Spring Cloud简介
Spring Cloud是一系列框架的有序集合。它利用Spring Boot的开发便利性巧妙地简化了分布式系统基础设施的开发，如服务发现注册、配置中心、消息总线、负载均衡、断路器、数据监控等，都可以用Spring Boot的开发风格做到一键启动和部署。Spring Cloud并没有重复制造轮子，它只是将目前各家公司开发的比较成熟、经得起实际考验的服务框架组合起来，通过Spring Boot风格进行再封装屏蔽掉了复杂的配置和实现原理，最终给开发者留出了一套简单易懂、易部署和易维护的分布式系统开发工具包。
服务注册中心-Eureka Server
Eureka Service为框架内的服务提供注册功能。微服务在启动后，可以自动注册到Eureka Service提供的服务注册中心里，用户可以通过注册中心检测微服务的健康情况。
idea创建
File->new->project->Spring Initializr
next
next->Cloud Discory->Eureka Server
next->finish
pom
创建后的pom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/4.0.0 http://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>2.1.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</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>
<!--eureka server Spring Cloud 2.0.0以上引入 -->
<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>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
</project>
2.0以下版本需要引入以下依赖
<!--eureka server -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
2.0以上版本需要引入以下依赖
<!--eureka server -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
application.yml
server:
port: 8761
eureka:
instance:
hostname: localhost
client:
#服务器端不注册eureka
registerWithEureka: false
#服务器端不需要抓取服务列表
fetchRegistry: false
serviceUrl:
#注册中心地址
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
server:
enable-self-preservation: false # 设为false，关闭自我保护
eviction-interval-timer-in-ms: 40000 # 清理间隔（单位毫秒，默认是60*1000）
DemoEurekaApplication.java
Eureka Server需要在启动类上添加@EnableEurekaServer注解
@EnableEurekaServer
@SpringBootApplication
public class DemoEurekaApplication {
public static void main(String[] args) {
SpringApplication.run(DemoEurekaApplication.class, args);
}
}
运行效果
启动项目后浏览器访问http://localhost:8761
微服务提供者-Eureka Client
idea创建
项目创建方式同上，在选择组件时选择web->web可以直接引入web依赖
pom
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.1.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.ljq</groupId>
<artifactId>demo_client1</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo_client1</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
<spring-cloud.version>Greenwich.RC2</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!--eureka client Spring Cloud 2.0.0以上引入-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${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>
<snapshots>
<enabled>false</enabled>
</snapshots>
</repository>
</repositories>
</project>
2.0以下版本需要引入以下依赖
<!--eureka client-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
2.0以上版本需要引入以下依赖
<!--eureka client-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>
application.yml
spring:
application:
#微服务名称，名字中不要出现下划线“_”，否则在使用Feign时会报错
name: service-client1
eureka:
client:
serviceUrl:
#注册中心地址
defaultZone: http://localhost:8761/eureka/
server:
#服务开放端口
port: 8762
DemoClient1Application.java
2.0版本以下需要在启动类添加@EnableEurekaClient注解
2.0版本以上则无需添加注解
@SpringBootApplication
@RestController
public class DemoClient1Application {
/**
* 测试接口
* @return
*/
@GetMapping("/test")
public String test(){
return "测试成功！";
}
public static void main(String[] args) {
SpringApplication.run(DemoClient1Application.class, args);
}
}
运行效果
运行项目后查看注册中心。
service-client1服务已经注册到注册中心。
查看客户端接口
浏览器输入http://localhost:8762/test
参数配置
server:
port: 8761
eureka:
instance:
hostname: localhost
#注册中心接受client注册间隔，默认为90s，不可小于leaseRenewalIntervalInSeconds
lease-expiration-duration-in-seconds: 30
#client发给注册中心心跳的频率，默认为30s，若注册服务过慢可修改此值
lease-renewal-interval-in-seconds: 15
# 设置微服务调用地址为IP优先（默认为false）
prefer-ip-address: true
# 只有prefer-ip-address=true时才会生效
ip-address: 192.168.6.66
client:
#服务器端不注册eureka
registerWithEureka: false
#服务器端不需要抓取服务列表
fetchRegistry: false
serviceUrl:
#注册中心地址
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
#表示客户端多久去拉取一次服务注册信息，默认为30秒
registry-fetch-interval-seconds: 30
#开启健康检查（依赖spring-boot-starter-actuator）
healthcheck:
enabled: true
server:
#是否开启自我保护模式，默认为true
enable-self-preservation: false
#清理无效节点的时间间隔，单位毫秒，默认是60*1000
eviction-interval-timer-in-ms: 40000
