
    lease-expiration-duration-in-seconds: 2

c. 主启动

@SpringBootApplication
@EnableEurekaClient  //启动eureka客户端注解
@EnableDiscoveryClient  //启用客户端发现 
public class PaymentMain8001 {
    public static void main(String[] args) {
        SpringApplication.run(PaymentMain8001.class, args);
    }
}

d. 实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment implements Serializable
{
    private Long id;
    private String serial;
}
@Data
@AllArgsConstructor
@NoArgsConstructor 
public class CommonResult<T>  //统一返回结果实体类
{
    private Integer code; 
    private String  message;
    private T       data;

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

e. 流程代码

dao：

@Mapper
public interface PaymentDao
{
    public int creat(Payment payment);

    public Payment getPaymentById(@Param("id") Long id);


}

xml：

<mapper namespace="org.mc.mycloud.dao.PaymentDao">
    <insert id="creat" parameterType="Payment" useGeneratedKeys="true" keyProperty="id">
        insert into payment(serial) values(#{serial})
    </insert>

    <resultMap id="BaseResultMap" type="org.mc.mycloud.entities.Payment">
        <id column="id" property="id" jdbcType="BIGINT"/>
        <id column="serial" property="serial" jdbcType="VARCHAR"/>
    </resultMap>
    <select id="getPaymentById" parameterType="long" resultMap="BaseResultMap">
        select * from payment where id =#{id}
    </select>
</mapper>

service：

public interface PaymentService
{
    public int creat(Payment payment);

    public Payment getPaymentById(@Param("id") Long id);
}
@Service
public class PaymentServiceImpl implements PaymentService {
    @Resource
    private PaymentDao paymentDao;

    @Override
    public int creat(Payment payment) {
        return paymentDao.creat(payment);
    }

    @Override
    public Payment getPaymentById(Long id) {
        return paymentDao.getPaymentById(id);
    }
}

controller:

@RestController
@Slf4j
public class PaymentController {

    @Resource
    private PaymentService paymentService;

    @Value("${server.port}")
    private String serverPort;

 /*   @Resource
    private DiscoveryClient discoveryClient;*/

    @PostMapping(value = "/payment/creat")
    public CommonResult creat(@RequestBody Payment payment) {
        int result = paymentService.creat(payment);
        log.info("*****插入结果：" + result);
        if (result > 0) {
            return new CommonResult(200, "插入数据库成功, serverPort:" + serverPort, result);
        } else {
            return new CommonResult(444, "插入数据库失败, serverPort:" + serverPort, 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) {
            return new CommonResult(200, "查询数据库成功, serverPort:" + serverPort, payment);
        } else {
            return new CommonResult(444, "查询数据库失败, serverPort:" + serverPort + " id：" + id, null);
        }
    }

 /*   @GetMapping("/payment/discovery")
    public Object discovery() {
        //得到服务清单列表
        List<String> services = discoveryClient.getServices();
        for (String service : services) {
            log.info("*****service:"+service);
        }
        //根据服务名称获得服务信息实例
        List<ServiceInstance> instances = discoveryClient.getInstances("CLOUD-PAYMENT-SERVICE");
        for (ServiceInstance instance : instances) {
            log.info(instance.getServiceId()+"\t"+instance.getHost()+"\t"+instance.getPort()+"\t"+instance.getUri());
        }
        return this.discoveryClient;
    }*/
}

f. 结果

{
  "code": 200,
  "message": "查询数据库成功, serverPort:8001",
  "data": {
    "id": 1,
    "serial": "payment支付8001"
  }
}

4. 消费者子模块

a. pom依赖

<dependencies>
<!--        &lt;!&ndash;包含了sleuth+zipkin&ndash;&gt;
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zipkin</artifactId>
        </dependency>-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency><!-- 引入自己定义的api通用包，可以使用Payment支付Entity -->
            <groupId>org.mc.mycloud</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.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>

b. appliaction.yml

server:
  port: 80

spring:
  application:
    name: cloud-consumer-order

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
    fetchRegistry: true
    service-url:
      #单机版
#      defaultZone: http://localhost:7001/eureka
      # 集群版
      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
      #主机名称 服务修改
  instance:
    instance-id: order80
    #访问路径可以显示IP地址
    prefer-ip-address: true
#    #Eureka客户端向服务端发送心跳的时间间隔，单位为秒(默认是30秒)
#    #lease-renewal-interval-in-seconds: 1
#    #Eureka服务端在收到最后一次心跳后等待时间上限，单位为秒(默认是90秒)，超时将剔除服务
#    #lease-expiration-duration-in-seconds: 2

