Spring Cloud - Eureka

Eureka服务注册与发现

想巩固一下学习过的Spring Cloud 的各项知识,特此巩固，如果有总结错的地方欢迎指出。

• SpringCloud

  Finchley.RELEASE

• SpringBoot

  2.0.2.RELEASE

Eureka是服务注册与发现，是CS架构模式，分为服务端和客户端两端

<?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.amber</groupId>
    <artifactId>cloud</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>eureka</module>
        <module>mall-consumer</module>
    </modules>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.2.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

ds

    <properties>
        <maven.complier.target>1.8</maven.complier.target>
        <maven.complier.source>1.8</maven.complier.source>
        <java.version>1.8</java.version>
        <spring.boot.version>2.0.2.RELEASE</spring.boot.version>
        <spring.cloud.version>Finchley.RELEASE</spring.cloud.version>
    </properties>

    <repositories>
        <repository>
            <id>spring-snapshots</id>
            <name>Spring Snapshots</name>
            <url>https://repo.spring.io/libs-snapshot</url>
            <snapshots>
                <enabled>true</enabled>
            </snapshots>
        </repository>
    </repositories>

    <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>

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

            <!-- https://mvnrepository.com/artifact/org.springframework/springloaded -->
            <dependency>
                <groupId>org.springframework</groupId>
                <artifactId>springloaded</artifactId>
                <version>1.2.5.RELEASE</version>
            </dependency>

            <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-devtools -->
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
                <version>2.0.5.RELEASE</version>
            </dependency>
        </dependencies>
    </dependencyManagement>


    <build>
        <finalName>${project.version}</finalName>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-resources-plugin</artifactId>
                <configuration>
                    <delimiters>
                        <delimit>$</delimit>
                    </delimiters>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

父工程 pom.xml

Eureka-Server

<!--eureka-server服务端 -->
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

启动类加上@EnableEurekaServer代表这是服务端

package com.amber;

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

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

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

配置文件application.yml

server:
  port: 7001

spring:
  application:
    name: eureka-server

eureka:
  instance:
    hostname: eureka7001.com
  client:
    #eureka不注册自己
    registerWithEureka: false
    #不从eureka中读取数据
    fetchRegistry: false
    serviceUrl:
      #集群
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/

访问: http://eureka7001.com:7001/

http://eureka7002.com:7002/

http://eureka7003.com:7003/

同理，只需要修改

server:
  port: 7002

eureka:
  instance:
    hostname: eureka7002.com

Eureka-Client

<?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>cloud</artifactId>
        <groupId>com.amber</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>mall-consumer</artifactId>

    <dependencies>
        <!--eureka-server服务端 -->
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

    </dependencies>

</project>

pom.xml

  <dependencies>
        <!--eureka-server服务端 -->
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-eureka-server -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-web -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

    </dependencies>

application.yml

server:
  port: 9001

spring:
  application:
    name: consumer-9001

eureka:
  client:
    serviceUrl:
      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/

在配置文件里面也需要添加eureka集群，表示当前服务可以注册要哪些eureka服务中

启动类

package com.amber;

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

@SpringBootApplication
@EnableEurekaClient
public class ConsumerApplication {

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

启动类加上@EnableEurekaClient(只能用于eureka客户端)可以被eureka发现，也可以用@EnableDiscoveryClient(可以被其他服务注册中心发现,包括eureka)。

再次访问http://eureka7001.com:7001/

可以发现consumer-9001以及被注册了

小知识

在使用eureka的时候，会遇到一下的标识。这不是配置出错，是Eureka的自我保护。服务过长时间没有心跳