1. 什么是Spring Cloud? Spring提供了一系列工具,可以帮助开发人员迅速搭建分布式系统中的公共组件(比如:配置管理,服务发现,断路器,智能路由,微代理,控制总线,一次性令牌,全局锁,主节点选举, 分布式session, 集群状态)。协调分布式环境中各个系统,为各类服务提供模板性配置。使用Spring Cloud, 开发人员可以搭建实现了这些样板的应用,并且在任何分布式环境下都能工作得非常好,小到笔记本电脑, 大到数据中心和云平台。 Spring Cloud官网的定义比较抽象,我们可以从简单的东西开始。Spring Cloud是基于Spring Boot的, 最适合用于管理Spring Boot创建的各个微服务应用。要管理分布式环境下的各个Spring Boot微服务,必然存在服务的注册问题。所以我们先从服务的注册谈起。既然是注册,必然有个管理注册中心的服务器,各个在Spring Cloud管理下的Spring Boot应用就是需要注册的client Spring Cloud使用erureka server, 然后所有需要访问配置文件的应用都作为一个erureka client注册上去。eureka是一个高可用的组件,它没有后端缓存,每一个实例注册之后需要向注册中心发送心跳,在默认情况下erureka server也是一个eureka client ,必须要指定一个 server。 2. 创建Eureka Server 1).创建一个Maven工程helloworld.eureka.server, pom.xml内容如下: - <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.cloud</groupId>
- <artifactId>springcloud.helloworld.eureka.server</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <name>springcloud.helloworld.Eureka.server</name>
- <description>Demo Spring Eureka Server</description>
- <parent>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-parent</artifactId>
- <version>1.5.3.RELEASE</version>
- <relativePath /> <!-- lookup parent from repository -->
- </parent>
-
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
- <java.version>1.8</java.version>
- </properties>
-
- <dependencies>
- <!--eureka server -->
- <dependency>
- <groupId>org.springframework.cloud</groupId>
- <artifactId>spring-cloud-starter-eureka</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.cloud</groupId>
- <artifactId>spring-cloud-starter-eureka-server</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.cloud</groupId>
- <artifactId>spring-cloud-starter-config</artifactId>
- </dependency>
- <!-- spring boot test-->
- <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>Dalston.RC1</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>
-
- <repositories>
- <repository>
- <id>spring-milestones</id>
- <name>Spring Milestones</name>
- <url>https://repo.spring.io/milestone</url>
- <snapshots>
- <enabled>false</enabled>
- </snapshots>
- </repository>
- </repositories>
- </project>
复制代码2). 用Spring Boot创建一个服务类EurekaServerApplication,需要一个注解@EnableEurekaServer加在springboot工程的启动类上 - package springcloud.helloworld.eureka.server;
- import org.springframework.boot.SpringApplication;
- import org.springframework.boot.autoconfigure.SpringBootApplication;
- import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
- @EnableEurekaServer
- @SpringBootApplication
- public class EurekaServerApplication {
- public static void main(String[] args) {
- SpringApplication.run(EurekaServerApplication.class, args);
- }
- }
复制代码3).eureka server的配置文件bootstrap.yml,其中registerWithEureka:false和fetchRegistry:false表明自己是一个eureka server server:
port: 8761
eureka:
instance:
hostname: 127.0.0.1
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://127.0.0.1:8761/eureka/ 4) eureka server的工程结构如下 server:
port: 8761
eureka:
instance:
hostname: 127.0.0.1
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://127.0.0.1:8761/eureka/ 5)启动eureka server,然后访问http://localhost:8761, 界面如下, "No instances available" 表示无client注册 3. 创建Eureka Client 1). 创建一个Maven工程helloworld.eureka.client, pom.xml内容如下: - <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.cloud</groupId>
- <artifactId>springcloud.helloworld.eureka.client</artifactId>
- <version>0.0.1-SNAPSHOT</version>
- <name>springcloud.helloworld.eureka.client</name>
- <description>Demo Spring Boot Client</description>
- <parent>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-parent</artifactId>
- <version>1.5.3.RELEASE</version>
- <relativePath /> <!-- lookup parent from repository -->
- </parent>
- <properties>
- <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
- <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
- <java.version>1.8</java.version>
- </properties>
- <dependencies>
- <dependency>
- <groupId>org.springframework.cloud</groupId>
- <artifactId>spring-cloud-starter-eureka</artifactId>
- </dependency>
- <dependency>
- <groupId>org.springframework.boot</groupId>
- <artifactId>spring-boot-starter-web</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>Dalston.RC1</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>
- <repositories>
- <repository>
- <id>spring-milestones</id>
- <name>Spring Milestones</name>
- <url>https://repo.spring.io/milestone</url>
- <snapshots>
- <enabled>false</enabled>
- </snapshots>
- </repository>
- </repositories>
- </project>
复制代码2). 创建主类EurekaClientApplication - package springcloud.helloworld.eureka.client;
- import org.springframework.beans.factory.annotation.Value;
- import org.springframework.boot.SpringApplication;
- import org.springframework.boot.autoconfigure.SpringBootApplication;
- import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
- import org.springframework.web.bind.annotation.RequestMapping;
- import org.springframework.web.bind.annotation.RestController;
- @RestController
- @SpringBootApplication
- @EnableEurekaClient
- public class EurekaClientApplication {
- public static void main(String[] args) {
- SpringApplication.run(EurekaClientApplication.class, args);
- }
- @Value("${server.port}")
- String port;
- @RequestMapping("/")
- public String home() {
- return "hello world from port " + port;
- }
- }
复制代码3) eureka client的配置文件bootstrap.yml eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
server:
port: 8762
spring:
application:
name: service-helloworld 4). Client启动后, 可以访问http://localhost:8762 5). 再次访问服务器端口, 可以看到Service Helloworld已经自动注册到之前的server中
|