spring cloud eureka服务搭建（生产者消费者）

1. Eureka是什么

Eureka 是 Netflix 开源的服务注册发现组件，服务发现可以说是微服务架构的核心功能了，微服务部署之后，一定要有服务注册和发现的能力，Eureka 就是担任这个角色的。如果你用过 dubbo 的话，那一定知道 dubbo 中服务注册和发现的功能是用 zookeeper 来实现的。

2. Eureka高级架构

如上图所示，其中

Application Server 表示服务提供方

Application Client 表示服务消费方

Make Remote Call 表示远程调用

服务在Eureka上注册，然后每隔30秒发送心跳来更新它们的租约。如果客户端不能多次续订租约，那么它将在大约90秒内从服务器注册表中剔除。注册信息和更新被复制到集群中的所有eureka节点。来自任何区域的客户端都可以查找注册表信息（每30秒发生一次）来定位它们的服务（可能在任何区域）并进行远程调用。
（PS：Eureka Client需要每30秒给Eureka Server发一次心跳，同时更新Server上最新的注册信息到本地，如果Server多次没有收到来自客户端的心跳，那么在90秒内会被Server上剔除）

版本说明

Java : 1.8
Spring Boot : 2.1.5.RELEASE
Spring Cloud: Greenwich.SR1

撸代码

项目结构

父级的pom

<?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.demo</groupId>
    <artifactId>spring-cloud-demo</artifactId>
    <packaging>pom</packaging>
    <version>1.0.0-SNAPSHOT</version>
    <modules>
        <module>eureia/eureka-server</module>
        <module>eureia/eureka-client</module>
        <module>eureia/eureka-consumer</module>
        <module>eureia/eureka-server-peer</module>
        <module>eureia/eureka-server-peer2</module>
    </modules>


    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>

            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-parent</artifactId>
                <version>2.1.5.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.8</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.6.0</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

eureka-server（eureka服务端）

pom.xml文件

<?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>com.demo</groupId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>
    <packaging>jar</packaging>

    <artifactId>eureka-server</artifactId>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <dependency>
            <groupId>javax.xml.bind</groupId>
            <artifactId>jaxb-api</artifactId>
            <version>2.3.1</version>
        </dependency>
        <dependency>
            <groupId>com.sun.xml.bind</groupId>
            <artifactId>jaxb-impl</artifactId>
            <version>2.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jaxb</groupId>
            <artifactId>jaxb-runtime</artifactId>
            <version>2.3.1</version>
        </dependency>
    </dependencies>


</project>

application.properties

spring.application.name=eureka-server

server.port=20000


eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false

# 强制关闭服务自保（自动开关不起作用）
eureka.server.enable-self-preservation=false

# 每隔多久触发一次服务剔除
eureka.server.eviction-interval-timer-in-ms=10000

EurekaServerApplication

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

    public static void main(String[] args) {

        new SpringApplicationBuilder(EurekaServerApplication.class)
                .web(WebApplicationType.SERVLET)
                .run(args);
    }

}

启动EurekaServer

http://localhost:20000/

这样Eureka服务端就启动了简简单单。

eureka-client（eureka生产者）

pom.xml文件

<?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>com.demo</groupId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <packaging>jar</packaging>
    <artifactId>eureka-client</artifactId>
    <name>eureka-client</name>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>


</project>

application.properties

spring.application.name=eureka-client

server.port=30002
# 注册地址（想服务端发送注册指令）
eureka.client.serviceUrl.defaultZone=http://localhost:20000/eureka/


# 每隔5秒钟，向服务中心发送一条续约指令
eureka.instance.lease-renewal-interval-in-seconds=5

# 如果30秒内，依然没有收到续约请求，判定服务过期（上西天）
eureka.instance.lease-expiration-duration-in-seconds=30

EurekaClientApplication

@SpringBootApplication
@EnableDiscoveryClient
public class EurekaClientApplication {

    public static void main(String[] args) {

        new SpringApplicationBuilder(EurekaClientApplication.class)
                .web(WebApplicationType.SERVLET)
                .run(args);
    }

}

Controller

@RestController
@Slf4j
public class Controller {
    Logger log = LoggerFactory.getLogger(Controller.class);
    @Value("${server.port}")
    private String port;

    @GetMapping("/sayHi")
    public String sayHi() {
        return "This is " + port;
    }

    @PostMapping("/sayHi")
    public Friend sayHiPost(@RequestBody Friend friend) {
        log.info("You are " + friend.getName());
        friend.setPort(port);
        return friend;
    }

}

实体类Friend

public class Friend {

    private String name;

    private String port;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPort() {
        return port;
    }

    public void setPort(String port) {
        this.port = port;
    }
}

启动eureka-client（eureka生产者）

这样eureka-client（eureka生产者）就启动成功啦。

eureka-consumer（eureka消费者）

pom.xml文件

<?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>com.demo</groupId>
        <version>1.0.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>eureka-consumer</artifactId>
    <packaging>jar</packaging>
    <name>eureka-consumer</name>

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

    </dependencies>
</project>

application.properties

spring.application.name=eureka-consumer

server.port=31000

eureka.client.serviceUrl.defaultZone=http://localhost:20000/eureka/

EurekaConsumerApplication

@SpringBootApplication
@EnableDiscoveryClient
public class EurekaConsumerApplication {

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

    public static void main(String[] args) {
        new SpringApplicationBuilder(EurekaConsumerApplication.class)
                .web(WebApplicationType.SERVLET)
                .run(args);
    }

}

Controller

@RestController
@Slf4j
public class Controller {

    Logger log = LoggerFactory.getLogger(Controller.class);

    @Autowired
    private LoadBalancerClient client;

    @Autowired
    private RestTemplate restTemplate;

    @GetMapping("/hello")
    public String hello() {
        ServiceInstance instance = client.choose("eureka-client");

        if (instance == null) {
            return "No available instances";
        }

        String target = String.format("http://%s:%s/sayHi",
                instance.getHost(),
                instance.getPort());
        log.info("url is {}", target);

        return restTemplate.getForObject(target, String.class);
    }

    @PostMapping("/hello")
    public Friend helloPost() {
        ServiceInstance instance = client.choose("eureka-client");

        if (instance == null) {
            return null;
        }

        String target = String.format("http://%s:%s/sayHi",
                instance.getHost(),
                instance.getPort());
        log.info("url is {}", target);

        Friend friend = new Friend();
        friend.setName("Eureka Consumer");

        return restTemplate.postForObject(target, friend, Friend.class);
    }

}

实体类Friend

public class Friend {

    private String name;

    private String port;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getPort() {
        return port;
    }

    public void setPort(String port) {
        this.port = port;
    }
}

启动eureka-consumer（eureka消费者）

这里消费者也注册成功了

测试

消费者通过LoadBalancerClient来调用生产者eureka-client提供的接口

通过调用消费者 @PostMapping("/hello")来消费eureka-client提供的sayHi接口。

成功！
如果有问题请指出！！

https://www.cnblogs.com/cjsblog/p/9858154.html
参考文献

本文地址：https://blog.csdn.net/qq_40297844/article/details/109645804