《springCloud系列》——Eureka 进行服务治理

2023-07-30 12:26:52

整理一下：

  • @EnableEurekaServer     注册中心
  • @EnableDiscoveryClient  提供服务
  • @EnableFeignClients     消费者（Feign特有的，而且他自带断路器）
  • @EnableHystrix          断路器
  • @EnableHystrixDashboard 开启仪表盘
  • @EnableZuulProxy        开启路由

事先声明，一定要按照我上面的pom写，因为各种版本冲突，哎。真是操蛋 。没必要追求最新的。刚开始能跑起来就行。不多说，看代码，如果有错误，看我另外一篇，springcloud错误集合。

新建一个服务中心：目的是让你的写的服务都注册上面，然后还需要写几个服务，然后还要写几个消费者

----------------------------------------------注册中心------------------------------------------------

erueka  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>eureka</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>eureka</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.1.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>Camden.SR6</spring-cloud.version>

        <jdbc.version>5.1.30</jdbc.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>

    </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>
EurekaApplication.java 启动类
package com.example.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication

@EnableEurekaServer

public class EurekaApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaApplication.class, args);

    }

}

application.yml

server:

   port: 9999

spring:

  application:

     name: eureka-service

 #    eureka server 相关配置

eureka:

   instance:

     hostname: localhost

   client:

     registerWithEureka: false #表示是否将自己注册到Eureka Server上，默认为true

     fetchRegistry: false #表示是否从Eureka Server上获取注册信息，默认为true

     serviceUrl:

       defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka #设置服务注册中心的URL

ok，一个最简单的注册中心就好了

----------------------------------------------注册服务------------------------------------------------

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>eureka-client</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.1.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>Camden.SR6</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>
EurekaClientApplication.java
package com.example.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication

@EnableDiscoveryClient

public class EurekaClientApplication {

    public static void main(String[] args) {

        SpringApplication.run(EurekaClientApplication.class, args);

    }

}


application.yml






server:

   port: 9998

spring:

  application:

     name: eureka-client

eureka:

  client:

    serviceUrl:

      defaultZone: http://localhost:9999/eureka






----------------------------------------------负载均衡ribbon----------------------------------------


将注册服务再复制一份，端口改一下，spring.application.name.eureka-client      这个要一样 这样就配了一个小集群。然后用ribbon来创建消费者，配置一个简单的负载均衡服务


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>springcloudribbon</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>springcloud-ribbon</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.1.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>Camden.SR6</spring-cloud.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-web</artifactId>

        </dependency>

        <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>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-ribbon</artifactId>

        </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>

    <repositories>

        <repository>

            <id>spring-milestones</id>

            <name>Spring Milestones</name>

            <url>https://repo.spring.io/milestone</url>

            <snapshots>

                <enabled>false</enabled>

            </snapshots>

        </repository>

    </repositories>

</project>






SpringcloudRibbonApplication.java






package com.example.demo;

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 SpringcloudRibbonApplication {

    public static void main(String[] args) {

        SpringApplication.run(SpringcloudRibbonApplication.class, args);

    }

    @Bean

    @LoadBalanced

    RestTemplate restTemplate() {

        return new RestTemplate();

    }

}






HelloControler.java






package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

/**

 * Created by lilipo on 2018/5/3.

 */

@RestController

public class HelloControler {

    @Autowired

    HelloService helloService;

    @RequestMapping(value = "/hi")

    public String hi(@RequestParam String name){

        return helloService.hiService(name);

    }

}






HelloService.java






package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.stereotype.Service;

import org.springframework.web.client.RestTemplate;

/**

 * Created by lilipo on 2018/5/3.

 */

@Service

public class HelloService {

    @Autowired

    RestTemplate restTemplate;

    public String hiService(String name) {

        return restTemplate.getForObject("http://eureka-client/hi?name="+name,String.class);

    }

}








如果正确启动的话，你会在浏览器上看到端口轮询出现。就说明负载均衡配置好了。实在是太简单了。参考博客：https://blog.csdn.net/forezp/article/details/69788938


----------------------------------------------服务消费者（Feign）----------------------------------------


Feign是一个声明式的伪Http客户端，它使得写Http客户端变得更简单。使用Feign，只需要创建一个接口并注解。它具有可插拔的注解特性，可使用Feign 注解和JAX-RS注解。Feign支持可插拔的编码器和解码器。Feign默认集成了Ribbon，并和Eureka结合，默认实现了负载均衡的效果。


简而言之：


    

