Spring Cloud项目搭建

叫我小锅锅 2024-08-19 08:09:00 阅读 50

一、Spring Cloud 简介

Spring cloud 为开发人员提供了快速构建分布式系统的一些工具,包括配置管理、服务发现、断路器、路由、微代理、事件总线、全局锁、决策竞选、分布式会话等。

它运行环境简单,可以在开发人员电脑上运行。另外说明Spring cloud是基于springboot的。

二、创建服务注册中心

在这里我们需要用到的组件Spring cloud Netflix 的Eureka,eureka是一个服务注册和发现模块。

2.1、首先创建一个springboot的maven主工程

在pom文件中引入依赖,spring boot版本为 2.1.1.RELEASE ,spring cloud 版本为 Finchley.RELEASE ,该pom文件作为父pom文件,起到版本依赖控制的作用,其他module工程依赖该pom。具体pom.xml 文件如下:

<?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/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<groupId>com.lbh</groupId>

<artifactId>eurekademo</artifactId>

<version>0.0.1-SNAPSHOT</version>

<packaging>pom</packaging>

<name>EurekaDemo</name>

<description>Demo project for Spring Boot</description>

<parent>

<groupId>org.springframework.boot</groupId>

<artifactId>spring-boot-starter-parent</artifactId>

<version>2.1.1.RELEASE</version>

<relativePath/> <!-- lookup parent from repository -->

</parent>

<modules>

<module>eureka-server</module>

<module>eureka-client</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-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>${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>

2.2 创建两个module工程:eureka-server 作为服务注册中心, eureka-client 作为客户端

右键工程–new–Module – 选择 Spring initialir,与创建boot工程类似。

选择cloud discovery->eureka server。pom.xml 文件如下:

<?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/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<parent>

<groupId>com.lbh</groupId>

<artifactId>eurekademo</artifactId>

<version>0.0.1-SNAPSHOT</version>

<relativePath/> <!-- lookup parent from repository -->

</parent>

<groupId>com.lbh</groupId>

<artifactId>eureka-server</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>eureka-server</name>

<description>Demo project for Spring Boot</description>

<properties>

<java.version>1.8</java.version>

<spring-cloud.version>Greenwich.RC2</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>

<repositories>

<repository>

<id>spring-milestones</id>

<name>Spring Milestones</name>

<url>https://repo.spring.io/milestone</url>

</repository>

</repositories>

</project>

2.3 启动一个服务注册中心 只需要一个注解@EnableEurekaServer,这个注解需要在springboot工程的启动application类上加:

@EnableEurekaServer

@SpringBootApplication

public class EurekaServerApplication {

public static void main(String[] args) {

SpringApplication.run(EurekaServerApplication.class, args);

System.out.println("=======================eureka-server 启动成功=======================");

}

}

2.4、 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(因此可以在内存中完成),在默认情况下erureka server也是一个eureka client ,必须要指定一个 server。eureka server的配置文件appication.yml:

server:

port: 8761

eureka:

instance:

hostname: localhost

client:

registerWithEureka: false

fetchRegistry: false

serviceUrl:

defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

spring:

application:

name: eureka-server

通过eureka.client.registerWithEureka:false和fetchRegistry:false来表明自己是一个eureka server.

2.5、 eureka server 是有界面的,启动工程,打开浏览器访问: http://localhost:8761

三、创建一个服务提供者 (eureka-client)

当client向server注册时,它会提供一些元数据,例如主机和端口,URL,主页等。Eureka server 从每个client实例接收心跳消息。 如果心跳超时,则通常将该实例从注册server中删除。

创建过程同server类似,创建完pom.xml如下:

<?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/4.0.0http://maven.apache.org/xsd/maven-4.0.0.xsd">

<modelVersion>4.0.0</modelVersion>

<parent>

<groupId>com.lbh</groupId>

<artifactId>eurekademo</artifactId>

<version>0.0.1-SNAPSHOT</version>

<relativePath/> <!-- lookup parent from repository -->

</parent>

<groupId>com.lbh</groupId>

<artifactId>eureka-client</artifactId>

<version>0.0.1-SNAPSHOT</version>

<name>eureka-client</name>

<description>Demo project for Spring Boot</description>

<properties>

<java.version>1.8</java.version>

<spring-cloud.version>Greenwich.RC2</spring-cloud.version>

</properties>

<dependencies>

<dependency>

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>

<version>2.0.0.RELEASE</version>

</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>

<repositories>

<repository>

<id>spring-milestones</id>

<name>Spring Milestones</name>

<url>https://repo.spring.io/milestone</url>

</repository>

</repositories>

</project>

通过注解@EnableEurekaClient 表明自己是一个eurekaclient.

@RestController

@EnableEurekaClient

@SpringBootApplication

public class EurekaClientApplication {

public static void main(String[] args) {

SpringApplication.run(EurekaClientApplication.class, args);

System.out.println("====================eureka-client 启动成功=======================");

}

@Value("${server.port}")

String port;

@RequestMapping("/hi")

public String home(@RequestParam(value = "name", defaultValue = "lbh") String name) {

return "hi " + name + " ,i am from port:" + port;

}

}

仅仅@EnableEurekaClient是不够的,还需要在配置文件中注明自己的服务注册中心的地址,application.yml配置文件如下:

server:

port: 8762

spring:

application:

name: eureka-client

eureka:

client:

serviceUrl:

defaultZone: http://localhost:8761/eureka/

需要指明 spring.application.name,这个很重要,这在以后的服务与服务之间相互调用一般都是根据这个name 。 启动工程,打开http://localhost:8761 ,即eureka server 的网址:

你会发现一个服务已经注册在服务中了,服务名为SERVICE-HI ,端口为7862这时打开 http://localhost:8762/hi?name=lbh, 你会在浏览器上看到 :



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