《Spring Cloud微服務實戰》——服務治理 Spring Cloud Eureka
阿新 • • 發佈：2019-02-18
一、簡介
Spring cloud Eureka是spring Cloud Netflix微服務套件中的一部分，它基於Netflix Eureka做了二次封裝，主要負責完成微服務架構中的服務治理功能。Spring Cloud通過為Eureka增加了Spring Boot 風格的自動化配置，我們只需要通過簡單的引入依賴和註解配置就能讓Spring Boot構建的微服務應用輕鬆地與Eureka服務治理體系進行整合。
二、搭建服務註冊中心：
1、首先建立一個基礎的Spring boot工程，命名為 eureka-server，並在pom中引入必要內容：
2、通過@EnableEurekaServer 註解啟動一個服務註冊中心供給其他應用進行對話。<?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的依賴--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka-server</artifactId> </dependency> <!--用於測試的，本例可省略--> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <!--依賴管理，用於管理spring-cloud的依賴，其中Camden.SR3是版本號--> <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>
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、在預設配置下，該服務註冊中心會將自己作為客戶端來嘗試註冊他自己，所以我們需要在application.properties中增加相關配置：
4、完成上述操作啟動專案訪問 http://localhost:1111,可看到如下資訊server.port=1111 eureka.instance.hostname=localhost # 由於應用為註冊中心，所以設定為false，代表不想註冊中心註冊自己 eureka.client.register-with-eureka=false #由於註冊中心的職責就是維護服務例項，他不需要去檢索服務，所以設定為false eureka.client.fetch-registry=false eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/
可看到Instances currently registered with Eureka
欄下沒有註冊任何服務。
注：如果啟動報錯可能原因是引入的jar版本有衝突，可修改一下版本號。
三、註冊服務提供者
1、建立一個基礎的Spring boot專案，建立專案名為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的依賴-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
</dependencies>
<!--依賴管理，用於管理spring-cloud的依賴，其中Camden.SR3是版本號-->
<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、建立controller，新增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、在主類（啟動類）裡面新增@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、修改配置檔案application.properties
spring.application.name=demo
eureka.client.serviceUrl.defaultZone=http://localhost:1111/eureka
簡單的單機服務治理就此搭建好。
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服務治理介面上那句紅字具體怎麼回事我暫時還沒研究,有知道的可以簡單說一下，供大家學習。
可加Q群551807041 一起學習。