Spring Cloud Eureka（服务注册与消费详解）

本文转载自：https://blog.csdn.net/chou342175867/article/details/79632525

先说下几点注意：

1、maven版本要与ideal版本匹配，并且ideal版本在2018.1.3以上，不然启动后总是退出，还不报错

2、maven镜像中，要删除阿里云的国内镜像，配置如下面的镜像，不然spring cloud有些版本get不到

1.Spring Cloud Eureka 服务注册中心 Eureka原理参考原文

2.项目工具及环境

JDK1.8
Spring boot 2.0.0
Intellij Idea 2018.1.4
maven 3.5.3
maven下载资源包的时候会遇到无法下载的问题；更改maven镜像为国外的地址
<mirror> <id>ui</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>http://uk.maven.org/maven2/</url> </mirror> <mirror> <id>sprintio</id> <mirrorOf>central</mirrorOf> <name>Human Readable Name for this Mirror.</name> <url>https://repo.spring.io/libs-snapshot/</url>
3.开始创建项目
- 开始搭建
  1.先打建一个最基础的maven项目，然后就自己next，再依次填写即可
  
  2.删除最该maven项目下的src文件夹，新建moudel
  
  新建spring boot项目
  
  先不选择依赖
- 然后搭建项目基本目录

4.进行配置

1.. 配置项目的公共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>cn.qx</groupId>
    <artifactId>eureka</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>demo-server1</module>
        <module>demo-clent1</module>
    </modules>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </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>Finchley.M8</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-cache</artifactId>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>org.springframework.cloud</groupId>-->
            <!--<artifactId>spring-cloud-config-server</artifactId>-->
        <!--</dependency>-->

        <dependency>
            <groupId>org.springframework.session</groupId>
            <artifactId>spring-session-core</artifactId>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </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>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>


</project>

2.. eureka-server的pom.xml文件的配置

<?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>eureka</artifactId>
        <groupId>cn.qx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>demo-sever1</artifactId>

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

3.. eureka-server的application.yml

server:
  port: 8001
spring:
  application:
    name: demo-server1

eureka:
  instance:
    hostname: localhost
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      #defaultZone: http://peer2:8002/eureka,http://peer3:8003/eureka
      defaultZone: http://localhost:8001/eureka/

4.. eureka-server的启动注解

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class DemoServer1Application {

    public static void main(String[] args) {
        SpringApplication.run(DemoServer1Application.class, args);
    }
}

配置好后启动即可。
eureka-server注册中心启动截图

5.eureka-client客户端，可以业务工程可以理解为服务提供者

eureka-client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>eureka</artifactId>
        <groupId>cn.qx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>demo-client1</artifactId>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!--必须引入-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>
</project>

ureka-client的application.yml

spring:
  application:
    name: demo-clent
server:
  port: 9001

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8001/eureka/

eureka-client启动注解

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@EnableEurekaClient
public class DemoClent1Application {

    public static void main(String[] args) {
        SpringApplication.run(DemoClent1Application.class, args);
    }
}

eureka-client创建一个HelloController提供外界访问

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @RequestMapping("/info")
    public String Hello(){
        return "hello xxx，this is demo-client1 messge";
    }
    /*
        服务提供者
     */
    @RequestMapping("/producerHello")
    public String Hello(@RequestParam("name") String name){
        return "hello " + name + "，this is demo-client1 messge";
    }
}

可以再创建一个服务提供者，仅仅application.yml端口不一样，其它的无区别

spring:
  application:
    name: demo-clent
server:
  port: 9002

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8001/eureka/

eureka-consumer配置及代码

ss

eureka-consumer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>eureka</artifactId>
        <groupId>cn.qx</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>demo-consumer1</artifactId>

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
    <!--与原来的feign依赖包引用不一样-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <!--必须引入-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
</dependencies>
</project>

eureka-consumer的application.yml

spring:
  application:
    name: demo-consumer1

server:
  port: 7001

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8001/eureka/

eureka-consumer的代码

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@EnableEurekaClient
@EnableFeignClients
@SpringBootApplication
public class DemoConsumer1Application {

    public static void main(String[] args) {
        SpringApplication.run(DemoConsumer1Application.class, args);
    }
}
//@EnableDiscoveryClient :启用服务注册与发现
//@EnableFeignClients：启用feign进行远程调用

eureka-consumer的feign调用实现

//name:远程服务名，即spring.application.name配置的名称
@Service
@FeignClient(name= "demo-clent")
public interface HelloRemote {
    //需要匹配服务提供者接口名称
    @RequestMapping(value = "/producerHello")
    public String sayHello(@RequestParam(value="name") String name);
}

eureka-consumer的web层调用实现

@RestController
public class ConsumerController {

    @Autowired
    HelloRemote helloRemote;

    /*
        消费者的接口，去调用服务提供者
        问题：只能使用@RequestMapping("/consumerHello/{name}")  @PathVariable("name")方法 不知道有没有其它方式代替？
     */
    @RequestMapping("/consumerHello/{name}")
    public String index(@PathVariable("name") String name){
        return helloRemote.sayHello(name);
    }
    //有问题的
//    @RequestMapping("/consumerHello2")
//    public String index2(@RequestParam("name") String name){
//        return helloRemote.sayHello(name);
//    }
    @RequestMapping("/info")
    public String info(){
        return " Hi,I am a consumer!";
    }
}

测试
分别启动DemoServer1,DemoClient1,DemoClient2,DemoConsumer工程

在浏览器中输入http://localhost:8001/ 会出现2个 DEMO-CLENT项目，一个DEMO-CONSUMER1
在浏览器中输入http://localhost:9001/info会出现 hello xxx，this is demo-client1 messge
在浏览器中输入http://localhost:9002/info会出现 hello xxx，this is demo-client2 messge
在浏览器中输入http://localhost:7001/consumerHello/name会出现 hello name，this is demo-client1 messge ，多次访问会出现hello name，this is demo-client2 messge；因为服务中心自动提供了服务均衡负载的功能

Eureka-Server集群的配置参考Eureka-Server集群

问题集合

问题： eureka-client注册不上
解决：添加 spring-boot-starter-web依赖包

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

问题：spring-cloud-starter-feign依赖包引入不进来
解决：feign的依赖包名字有点改变，需要引入spring-cloud-starter-openfeign

Spring Cloud Eureka（服务注册与消费详解）

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