spring cloud Eureka 注册中心

Spring Cloud是一组框架和工具集，用于快速构建分布式系统，为微服务架构提供了全套技术支持。其中，注册中心是Spring Cloud微服务架构中的一个重要组件，它提供了服务注册和发现的功能，是构建分布式系统的基础。本文将介绍Spring Cloud中的Eureka注册中心，并给出相应的示例说明。

Eureka注册中心的原理
Eureka是Netflix开源的分布式服务发现框架，用于实现云端和本地服务的注册和发现。服务提供者将自己的服务信息注册到Eureka Server，服务消费者从Eureka Server获取可用的服务列表，然后通过负载均衡算法选择一个可以提供服务的实例进行调用。Eureka Server可以通过多个节点组成集群，实现高可用和负载均衡的功能。

首先是注册中心服务的创建 选中spring cloud的Eureka service 

新建成功，pom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 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>2.2.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.springboot.e.eurekaserver</groupId>
    <artifactId>eurekaserver</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eurekaserver</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>8</java.version>
        <spring-cloud.version>Hoxton.SR8</spring-cloud.version>
    </properties>
    <dependencies>
        <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>
        </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>
在服务提供者的配置文件application.properties中，配置Eureka注册中心的地址和服务名称。

server.port=8300

spring.application.name=springcloud-eureka-server-8300

eureka.instance.hostname=localhost
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false
eureka.client.service-url.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

# 默认值是true
eureka.server.enable-self-preservation=true
# default is 30
eureka.instance.leaseRenewalIntervalInSeconds=30
# default is 0.85 we can set the value to 0.49
eureka.server.renewalPercentThreshold=0.49
启动类上的注解

 

新建client 服务 注册到注册中心服务8300的服务上

新建成功pom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 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>2.2.5.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>eurekacllient</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eurekacllient</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>8</java.version>
        <spring-cloud.version>Hoxton.SR8</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>

 配置注册信息在配置文件application.properties中

server.port=8085
spring.application.name=eureka-consumer
eureka.client.service-url.defaultZone=http://localhost:8300/eureka/
eureka.healthcheck.enabled=true
eureka.instance.instance-id=${spring.application.name}
eureka.instance.prefer-ip-address=true
eureka.instance.ip-address=127.0.0.1
简单的服务实例

启动类上的注解

启动eureka  service 和 eureka client 

查看注册中心注册信息