c. 主启动

@SpringBootApplication
@EnableEurekaClient //作为eureka 客户端
public class OrderMain80 {

    public static void main(String[] args) {
        SpringApplication.run(OrderMain80.class, args);
    }
}

d. 开启负载均衡

@Configuration
public class ApplicationContextConfig {
    @Bean
    @LoadBalanced //开启负载均衡
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }
}

e. 流程代码

@RestController
@Slf4j
public class OrderController {
//    public static final String PAYMENT_URL = "http://localhost:8001";
    //使用服务提供实例名称来实现集群时对服务提供者的选择
    public static final String PAYMENT_URL = "http://CLOUD-PAYMENT-SERVICE";

    @Resource
    private RestTemplate restTemplate;

    @PostMapping("/consumer/payment/creat")
    public CommonResult<Payment> creat(Payment payment) {
        log.info("****消费者数据库插入：80");
        return restTemplate.postForObject(PAYMENT_URL + "/payment/creat", payment, CommonResult.class);
    }

    @GetMapping("/consumer/payment/get/{id}")
    public CommonResult<Payment> getPaymentById(@PathVariable("id") Long id) {
        log.info("****消费者数据库查询：80 哈哈哈 id："+id);
        return restTemplate.getForObject(PAYMENT_URL + "/payment/get/" + id, CommonResult.class);
    }


/**/
}

f. 结果

{
  "code": 200,
  "message": "查询数据库成功, serverPort:8001",
  "data": {
    "id": 1,
    "serial": "payment支付8001"
  }
}

5. 总结

a. 客户端集群访问机制？

轮循

b. 为何集群？

高可用 避免宕机造成服务不可用 提高容错

c. 服务端和客服端注解：

@EnableEurekaServer //服务端
@EnableEurekaClient //客户端

d. 开启负载均衡：

@LoadBalanced注解

@LoadBalanced //开启负载均衡
public RestTemplate getRestTemplate() {
    return new RestTemplate();
}

e. 集群时消费者端配置地址为：

服务提供者实例名称

public static final String PAYMENT_URL = "http://CLOUD-PAYMENT-SERVICE";

f. eureka服务端yml

eureka:
  instance:
    hostname: eureka7001.com #eruka服务端实例
  client:
    register-with-eureka: false #false代表不让注册中心注册自己
    fetch-registry: false       #false表示自己就是注册中心，职责是维护服务实例，不需要检索服务
    service-url:
      #设置与eureka server 交互的地址查询服务和注册服务依赖地址
      #单机注册自己 集群注册自己以外的所有
      #单机：
      #defaultZone: http://eureka7001.com:7001/eureka/
      #集群
      defaultZone: http://eureka7002.com:7002/eureka/
  server:
    #关闭自我保护机制 保证不可用服务被及时剔除
    enable-self-preservation: false
    #2秒后删除不可以用服务 默认90秒
    eviction-interval-timer-in-ms: 2000

g. eureka客户端yml

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
    fetchRegistry: true
    service-url:
      #单机版
      defaultZone: http://localhost:7001/eureka
#      defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka
      #主机名称 服务修改
  instance:
    instance-id: payment8001
#    #访问路径可以显示IP地址
    prefer-ip-address: true
#    Eureka客户端向服务端发送心跳的时间间隔，单位为秒(默认是30秒)
    lease-renewal-interval-in-seconds: 1
#    Eureka服务端在收到最后一次心跳后等待时间上限，单位为秒(默认是90秒)，超时将剔除服务
    lease-expiration-duration-in-seconds: 2

h. 服务端自我保护机制关闭

enable-self-preservation: false

i. 服务发现注解

主启动添加

@EnableDiscoveryClient //服务发现注解

j: 服务端集群方式：

互相注册

#单机注册自己：
#defaultZone: http://eureka7001.com:7001/eureka/
#集群注册其他
defaultZone: http://eureka7002.com:7002/eureka/
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