Spring Cloud的基本认识和使用Spring Cloud的基本教程

认识Spring Cloud

Spring Cloud简单来说就是一个微服务相关的框架,至于什么是微服务,简单来说就是一个整体项目由多个单独运行的小项目构成,每个小项目负责一个或多个功能,每个小项目有1个或者1个以上运行实例,项目之间可以相互调用。如果有接触Dubbo,那么就可以很容易理解,Dubbo是一个提供不同项目相互调用的框架,同时Dubbo需要依赖于Zookeeper,所以说Spring Cloud做的事和Dubbo类似,却又有很大不同,但是它们的目的确实相同的,那就是提供不同项目之间的调用和负载均衡

Spring Cloud 常用组件

Spring Cloud Eureka

Spring Cloud EurekaSpring Cloud Netflix 微服务套件中的一部分,它基于Netflix Eureka 做了二次分装,由两个组件组成:Eureka服务器和Eureka客户端。 Eureka服务器用作服务注册服务器。Eureka客户端是一个Java客户端,用来简化与服务器的交互、作为轮询负载均衡器,并提供服务的故障切换支 持。Netflix在其生产环境中使用的是另外的客户端,它提供基于流量、资源利用率以及出错状态的加权负载均衡,其中Eureka Server角色相当于Dubbo的Zookeeper,Eureka Client相当于服务提供者和调用者

Spring Cloud Zookeeper

对Zookeeper的封装,使之能配置其它Spring Cloud的子项目使用

Spring Cloud Zuul

类似nginx,反向代理的功能,不过netflix自己增加了一些配合其他组件的特性。

Spring Cloud Hystrix

断路器可以防止一个应用程序多次试图执行一个操作,即很可能失败,允许它继续而不等待故障恢复或者浪费 CPU 周期,而它确定该故障是持久的。断路器模式也使应用程序能够检测故障是否已经解决。如果问题似乎已经得到纠正​​,应用程序可以尝试调用操作。

Spring Cloud Security

对Spring Security的封装,并能配合Netflix使用

Spring Cloud Bus

分布式消息队列,是对Kafka, MQ的封装

Spring Cloud Config

将配置信息中央化保存, 配置Spring Cloud Bus可以实现动态修改配置文件

其他组件可以在官网或者中文网站查看

中文文档:https://springcloud.cc/

官方网站:http://projects.spring.io/spring-cloud/#quick-start

使用Spring Cloud搭建简易微服务项目

要使用Spring Cloud搭建项目,首先需要考虑微服务的基础结构,然后再根据基础结构来搭建项目  EurekaClient,ribbon,feign EurekaServer可以是一台或多台,EurekaClient也可以是一台或多台,同时EurekaClient既可以是服务提供者也可以调用者,对于doubbo比较熟悉的人,可以吧EurekaServer当做Zookeeper,EurekaClient为我们的项目,本文的demo是基于spring boot的,如果不会spring boot的可以去看看我之前的文章基于Maven的Springboot+Mybatis+Druid+Swagger2+mybatis-generator框架环境搭建

创建EurekaServer

EurekaServer的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>wang.raye</groupId>
    <artifactId>springcloudserver</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springcloudServer</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.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.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>

主要是对项目加入了eureka-server的支持

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>

application添加注解

@EnableEurekaServer

Application.java

package wang.raye.springcloudserver;

import org.springframework.boot.SpringApplication;  
import org.springframework.boot.autoconfigure.SpringBootApplication;  
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@EnableEurekaServer
@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

相对于普通的的Application只是对了一个注解而已,当然仅仅这样也不行,熟悉doubbo的人都知道Zookeeper是有端口的,所以我们需要在application.yml中配置好EurekaServer的端口

配置如下:

    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

其中${}是可以用静态变量代替的,不过这里为了跟项目保持一致,所以直接用的项目的名字和端口,application.yml详细配置如下:

server:  
  port: 8761

eureka:  
  instance:
    hostname: localhost
  client:
    registerWithEureka: false
    fetchRegistry: false
    serviceUrl:
      defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

访问http://localhost:8761 可以看到如下界面,显示EurekaServer当前状态 EurekaServer状态

创建EurekaClient

为了显示效果,所以我们创建2个EurekaClient项目,2个项目相互调用,因为Spring Cloud支持2种调用方式,Ribbon和Feign,所以2个项目,我们分别用2种方式来调用,2种方式提供服务的方法都是相同的,只是在调用其他项目的方法上面稍有不同而已

首先创建Ribbon方式的client

ribbon

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>wang.raye</groupId>
    <artifactId>springcloud.ribbon</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.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.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>  

其中

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>

是提供服务的相关依赖

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-ribbon</artifactId>
        </dependency>

是调用方式的依赖,当然一个项目可以同时使用ribbon和feign2个方法调用

application.java

package wang.raye.springcloud.ribbon;

