Eureka-服務註冊於發現
阿新 • • 發佈：2019-02-20
1.什麼是Spring Cloud Eureka?
Spring Cloud Eureka 模組提供的功能是被動式的服務發現.
2.什麼是服務發現?
服務發現就像聊天室一個,每個使用者來的時候去伺服器上註冊,這樣他的好友們就能看到你,你同時也將獲取好友的 上線列表.在微服務中,服務就相當於聊天室的使用者,而服務註冊中心就像聊天室伺服器一樣,目前服務發現的解決 方案有Eureka,Consul,Etcd,Zookeeper,SmartStack,等等. Eureka Client通過HTTP(或者TCP,UDP)去Eureka Server冊和獲取服務列表,為了高可用一般會有多個 Eureka Server組成叢集.Eureka會移除那些心跳檢查未到達的服務.
3.使用Eureka獲取服務呼叫
構建一個Eureka Server,5個Eureka Client(分別提供主語,動詞,量詞,形容詞,名詞服務),再構建一個
Sentence Eureka Client 來用前面五個服務造句.
4.配置
建立eurekaserver工程-服務端
屬於Cloud Discovery的eurekaserver。
pom.xml
<?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.example</groupId> <artifactId>eurekaserver</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>eurekaserver</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.4.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> <spring-cloud.version>Dalston.SR1</spring-cloud.version> </properties> <dependencies> <!--eureka server --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka-server</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>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
EurekaserverApplication.java
@EnableEurekaServer
@SpringBootApplication
public class EurekaserverApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaserverApplication.class, args);
}
}
application.yml
server: port: 8081 eureka: instance: hostname: localhost client: registerWithEureka: false fetchRegistry: false serviceUrl: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ server: # 設為false，關閉自我保護 enable-self-preservation: false # 清理間隔（單位毫秒，預設是60*1000） eviction-interval-timer-in-ms: 10000
建立客戶端：
工程名：eurekaclient
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.example</groupId>
<artifactId>eurekaclient</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>eurekaclient</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<spring-cloud.version>Dalston.SR1</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${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>
EurekaclientApplication.java
@EnableEurekaClient
@SpringBootApplication
public class EurekaclientApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaclientApplication.class, args);
}
}
UserController.java
@RestController
public class UserController {
@Value("${server.port}")
String port;
@RequestMapping("/hi")
public String home(@RequestParam String name) {
return "hi " + name + ",i am from port:" + port;
}
}
application.yml中客戶端對應的serviceUrl是服務管理中心地址，即注入到eurekaserver的訪問地址
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8081/eureka/
server:
port: 8082
spring:
application:
name: service-example1
在建立eurekaclient2，application.yml修改如下：
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8081/eureka/
server:
port: 8083
spring:
application:
name: service-example1
spring.appliacton.name是service-example1也可以修改，但是為了下節ribbon，請勿動。為其餘不變，啟動
親自試試，你會有所進步。