(二)SpringBoot+SpringCloud —— 使用Eureka实现服务注册与发现
2017-07-05 00:00
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一、创建Eureka注册中心(Standalone Mode —— 独立模式)
1.1 创建Eureka Server工程
使用STS创建EurekaServer工程。点击File —— New —— Spring Starter Project后,会弹出创建SpringBoot工程的窗口,输入工程信息后点击下一步。
工程信息可以选择构建工具,这里选择的Maven;
选择Packaging,是Jar包还是War包;
选择Java版本;
选择语言(支持Java、Kotlin和Groovy);
Group、Artifact、Version和Description为maven的相关属性;
最后一个Package是我们定义的工程主类的包,SpringBoot默认会识别该包和其下的子包;
选择SpringBoot的版本,并搜索eureka,勾选Eureka Server后,点击Finish创建工程。
创建好的工程目录结构如下:
工程会自动为我们创建maven结构的工程,并且创建了OwlBookstoreEurekaServerApplication类和对应的测试类,在resources文件夹下还有一个空白的application.properties属性文件。
1.2 pom文件
为了将工程作为Eureka注册中心,我们在创建工程时引入了Eureka Server包,在pom文件中可以看到:<?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>cn.net.bysoft</groupId> <artifactId>owl-bookstore-eureka-server</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <name>owl-bookstore-eureka-server</name> <description>owl-bookstore-eureka-server</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-server</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot- 3ff1 starter-test</artifactId> <scope>test</scope> </dependency> <!-- 热部署 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> <optional>true</optional> <scope>true</scope> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${spring-cloud.version}</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> <!-- 热部署插件 --> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <fork>true</fork> </configuration> </plugin> </plugins> </build> </project>
1.3 application文件
接下来,我们修改配置信息,启动Eureka Server。SpringBoot支持yml格式的配置文件,在resources中创建一个application.yml文件,并编写如下内容:
spring: application: name: eureka-server server: port: 8761 eureka: instance: hostname: localhost client: registerWithEureka: false fetchRegistry: false serviceUrl: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ debug: true logging: file: wol-bookstore-eureka-server.log level: root: info
spring:application:name:给应用定义一个名称;
server:port:是应用的端口号;
eureka:instance:hostname:是应用所在的主机名;
eureka:client:registerWithEureka:用于应用是注册中心,所以不向注册中心注册自己;
eureka:client:fetchRegistry:用于应用是注册中心,所以不需要去检索服务;
eureka:client:serviceUrl:defaultZone:定义注册中心的地址;
debug:打开日志功能;
logging:file:日志文件指向当前应用的目录;
logging:level:root:输出级别为info;
1.4 修改主类
最后用@EnableEurekaServer修饰主类OwlBookstoreEurekaServerApplication。package cn.net.bysoft.owl.bootstore; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; /** * <ul> * <li>使用<em>@EnableEurekaServer</em>来修饰主类;</li> * </ul> * * @author xuepeng */ @SpringBootApplication @EnableEurekaServer public class OwlBookstoreEurekaServerApplication { public static void main(String[] args) { SpringApplication.run(OwlBookstoreEurekaServerApplication.class, args); } }
1.5 运行注册中心
使用SpringBootApp运行程序,程序运行后访问地址http://localhost:8761来进入注册中心。这里需要注意,虽然配置的是http://${eureka.instance.hostname}:${server.port}/eureka/,但是注册中心的地址不带有/eureka。到此,Eureka注册中心已经运行成功了。
二、服务注册
2.1 创建service-user工程
创建一个服务,命名为owl-bookstore-service-user。2.2 pom文件
在pom文件中,加入spring-cloud-starter-eureka依赖。<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>cn.net.bysoft</groupId> <artifactId>owl-bookstore-service-user</artifactId> <version>1.0-SNAPSHOT</version> <packaging>jar</packaging> <name>owl-bookstore-service-user</name> <description>owl-bookstore-service-user</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.4.RELEASE</version> <relativePath/> <!-- lookup parent from repository --> </parent> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding> <java.version>1.8</java.version> <spring-cloud.version>Dalston.SR1</spring-cloud.version> </properties> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>${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>
2.3 application文件配置
eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/ server: port: 7001 spring: application: name: SERVICE-USER
eureka:client:serviceUrl:defaultZone:设置注册中心的地址;
server:port:服务的端口号;
spring:application:name:服务的名称,该名称不要和其他的服务重名;
2.4 编写简单的业务demo
cn.net.bysoft.owl.bookstore.service.user包下存放着主类,使用@EnableDiscoveryClient修饰主类:
package cn.net.bysoft.owl.bookstore.service.user; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; @SpringBootApplication @EnableDiscoveryClient public class OwlBookstoreServiceUserApplication { public static void main(String[] args) { SpringApplication.run(OwlBookstoreServiceUserApplication.class, args); } }
cn.net.bysoft.owl.bookstore.service.user.entity包下存放user服务的实体类:
