目的:
1.springcloud簡介
2.注冊中心eureka
springcloud簡介
推薦一個springcloud講解詳細的博客:https://blog.csdn.net/qq32933432/article/details/89918264
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簡介
Spring Cloud是一系列框架的有序集合。它利用Spring Boot的開發便利性巧妙地簡化了分布式系統基礎設施的開發,如服務發現注冊、配置中心、消息總線、負載均衡、斷路器、數據監控等,都可以用Spring Boot的開發風格做到一鍵啟動和部署。Spring Cloud並沒有重復制造輪子,它只是將目前各家公司開發的比較成熟、經得起實際考驗的服務框架組合起來,通過Spring Boot風格進行再封裝屏蔽掉了復雜的配置和實現原理,最終給開發者留出了一套簡單易懂、易部署和易維護的分布式系統開發工具包。
詳細介紹: https://baike.so.com/doc/25751000-26884657.html
配套參考資料:
https://projects.spring.io/spring-cloud/ springcloud項目官方主頁
https://springcloud.cc/ springcloud中文網 有很詳細的翻譯文檔
http://springcloud.cn/ springcloud中文論壇
Springcloud版本pom文件生成可借助網站:
原有的單體項目最終會被演化成下面

這樣的架構解決了單體項目幾點問題:
1、zuul網關解決了服務調用安全性的問題
2、服務注冊與發現(注冊中心)eureka解決了各層服務耦合問題,它是微服務架構的核心,有它才能將單體項目拆解成微服務架構
3、Eureka集群解決了微服務中,注冊中心宕機產生的問題
4、Ribbon負載均衡及Feign消費者調用服務,減小了各微服務服務器的訪問壓力,默認采用了經典的輪詢機制
5、熔斷器Hystrix解決了,微服務架構中服務器雪崩現象
6、服務監控(單機Dashboard與集群turbine),方便運維人員查看微服務架構項目運行時,各個服務器的運行狀態
7、服務配置中心(springcloud config),用來通過github統一管理各個微服務的配置文件(yml文件)
入門案例
最簡單的微服務架構會有四個工程
父工程:htSpringCloud
通用模塊(M):microservice-common
服務提供者(C):microservice-student-provider-1001
服務消費者(C):microservice-student-consumer-80
微服務架構注意點:
1、springboot、springcloud版本在父工程定義;
2、由於通用模塊無需操作數據庫,springboot啟動默認會讀取數據庫,所以得添加以下注解 @SpringBootApplication(exclude={DataSourceAutoConfiguration.class, HibernateJpaAutoConfiguration.class});
3、分布式jpa需要在啟動類上添加@EntityScan("com.javaxl.*.*");
4、消費者需要添加配置類獲取org.springframework.web.client.RestTemplate,springcloud底層是通過RestTemplate來調用提供者的服務的。
傳統項目拆分成微服務架構圖:

創建父工程htSpringCloud



父工程是一個maven項目,一般創建方式即可,父工程的主要用途是鎖定pom依賴包版本。由於springcloud2X停止更新,這里我們采用穩定的低版本,配套的springboot版本為1x版本。
Pom.xml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 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.ht</groupId> <artifactId>htSpringCloud</artifactId> <version>1.0-SNAPSHOT</version> <name>htSpringCloud</name> <url>http://www.example.com</url> <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> <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> <!-- 連接池 --> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid-spring-boot-starter</artifactId> <version>${druid.version}</version> </dependency> </dependencies> </dependencyManagement> </project>
創建通用模塊microservice-common




通用模塊主要存放實體類、工具包等被整個微服務框架所使用的代碼。創建一個簡單的springboot模塊即可。
相關代碼如下
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.ht</groupId> <artifactId>htSpringCloud</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-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> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <!--被依賴的公共模塊必須加上這個,打包之后啟動, 選擇后面帶EXE的啟動,依賴該模塊的其他模塊就不會因為找不到依賴而打包出錯--> <classifier>exe</classifier> </configuration> </plugin> </plugins> </build> </project>
MicroserviceCommonApplication.java
package com.ht.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); } }
Student
package com.ht.microservicecommon.entity; import javax.persistence.*; import java.io.Serializable; @Entity @Table(name="t_springcloud_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; } }
創建服務提供者microservice-student-provider-1001


創建一個簡單的springboot模塊,這里服務提供者需要操作數據庫並且被瀏覽器所訪問,固需要添加相關配置如下
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.ht</groupId> <artifactId>htSpringCloud</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,熱部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <dependency> <groupId>com.ht</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> <scope>compile</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
application.yml
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/test?useUnicode=true&characterEncoding=utf8 username: root password: root jpa: hibernate: ddl-auto: update show-sql: true
MicroserviceStudentProvider1001Application.java
package com.ht.microservicestudentprovider1001; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.boot.autoconfigure.domain.EntityScan; @EntityScan("com.ht.*.*") @SpringBootApplication public class MicroserviceStudentProvider1001Application { public static void main(String[] args) { SpringApplication.run(MicroserviceStudentProvider1001Application.class, args); } }
StudentRepository.java
package com.ht.microservicestudentprovider1001.repository; import com.ht.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> { }
StudentService
package com.ht.microservicestudentprovider1001.service; import com.ht.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); }
StudentServiceImpl.java
package com.ht.microservicestudentprovider1001.service.impl; import com.ht.microservicecommon.entity.Student; import com.ht.microservicestudentprovider1001.repository.StudentRepository; import com.ht.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.ht.microservicestudentprovider1001.controller; import com.ht.microservicecommon.entity.Student; import com.ht.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; } } }
創建服務消費者microservice-student-consumer-80


