本文中有三個角色掷豺，分別是服務的提供者当船，服務的消費者默辨，注冊中心Eureka
整體流程：
（1）先啟動注冊中心Eureka
（2）啟動服務的提供者缩幸，將服務注冊到注冊中心Eureka上對外提供服務
（3）啟動服務的消費者，在注冊中心中找到服務并完成消費

1盖喷、服務提供者

（1）pom.xm

<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springcloud</groupId>
    <artifactId>producer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>producer</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <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-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>

</project>

（2）配置文件application.yml

server:
  port: 8090
spring:
  application:
    name: spring-cloud-producer
eureka:
  server:
    enable-self-preservation: false #關閉eureka的自我保護暮刃，防止已被關停的節(jié)點也錯誤的顯示在線
  client:
    register-with-eureka: true #否允許客戶端向Eureka 注冊表獲取信息椭懊，服務器為設置為false,客戶端設置為true
    fetch-registry: true #是否允許向Eureka Server注冊信息 如果是服務器端氧猬，應該設置為false
    service-url:
      defaultZone: http://peer1:8761/eureka/ #此eureka server的應用注冊地址

（3）啟動類ProducerApplication.java

@SpringBootApplication
@EnableEurekaClient //如果是其他注冊中心可以使用注解@EnableDiscoveryClient來進行服務的注冊
public class ProducerApplication {

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

}

（4）Controller

@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String hello(@RequestParam String name) {
        return "hello "+name+"，producer is ready";
    }
}

2、服務消費者

（1）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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.6.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springcloud</groupId>
    <artifactId>consumers</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>consumers</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Greenwich.SR1</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </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>

</project>

（2）application.yml

server:
  port: 8091
spring:
  application:
    name: spring-cloud-consumers
eureka:
  server:
    enable-self-preservation: false #關閉eureka的自我保護奕纫，防止已被關停的節(jié)點也錯誤的顯示在線
  client:
    register-with-eureka: true #否允許客戶端向Eureka 注冊表獲取信息匹层，服務器為設置為false,客戶端設置為true
    fetch-registry: true #是否允許向Eureka Server注冊信息 如果是服務器端升筏，應該設置為false
    service-url:
      defaultZone: http://peer1:8761/eureka/ #此eureka server的應用注冊地址

（3）啟動類ConsumersApplication.java

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients //這個注解是通知SpringBoot在啟動的時候您访，掃描被 @FeignClient 修飾的類
public class ConsumersApplication {

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

}

（4）Feign遠程調用灵汪，創(chuàng)建一個remote接口

@FeignClient(name= "spring-cloud-producer")
public interface HelloRemote {
    @RequestMapping(value = "/hello")
    String hello(@RequestParam(value = "name") String name);
}

（5）Controller

@RestController
public class HelloController {

    @Autowired
    private HelloRemote helloRemote;

    @RequestMapping("/hello")
    public String hello(@RequestParam("name") String name) {
        return helloRemote.hello(name);
    }
}

依次啟動eureka峻凫，producer，consumer三個項目譬胎，
在瀏覽器輸入http://localhost:8090/hello?name=springcloud银择，可以看到producer啟動正常浩考。
在瀏覽器輸入http://localhost:8091/hello?name=spring析孽，可以看到客戶端成功通過feign調用了遠程服務hello袜瞬。

負載均衡

復制一份producer邓尤，修改名稱為producer2汞扎，同時修改相應pom文件擅这，修改application.yml中端口號為8092仲翎，修改Controller如下：

@RestController
public class HelloController {
    @RequestMapping("/hello")
    public String hello(@RequestParam String name) {
        return "hello "+name+"溯香，producer2 is ready";
    }
}

啟動producer2玫坛，可以看到應用名為spring-cloud-producer的有兩臺機器。
我們再去訪問消費端的http://localhost:8091/hello?name=spring杜窄，可以看到producer和producer2輪流打印塞耕，說明注冊中心提供了服務負載均衡功能扫外。