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;

/**
 * Created by Raye on 2017/5/22.
 */
@SpringBootApplication
@EnableEurekaClient
public class Application {  
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    @LoadBalanced
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

}

@EnableEurekaClient 是提供向注册中心表明此服务需要被注册的注解

Conntroller.java

package wang.raye.springcloud.ribbon;

import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RestController;  
import org.springframework.web.client.RestTemplate;

/**
 * Created by Raye on 2017/5/22.
 */
@RestController
public class Controller {

    @Autowired
    private RestTemplate template;
    @RequestMapping("hello")
    public String ribbon(String name){
        return template.getForObject("http://SERVICE-HI/ribbonhello?name="+name,String.class);
    }

    @RequestMapping("feignhello")
    public String hello(String name){
        return "hello "+name+" this is ribbon spring cloud";
    }
}

feignhello是被远程调用的接口,hello接口是远程调用另外一个项目的接口,其中RestTemplate 是配置文件写好就可以自动注入的,http://SERVICE-HI 其中SERVICE-HI是被调用的项目配置的名字,ribbonhello是接口地址

application.yml

eureka:  
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
server:  
  port: 8764
spring:  
  application:
    name: service-ribbon

eureka相关配置是配置的注册中心的地址,而service-ribbon是配置其他项目访问的地址的,ribbon访问这样配置就是ok 的了,直接运行Application.java就可以了,接下来看看feign方式的client

fegin
<?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>wang.raye.springcloud</groupId>
    <artifactId>client</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>springcloudClient</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.3.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.RELEASE</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-aop</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>  

同理,如果需要feign方式调用,需要先添加依赖

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>

Application.java

package wang.raye.springcloudclient;

import org.springframework.boot.SpringApplication;  
import org.springframework.boot.autoconfigure.SpringBootApplication;  
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;  
import org.springframework.cloud.netflix.feign.EnableFeignClients;

/**
 * Created by Raye on 2017/5/22.
 */
@EnableEurekaClient
@SpringBootApplication
@EnableFeignClients
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

}

这里多了一个注解就是@EnableFeignClients,必须要这个注解,定义的接口才能正确注入引用类中的,有了Application.java类后,需要先定义一个远程调用服务器的接口类,如下:

HelloService.java

package wang.raye.springcloudclient;

import org.springframework.cloud.netflix.feign.FeignClient;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RequestMethod;  
import org.springframework.web.bind.annotation.RequestParam;

/**
 * Fegin 可被调用的服务申明
 * Created by Raye on 2017/6/26.
 */
@FeignClient(value = "service-ribbon")
public interface HelloService {

    @RequestMapping(value = "/feignhello",method = RequestMethod.GET)
    String sayHelloFromRibbon(@RequestParam(value = "name") String name);
}

这里是定义了一个接口,但是具体接口实现是由远程实现的,也就是通过调用其他项目实现的,其中FeignClient注解的值跟ribbon调用的值一样,都是被调用项目的项目名字,RequestMapping就很明显了,跟Controller用的是同一个,不过这里是表明远程调用这个方法而已

Controller.java

package wang.raye.springcloudclient;

import org.springframework.beans.factory.annotation.Autowired;  
import org.springframework.web.bind.annotation.RequestMapping;  
import org.springframework.web.bind.annotation.RestController;

/**
 * feign调用的Controller
 * Created by Raye on 2017/6/26.
 */
@RestController
public class Controller {

    @Autowired
    private HelloService helloService;
    /**
     * 远程通过feign调用另外一个项目的方法
     * @param name
     * @return
     */
    @RequestMapping("hello")
    public String hello(String name){
        return helloService.sayHelloFromRibbon(name);
    }

    /**
     * 使用ribbon方式调用的方法
     * @param name
     * @return
     */
    @RequestMapping("ribbonhello")
    public String sayHello(String name){
        return "hello "+name+" this is feign spring cloud";
    }
}

在Controller中,直接自动注入HelloService就行了,具体实现Spring cloud已经帮我们实现了,只要配置是正确的就行了,同时ribbonhello是被第一个项目远程调用的方法,hello是远程调用第一个项目的接口,最后看看application.yml

application.yml

eureka:  
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
server:  
  port: 8762
spring:  
  application:
    name: service-hi

到此,第二个项目就完成了,最后启动3个项目,访问http://localhost:8762/hello?name=Raye 会返回hello Raye this is ribbon spring cloud,访问http://localhost:8764/hello?name=Raye 会返回hello Raye this is feign spring cloud

结尾

spring cloud最简单的基本使用就介绍完了,本文只是为大家介绍一下什么是spring cloud和spring cloud的基本使用,所以并没有深入介绍,另外附上本项目的代码地址

oschina

github

标签:Springboot, spring cloud
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