服務消費者主要是通過restful api來調用提供者的接口,固不需要不需要操作數據庫,相關配置如下
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.ht</groupId> <artifactId>htSpringCloud</artifactId> <version>1.0-SNAPSHOT</version> </parent> <artifactId>microservice-student-consumer-80</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> <!-- 修改后立即生效,熱部署 --> <dependency> <groupId>org.springframework</groupId> <artifactId>springloaded</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-devtools</artifactId> </dependency> <dependency> <groupId>com.ht</groupId> <artifactId>microservice-common</artifactId> <version>1.0-SNAPSHOT</version> <scope>compile</scope> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project>
application.yml
server:
port: 80
context-path: /
MicroserviceStudentConsumer80Application.java
package com.ht.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); } }
SpringCloudConfig.java
package com.ht.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.ht.microservicestudentconsumer80.controller; import com.ht.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; } } }
關於如何配置RunDashboard
https://www.cnblogs.com/yangtianle/p/8818255.html
成功結果圖如下
http://localhost:1001/student/list


注冊中心eureka
Eureka簡介:
Eureka是Netflix開發的服務發現框架,本身是一個基於REST的服務,主要用於定位運行在AWS域中的中間層服務,以達到負載均衡和中間層服務故障轉移的目的。SpringCloud將它集成在其子項目spring-cloud-netflix中,以實現SpringCloud的服務發現功能。
Eureka包含兩個組件:Eureka Server和Eureka Client。
Eureka Server提供服務注冊服務,各個節點啟動后,會在Eureka Server中進行注冊,這樣EurekaServer中的服務注冊表中將會存儲所有可用服務節點的信息,服務節點的信息可以在界面中直觀的看到。
Eureka Client是一個java客戶端,用於簡化與Eureka Server的交互,客戶端同時也就別一個內置的、使用輪詢(round-robin)負載算法的負載均衡器。
在應用啟動后,將會向Eureka Server發送心跳,默認周期為30秒,如果Eureka Server在多個心跳周期內沒有接收到某個節點的心跳,Eureka Server將會從服務注冊表中把這個服務節點移除(默認90秒)。
Eureka Server之間通過復制的方式完成數據的同步,Eureka還提供了客戶端緩存機制,即使所有的Eureka Server都掛掉,客戶端依然可以利用緩存中的信息消費其他服務的API。綜上,Eureka通過心跳檢查、客戶端緩存等機制,確保了系統的高可用性、靈活性和可伸縮性
類似zookeeper,Eureka也是一個服務注冊和發現組件,是SpringCloud的一個優秀子項目,不過比較坑的是,Eureka2版本已經停止更新了。但是Eureka1版本還是很穩定,功能足夠用,所以還是有必要學習下。
但是這里有幾個常用的服務注冊與發現組件比對;

服務注冊與發現原理:

Eureka的使用
前面說過eureka是c/s模式的 server服務端就是服務注冊中心,其他的都是client客戶端,服務端用來管理所有服務,客戶端通過注冊中心,來調用具體的服務;
我們先來搭建下服務端,也就是服務注冊中心;
新建 module microservice-eureka-server-2001;
在pom文件中加入eureka-server依賴;
在yml文件中添加Eureka服務端相關信息;
在啟動類中添加@EnableEurekaServer注解;


導入相關pom依賴
<?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.ht</groupId> <artifactId>htSpringCloud</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,熱部署 --> <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>
application.yml
server: port: 2001 context-path: / eureka: instance: hostname: localhost #eureka注冊中心實例名稱 client: register-with-eureka: false #false 由於該應用為注冊中心,所以設置為false,代表不向注冊中心注冊自己。 fetch-registry: false #false 由於注冊中心的職責就是維護服務實例,它並不需要去檢索服務,所以也設置為false service-url: defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/ #設置與Eureka注冊中心交互的地址,查詢服務和注冊服務用到
啟動類MicroserviceEurekaServer2001Application
package com.ht.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); } }
測試連接
http://localhost:2001/

向Eureka中注冊服務提供者
這里我們在原來的服務提供者項目 microservice-student-provider-1001 上面直接修改:
首先pom.xml修改,加上eureka客戶端依賴:

<!--添加注冊中心Eureka相關配置--> <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>
然后application.yml上加上配置:
eureka: instance: hostname: localhost appname: microservice-student instance-id: microservice-student:1001 prefer-ip-address: true client: service-url: defaultZone: http://localhost:2001/eureka
這里的defaultZone要和前面服務注冊中心的暴露地址一致;
最后 啟動類加上一個注解 @EnableEurekaClient;

然后我們測試下,先啟動服務注冊中心,再啟動這個服務提供者;
服務提供者成功注冊截圖如下

點擊實例狀態結果如下是看不到內容的所以我們需要導入actuator監控依賴

解決方案如下
1、首先在服務提供者項目pom.xml里加入actuator監控依賴:
2、最后服務提供者項目application.yml加上info配置:
pom依賴中添加:
<!-- actuator監控引入 --> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-actuator</artifactId> </dependency>
yml文件中添加
info: groupId: com.ht.htSpringCloud artifactId: microservice-student-provider-1001 version: 1.0-SNAPSHOT userName: http://ht.com phone: 123456
效果如下:

