1、springcloud简介
2、注册中心eureka
Springcloud简介
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。
详细介绍: https://baike.so.com/doc/25751000-26884657.html
配套参考资料:
https://projects.spring.io/spring-cloud/ springcloud项目官方主页
https://springcloud.cc/ springcloud中文网 有很详细的翻译文档
http://springcloud.cn/ springcloud中文论坛
Springcloud版本pom文件生成可借助网站:
原有的单体项目最终会被演化成下面
这样的架构解决了单体项目几点问题:
1、zuul网关解决了服务调用安全性的问题
2、服务注册与发现(注册中心)eureka解决了各层服务耦合问题,它是微服务架构的核心,有它才能将单体项目拆解成微服务架构
3、Eureka集群解决了微服务中,注册中心宕机产生的问题
4、Ribbon负载均衡及Feign消费者调用服务,减小了各微服务服务器的访问压力,默认采用了经典的轮询机制
5、熔断器Hystrix解决了,微服务架构中服务器雪崩现象
6、服务监控(单机Dashboard与集群turbine),方便运维人员查看微服务架构项目运行时,各个服务器的运行状态
7、服务配置中心(springcloud config),用来通过github统一管理各个微服务的配置文件(yml文件)
详情查阅可见中的images文件夹
入门案例
最简单的微服务架构会有四个工程
父工程:spring cloud
通用模块(M):microservice-common
服务提供者(C):microservice-student-provider-1001
服务消费者(C):microservice-student-consumer-80
微服务架构注意点:
1、springboot、springcloud版本在父工程定义;
2、由于通用模块无需操作数据库,springboot启动默认会读取数据库,所以得添加以下注解 @SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class});
3、分布式jpa需要在启动类上添加@EntityScan("com.javaxl.*.*");
4、消费者需要添加配置类获取org.springframework.web.client.RestTemplate,springcloud底层是通过RestTemplate来调用提供者的服务的。
传统项目拆分成微服务架构图
创建父工程spring cloud
父工程是一个maven项目,一般创建方式即可,父工程的主要用途是锁定pom依赖包版本。由于springcloud2X停止更新,这里我们采用稳定的低版本,配套的springboot版本为1x版本。
pom配置如下(父工程为maven工程,子工程为springboot工程)
<?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.hmc</groupId> <artifactId>springcloud</artifactId> <version>1.0-SNAPSHOT</version> <packaging>pom</packaging> <name>springcloud</name> <!-- FIXME change it to the project's website --> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <druid.version>1.1.10</druid.version> </properties> <!--锁定pom依赖jar包,但不实际引入--> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Edgware.SR4</version> <type>pom</type> <scope>import</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>1.5.13.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> <!-- 连接池 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>${druid.version}</version> </dependency> </dependencies> </dependencyManagement> </project>
创建通用模块microservice-common
通用模块主要存放实体类、工具包等被整个微服务框架所使用的代码。创建一个简单的springboot模块即可。相关代码如下
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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.hmc</groupId> <artifactId>springcloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>microservice-common</artifactId> <properties> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> <exclusions> <exclusion> <groupId>org.junit.vintage</groupId> <artifactId>junit-vintage-engine</artifactId> </exclusion> </exclusions> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
MicroserviceCommonApplication.java
package com.hmc.microservicecommon; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration; import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration; @SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class}) public class MicroserviceCommonApplication { public static void main(String[] args) { SpringApplication.run(MicroserviceCommonApplication.class, args); } }
package com.hmc.microservicecommon.entity; import javax.persistence.*; import java.io.Serializable; @Entity @Table(name="t_springboot_student") public class Student implements Serializable { private static final long serialVersionUID = 1L; @Id @GeneratedValue private Integer id; @Column(length=50) private String name; @Column(length=50) private String grade; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getGrade() { return grade; } public void setGrade(String grade) { this.grade = grade; } }
创建服务提供者microservice-student-provider-1001
创建一个简单的springboot模块,这里服务提供者需要操作数据库并且被浏览器所访问,固需要添加相关配置如下
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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.hmc</groupId> <artifactId>springcloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>microservice-student-provider-1001</artifactId> <properties> <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-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> </dependency> <!-- 修改后立即生效,热部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <dependency> <groupId>com.hmc</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <!--添加注册中心Eureka相关配置--> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-eureka</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-config</artifactId> </dependency> <!-- actuator监控引入 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
server: port: 1001 context-path: / spring: datasource: type: com.alibaba.druid.pool.DruidDataSource driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/book?useUnicode=true&characterEncoding=utf8 username: root password: 123 jpa: hibernate: ddl-auto: update show-sql: true
MicroserviceStudentProvider1001Application.java
package com.hmc.microservicestudentprovider1001; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.autoconfigure.domain.EntityScan; @EntityScan("com.hmc.*.*") @SpringBootApplication public class MicroserviceStudentProvider1001Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentProvider1001Application.class, args); } }
package com.hmc.microservicestudentprovider1001.repository; import com.javaxl.microservicecommon.entity.Student; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.data.jpa.repository.JpaSpecificationExecutor; public interface StudentRepository extends JpaRepository<Student, Integer>, JpaSpecificationExecutor<Student> { }
package com.hmc.microservicestudentprovider1001.service; import com.javaxl.microservicecommon.entity.Student; import java.util.List; public interface StudentService { public void save(Student student); public Student findById(Integer id); public List<Student> list(); public void delete(Integer id); }
package com.hmc.microservicestudentprovider1001.service.impl; import com.hmc.microservicecommon.entity.Student; import com.hmc.microservicestudentprovider1001.repository.StudentRepository; import com.hmc.microservicestudentprovider1001.service.StudentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import java.util.List; @Service public class StudentServiceImpl implements StudentService { @Autowired private StudentRepository studentRepository; @Override public void save(Student student) { studentRepository.save(student); } @Override public Student findById(Integer id) { return studentRepository.findOne(id); } @Override public List<Student> list() { return studentRepository.findAll(); } @Override public void delete(Integer id) { studentRepository.delete(id); } }
StudentProviderController.java
package com.hmc.microservicestudentprovider1001.controller; import com.hmc.microservicecommon.entity.Student; import com.hmc.microservicestudentprovider1001.service.StudentService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/student") public class StudentProviderController { @Autowired private StudentService studentService; @PostMapping(value="/save") public boolean save(Student student){ try{ studentService.save(student); return true; }catch(Exception e){ return false; } } @GetMapping(value="/list") public List<Student> list(){ return studentService.list(); } @GetMapping(value="/get/{id}") public Student get(@PathVariable("id") Integer id){ return studentService.findById(id); } @GetMapping(value="/delete/{id}") public boolean delete(@PathVariable("id") Integer id){ try{ studentService.delete(id); return true; }catch(Exception e){ return false; } } }
创建服务消费者microservice-student-consumer-80
服务消费者主要是通过restful api来调用提供者的接口,固不需要不需要操作数据库,相关配置如下
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.hmc</groupId> <artifactId>springcloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>microservice-student-consumer-80</artifactId> <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-data-jpa</artifactId> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-tomcat</artifactId> </dependency> <!-- 修改后立即生效,热部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <dependency> <groupId>com.hmc</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>com.hmc</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
server: port: 80 context-path: /
MicroserviceStudentConsumer80Application.java
package com.hmc.microservicestudentconsumer80; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration; import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration; @SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class}) public class MicroserviceStudentConsumer80Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentConsumer80Application.class, args); } }
package com.hmc.microservicestudentconsumer80.config; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.client.RestTemplate; @Configuration public class SpringCloudConfig { @Bean public RestTemplate getRestTemplate(){ return new RestTemplate(); } }
StudentConsumerController.java
package com.hmc.microservicestudentconsumer80.controller; import com.hmc.microservicecommon.entity.Student; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; import org.springframework.web.client.RestTemplate; import java.util.List; @RestController @RequestMapping("/student") public class StudentConsumerController { private final static String SERVER_IP_PORT = "http://localhost:1001"; @Autowired private RestTemplate restTemplate; @PostMapping(value="/save") private boolean save(Student student){ return restTemplate.postForObject(SERVER_IP_PORT+"/student/save", student, Boolean.class); } @GetMapping(value="/list") public List<Student> list(){ return restTemplate.getForObject(SERVER_IP_PORT+"/student/list", List.class); } @GetMapping(value="/get/{id}") public Student get(@PathVariable("id") Integer id){ return restTemplate.getForObject(SERVER_IP_PORT+"/student/get/"+id, Student.class); } @GetMapping(value="/delete/{id}") public boolean delete(@PathVariable("id") Integer id){ try{ restTemplate.getForObject(SERVER_IP_PORT+"/student/delete/"+id, Boolean.class); return true; }catch(Exception e){ return false; } } }
关于如何配置RunDashboard
https://www.cnblogs.com/yangtianle/p/8818255.html
成功结果图如下
初识eureka
Eureka简介:
Eureka是Netflix开发的服务发现框架,本身是一个基于REST的服务,主要用于定位运行在AWS域中的中间层服务,以达到负载均衡和中间层服务故障转移的目的。SpringCloud将它集成在其子项目spring-cloud-netflix中,以实现SpringCloud的服务发现功能。
Eureka包含两个组件:Eureka Server和Eureka Client。
Eureka Server提供服务注册服务,各个节点启动后,会在Eureka Server中进行注册,这样EurekaServer中的服务注册表中将会存储所有可用服务节点的信息,服务节点的信息可以在界面中直观的看到。
Eureka Client是一个java客户端,用于简化与Eureka Server的交互,客户端同时也就别一个内置的、使用轮询(round-robin)负载算法的负载均衡器。
在应用启动后,将会向Eureka Server发送心跳,默认周期为30秒,如果Eureka Server在多个心跳周期内没有接收到某个节点的心跳,Eureka Server将会从服务注册表中把这个服务节点移除(默认90秒)。
Eureka Server之间通过复制的方式完成数据的同步,Eureka还提供了客户端缓存机制,即使所有的Eureka Server都挂掉,客户端依然可以利用缓存中的信息消费其他服务的API。综上,Eureka通过心跳检查、客户端缓存等机制,确保了系统的高可用性、灵活性和可伸缩性。
类似zookeeper,Eureka也是一个服务注册和发现组件,是SpringCloud的一个优秀子项目,不过比较坑的是,Eureka2版本已经停止更新了。但是Eureka1版本还是很稳定,功能足够用,所以还是有必要学习下。
但是这里有几个常用的服务注册与发现组件比对;
服务注册与发现原理。
Eureka的使用
前面说过eureka是c/s模式的 server服务端就是服务注册中心,其他的都是client客户端,服务端用来管理所有服务,客户端通过注册中心,来调用具体的服务;
我们先来搭建下服务端,也就是服务注册中心;
新建 module microservice-eureka-server-2001;
在pom文件中加入eureka-server依赖;
在yml文件中添加Eureka服务端相关信息;
在启动类中添加@EnableEurekaServer注解;
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>com.hmc</groupId> <artifactId>springcloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>microservice-eureka-server-2001</artifactId> <properties> <java.version>1.8</java.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-starter-test</artifactId> <scope>test</scope> </dependency> <!-- 修改后立即生效,热部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
server: port: 2001 context-path: / eureka: instance: hostname: localhost #eureka注册中心实例名称 client: register-with-eureka: false #false 由于该应用为注册中心,所以设置为false,代表不向注册中心注册自己。 fetch-registry: false #false 由于注册中心的职责就是维护服务实例,它并不需要去检索服务,所以也设置为false service-url: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #设置与Eureka注册中心交互的地址,查询服务和注册服务用到
MicroserviceEurekaServer2001Application.java
package com.hmc.microserviceeurekaserver2001; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer; @EnableEurekaServer @SpringBootApplication public class MicroserviceEurekaServer2001Application { public static void main(String[] args) { SpringApplication.run(MicroserviceEurekaServer2001Application.class, args); } }
测试连接
搭建成功截图如下
向Eureka中注册服务提供者
这里我们在原来的服务提供者项目 microservice-student-provider-1001 上面直接修改: