Spring Cloud Finchley版本Demo笔记,注册中心、服务注册、服务发现、和注册中心高可用
一、新建Maven,编写父pom.xml
1、打开idea,File->New->Project,新建maven项目:
2、不用选,直接next:
3、指定groupid和artifactid:
4、finish:
5、删除不必要的包,可以把src删掉:
6:、设置父pom.xml,并添加一个子模块eureka:
<?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.cobra</groupId>
<artifactId>springcloud</artifactId>
<version>1.0-SNAPSHOT</version>
<name>SpringCloudDemo</name>
<description>Demo project for Spring Cloud</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.7.RELEASE</version>
<relativePath/>
</parent>
<modules>
<module>eureka</module>
</modules>
<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.RELEASE</spring-cloud.version>
</properties>
<dependencies>
<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>
二、新建子模块,eureka注册中心:
1、new->module:
2、选择Spring Initializr:
3、指定groupid和artifactid,next:
4、选择web、eureka server:
5、next->finish得到:
6、修改修改eureka模块的pom.xml,继承父pom.xml,去掉不必要的依赖:
<?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>
<parent>
<groupId>com.cobra</groupId>
<artifactId>springcloud</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<groupId>com.cobra</groupId>
<artifactId>eureka</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>eureka</name>
<description>Demo project for Spring Boot</description>
<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-server</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
7、修改配置文件后缀名为.yml,配置相关参数:
#端口号
server:
port: 8761
spring:
application:
name: eureka
#hostname
eureka:
instance:
hostname: localhost
client:
#向自己注册,不显示自己等
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://localhost:8761/eureka
8、在启动类上加@EnableEurekaServer,声明自己是一个eureka注册中心:
9:启动eureka模块,并访问http://localhost:8761/
10:如果改配置文件里的register-with-eureka: true,重启则会显示自己:
三、服务注册:
1、新建模块server,选择的依赖为web、eureka discovery:
2、修改子模块的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">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.cobra</groupId>
<artifactId>springcloud</artifactId>
<version>1.0-SNAPSHOT</version>
</parent>
<groupId>com.cobra</groupId>
<artifactId>server</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>server</name>
<description>Demo project for Spring Boot</description>
<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>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
3、并在父pom.xml添加对应module
4、将配置文件改为.yml,配置参数
#端口号
server:
port: 8090
#服务名
spring:
application:
name: server
#向注册中心注册
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka
5、在启动类上加@EnableEurekaClient,声明是个服务端:
6、刷新http://localhost:8761/,发现server注册成功:
四、注册中心高可用
注册中心是微服务中最重要环节,必须保证高可用,防止一台服务挂了,还有可用的注册中心,供服务消费者发现服务提供者:
高可用实现分两步:1)、启用多台注册中心,注册中心之间相互注册;2)、服务向这些启动的服务中心分别注册。
1、假设启用三台注册中心,新建application-server1.yml、application-server2.yml、application-server3.yml,
需要注意的是:
# instance:
# hostname: localhost
需要注释。
2、application.yml配置为:
spring:
profiles:
active: server1
application-server1.yml配置为:
#端口号
server:
port: 8761
spring:
application:
name: eureka
#hostname
eureka:
# instance:
# hostname: localhost
client:
#向自己注册,不显示自己等
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://localhost:8762/eureka/,http://localhost:8763/eureka/
application-server2.yml配置为:
#端口号
server:
port: 8762
spring:
application:
name: eureka2
#hostname
eureka:
# instance:
# hostname: localhost
client:
#向自己注册,不显示自己等
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8763/eureka/
application-server3.yml配置为:
#端口号
server:
port: 8763
spring:
application:
name: eureka3
#hostname
eureka:
# instance:
# hostname: localhost
client:
#向自己注册,不显示自己等
register-with-eureka: false
fetch-registry: false
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka/
3、在父pom.xml添加<packaging>pom</packaging>,到eureka目录下执行mvn clean install将项目打包:
4、server配置不变的情况下(只向8761注册),会发现8762、8763也发现了server:
5、但是这并不够,当8761挂掉,虽然8762、8763还能发现sever,但是当sever重启,8762、8763里面的server依然存在,重启8762、8763就无法发现server了,因此还是有问题。
正确的做法应该是server也同时向多个注册中心注册:
#端口号
server:
port: 8090
#服务名
spring:
application:
name: server
#向注册中心注册
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/,http://localhost:8762/eureka,http://localhost:8763/eureka/