package cn.net.bysoft.owl.bookstore.service.user.entity; public class User { private final long id; private final String name; public User(long id, String name) { this.id = id; this.name = name; } public long getId() { return id; } public String getName() { return name; } }
cn.net.bysoft.owl.bookstore.service.user.facade包下存放着具体的user服务:
package cn.net.bysoft.owl.bookstore.service.user.facade; import java.util.List; import cn.net.bysoft.owl.bookstore.service.user.entity.User; public interface UserService { List<User> getAll(); }
cn.net.bysoft.owl.bookstore.service.user.facade.impl包下存放着服务的实现,用@RestController修饰类,用@RequestMapping修饰方式,@Value用来读取application.yml文件中的server.port的值:
package cn.net.bysoft.owl.bookstore.service.user.facade.impl; import java.util.ArrayList; import java.util.List; import org.springframework.beans.factory.annotation.Value; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController; import cn.net.bysoft.owl.bookstore.service.user.entity.User; import cn.net.bysoft.owl.bookstore.service.user.facade.UserService; @RestController public class UserServiceImpl implements UserService { @Value("${server.port}") String port; @RequestMapping(value = "users", method = RequestMethod.GET) @Override public List<User> getAll() { List<User> users = new ArrayList<>(); users.add(new User(1L, port)); return users; } }
2.5 启动服务
启动服务,并访问服务地址:http://localhost:7001/users,测试服务是否启动成功:通过上图可以看到服务已经启动成功,接下来刷新注册中心,会发现服务已经注册到Eureka Server中了:
至此,服务的注册已经完成。
三、服务发现与使用
3.1 创建消费服务的工程
这里创建一个bookstore后台管理的springboot工程,选择war包方式:3.2 pom文件
引入以下依赖:spring-cloud-starter-eureka;
spring-boot-starter-web;
spring-cloud-starter-ribbon;
pom文件的全部内容如下:
<?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> <groupId>cn.net.bysoft</groupId> <artifactId>owl-bookstore-web-console</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <name>owl-bookstore-web-console</name> <description>owl-bookstore-service-user</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.cloud</groupId> <artifactId>spring-cloud-starter-ribbon</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> <scope>provided</scope> </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>
3.3 application文件配置
spring: application: name: owl-bookstore-web-console eureka: client: serviceUrl: defaultZone: http://localhost:8761/eureka/ server: port: 8000
连接到数据中心,并将应用端口设置为8000。
3.4 编写消费(使用)服务的代码
cn.net.bysoft.owl.bookstore.web.console包下存放着主类,使用@EnableDiscoveryClient来修饰它,在类中定义了一个RestTemplate,使用它以rest风格来消费(使用)服务,这个类还被@LoadBalanced所修饰,意为启动负载均衡。
package cn.net.bysoft.owl.bookstore.web.console; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.web.client.RestTemplate; @SpringBootApplication @EnableDiscoveryClient public class OwlBookstoreWebConsoleApplication { @Bean @LoadBalanced RestTemplate restTemplate() { return new RestTemplate(); } public static void main(String[] args) { SpringApplication.run(OwlBookstoreWebConsoleApplication.class, args); } }
cn.net.bysoft.owl.bookstore.web.console.service包内存放的是业务实现类,自动装配RestTemplate,并以rest风格,通过http协议,向服务发送get请求。
此处,uri的地址为服务的[注册名]/[requestmapping]:
package cn.net.bysoft.owl.bookstore.web.console.service; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.web.client.RestTemplate; @Service public class UserService { 3ff0 @Autowired RestTemplate restTemplate; public String getAll() { return restTemplate.getForEntity("http://SERVICE-USER/users", String.class).getBody(); } }
cn.net.bysoft.owl.bookstore.web.console.controller包内存放着控制器:
package cn.net.bysoft.owl.bookstore.web.console.controller; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import cn.net.bysoft.owl.bookstore.web.console.service.UserService; @RestController(value = "/") public class UserController { @Autowired UserService userService; @RequestMapping(value = "users") public String index() { return userService.getAll() + " ==> console"; } }
3.5 启动应用消费服务
为了测试负载均衡,我们通过命令行的方式启动两个service-user:首先用maven install将service-user打包成jar包;
进入service-user的target文件夹下;
打开cmd,输入java -jar owl-bookstore-service-user-1.0-SNAPSHOT.jar --server.port=7001;
再打开一个cmd,输入打开cmd,输入java -jar owl-bookstore-service-user-1.0-SNAPSHOT.jar --server.port=7002;
现在刷新注册中心就会发现SERVICE-USER有两个:
随后,启动owl-bookstore-web-console应用,刷新注册中心,会看到该应用也注册成功:
现在,访问http://localhost:8000/users,并刷新页面,会看到应用通过轮询的方式消费7001端口与7002端口的服务了。
以上,就是服务注册与消费的简单demo。
Github:https://github.com/XuePeng87/owl-bookstore
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