《Spring Cloud微服务实战》——服务治理 Spring Cloud Eureka

版权声明：本文为博主anzy原创文章，转载请注明地址 https://blog.csdn.net/qq_24549805/article/details/80386403

一、简介

    Spring cloud Eureka是spring Cloud Netflix微服务套件中的一部分，它基于Netflix Eureka做了二次封装，主要负责完成微服务架构中的服务治理功能。Spring  Cloud通过为Eureka增加了Spring Boot 风格的自动化配置，我们只需要通过简单的引入依赖和注解配置就能让Spring Boot构建的微服务应用轻松地与Eureka服务治理体系进行整合。

二、搭建服务注册中心：

    1、首先创建一个基础的Spring boot工程，命名为 eureka-server，并在pom中引入必要内容：

<?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.anzy</groupId>
	<artifactId>eureka-server</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

	<name>eureka-server</name>
	<description>Demo project for Spring Boot</description>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.0.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>
		<!--增加eureka-server的依赖-->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka-server</artifactId>
		</dependency>
		<!--用于测试的，本例可省略-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<!--依赖管理，用于管理spring-cloud的依赖，其中Camden.SR3是版本号-->
	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Camden.SR3</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、通过 @EnableEurekaServer 注解启动一个服务注册中心供给其他应用进行对话。

package com.anzy.eurekaserver;

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

@EnableEurekaServer
@SpringBootApplication
public class EurekaServerApplication {

	public static void main(String[] args) {
//		SpringApplication.run(EurekaServerApplication.class, args);
		new SpringApplicationBuilder(EurekaServerApplication.class).web(true).run(args);
	}
}

3、在默认配置下，该服务注册中心会将自己作为客户端来尝试注册他自己，所以我们需要在application.properties中增加相关配置：

server.port=1111


eureka.instance.hostname=localhost
# 由于应用为注册中心，所以设置为false，代表不想注册中心注册自己
eureka.client.register-with-eureka=false
#由于注册中心的职责就是维护服务实例，他不需要去检索服务，所以设置为false
eureka.client.fetch-registry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

4、完成上述操作启动项目访问 http://localhost:1111,可看到如下信息

可看到Instances currently registered with Eureka

栏下没有注册任何服务。

注：如果启动报错可能原因是引入的jar版本有冲突，可修改一下版本号。

三、注册服务提供者

1、创建一个基础的Spring boot项目，创建项目名为demo，修改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>

	<groupId>com.anzy</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>jar</packaging>

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

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.4.0.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.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>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-actuator</artifactId>
		</dependency>
		<!--增加eureka-server的依赖-->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-eureka</artifactId>
		</dependency>
	</dependencies>

	<!--依赖管理，用于管理spring-cloud的依赖，其中Camden.SR3是版本号-->
	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>Camden.SR3</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、创建controller，添加DiscoverClient

package com.anzy.demo.test;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;


/**
 * Created by anzy on 2018/4/21.
 */
@RestController
public class HelloController {
    private final Logger logger = LoggerFactory.getLogger(HelloController.class);
    @Autowired
    private DiscoveryClient discoveryClient;

    @GetMapping("hello")
    public String hello(){
        ServiceInstance instance = discoveryClient.getLocalServiceInstance();
        logger.info("/hello,host:" + instance.getHost() + ",service_id:"+instance.getServiceId());
        return "hello spring boot";
    }

}

3、在主类（启动类）里面添加@EnableEurekaClient

package com.anzy.demo;

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

@EnableEurekaClient
@SpringBootApplication
public class DemoApplication {

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

4、修改配置文件application.properties

spring.application.name=demo

eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka

5、启动项目，刷新http://localhost:1111,可看到demo已经注册到上面。

简单的单机服务治理就此搭建好。

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服务治理界面上那句红字具体怎么回事我暂时还没研究,有知道的可以简单说一下，供大家学习。

可加Q群551807041 一起学习。