搭建springcloud微服务（二）创建一个简单的微服务工程

搭建springcloud微服务（二）创建springboot项目springcloud-account，方式同eureka，并且注册到eureka上

搭建springcloud微服务（一）创建注册中心eureka服务端：https://blog.csdn.net/x18094/article/details/114757162

启动类

@SpringBootApplication
@EnableEurekaClient
public class SpringcloudAccountApplication {

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

application.yaml

eureka:
  client:
    serviceUrl:
#      eureka的注册中心地址
      defaultZone: http://localhost:8888/eureka/
server:
#  此项目端口号
  port: 8889
spring:
  application:
#    注册进eureka的名字
    name: account-server

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>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.org</groupId>
    <artifactId>springcloud-account</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springcloud-account</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR6</spring-cloud.version>
    </properties>

    <dependencies>
       <!--这里可以换成client，我这里直接就server了-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <!--<dependency>-->
            <!--<groupId>org.springframework.cloud</groupId>-->
            <!--<artifactId>spring-cloud-config-server</artifactId>-->
        <!--</dependency>-->
        <!--配置中心客户端依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-config</artifactId>
        </dependency>
       <!-- 消息总线  https://liuyanzhao.com/9653.html-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-bus-amqp</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zipkin</artifactId>
        </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>

访问：http://localhost:8888/  发现已经注册到eureka上。

eureka警告：这是由于eureka进入自动保护状态。参考：https://www.cnblogs.com/breath-taking/articles/7940364.html

EMERGENCY! EUREKA MAY BE INCORRECTLY CLAIMING INSTANCES ARE UP WHEN THEY'RE NOT. RENEWALS ARE LESSER THAN THRESHOLD AND HENCE THE INSTANCES ARE NOT BEING EXPIRED JUST TO BE SAFE.

在此状态下，server不会删除注册信息，这就有可能导致在调用微服务时，实际上服务并不存在。 
这种保护状态实际上是考虑了client和server之间的心跳是因为网络问题，而非服务本身问题，不能简单的删除注册信息

stackoverflow上，有人给出的建议是： 
1、在生产上可以开自注册，部署两个server 
2、在本机器上测试的时候，可以把比值调低，比如0.49 
3、或者简单粗暴把自我保护模式关闭

eureka.server.enableSelfPreservation=false

创建一个controller

@RestController
public class MyController {
    @GetMapping("hello")
    public String hello() {
        return "hello";
    }
}

访问： http://localhost:8889/hello

hello

一个简单的微服务就创建完毕了！