  • Feign 采用的是基于接口的注解
    • 

  • Feign 整合了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>com.example</groupId>

    <artifactId>springcloudfeign</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>springcloud-feign</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.1.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>Camden.SR6</spring-cloud.version>

        <jdbc.version>5.1.30</jdbc.version>

    </properties>

    <dependencies>

        <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.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>






SpringcloudFeignApplication.java （@EnableFeignClients注解开启Feign的功能）






package com.example.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

import org.springframework.cloud.netflix.feign.EnableFeignClients;

@SpringBootApplication

@EnableDiscoveryClient

@EnableFeignClients

public class SpringcloudFeignApplication {

    public static void main(String[] args) {

        SpringApplication.run(SpringcloudFeignApplication.class, args);

    }

}






HiController.java






package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

import org.springframework.web.bind.annotation.RestController;

/**

 * Created by lilipo on 2018/5/3.

 */

@RestController

public class HiController {

    @Autowired

    SchedualServiceHi schedualServiceHi;

    @RequestMapping(value = "/hi",method = RequestMethod.GET)

    public String sayHi(@RequestParam String name){

        return schedualServiceHi.sayHiFromClientOne(name);

    }

}






SchedualServiceHi.java （定义一个feign接口，通过@ FeignClient（“服务名”），来指定调用哪个服务。比如在代码中调用了service-hi服务的“/hi”接口）






package com.example.demo;

import org.springframework.cloud.netflix.feign.FeignClient;

import org.springframework.stereotype.Service;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import org.springframework.web.bind.annotation.RequestParam;

/**

 * Created by lilipo on 2018/5/3.

 */

@FeignClient(value = "eureka-client")

@Service

public interface  SchedualServiceHi {

    @RequestMapping(value = "/hi",method = RequestMethod.GET)

    String sayHiFromClientOne(@RequestParam(value = "name") String name);

}






如果正确启动，那么会实现和ribbon一样的效果。默认有负载均衡的作用，更加简单。


参考博客：https://blog.csdn.net/forezp/article/details/69808079


----------------------------------------------断路器（Hystrix）----------------------------------------


断路器（Hystrix）的作用就是当你的调用服务的时候，注册的服务挂了，这时候会走一个你指定的方法，而不是一直等待或者报错。分别从ribbon和Feign两种情况做演示


只是改造而已，在ribbon的项目上增加下面这个依赖




<dependency>

    <groupId>org.springframework.cloud</groupId>

    <artifactId>spring-cloud-starter-hystrix</artifactId>

</dependency>




在启动类上增加@EnableHystrix注解


改造HelloService类，在hiService方法上加上@HystrixCommand注解。该注解对该方法创建了熔断器的功能，并指定了fallbackMethod熔断方法，熔断方法直接返回了一个字符串，字符串为”hi,”+name+”,sorry,error!”，代码如下：






@Service

public class HelloService {

    @Autowired

    RestTemplate restTemplate;

    @HystrixCommand(fallbackMethod = "hiError")

    public String hiService(String name) {

        return restTemplate.getForObject("http://SERVICE-HI/hi?name="+name,String.class);

    }

    public String hiError(String name) {

        return "hi,"+name+",sorry,error!";

    }

}






当 service-hi 工程不可用的时候，service-ribbon调用 service-hi的API接口时，会执行快速失败，直接返回一组字符串，而不是等待响应超时，这很好的控制了容器的线程阻塞。


Feign中使用断路器


Feign是自带断路器的，在D版本的Spring Cloud中，它没有默认打开。需要在配置文件中配置打开它，在配置文件加以下




feign.hystrix.enabled=true




基于service-feign工程进行改造，只需要在FeignClient的SchedualServiceHi接口的注解中加上fallback的指定类就行了：






@FeignClient(value = "service-hi",fallback = SchedualServiceHiHystric.class)

public interface SchedualServiceHi {

    @RequestMapping(value = "/hi",method = RequestMethod.GET)

    String sayHiFromClientOne(@RequestParam(value = "name") String name);

}






SchedualServiceHiHystric需要实现SchedualServiceHi 接口，并注入到Ioc容器中，代码如下：






@Component

public class SchedualServiceHiHystric implements SchedualServiceHi {

    @Override

    public String sayHiFromClientOne(String name) {

        return "sorry "+name;

    }

}






------------------------Hystrix Dashboard (断路器：Hystrix 仪表盘)-------------------------------------


基于service-ribbon 改造


在pom中增加依赖






<dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-actuator</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-hystrix</artifactId>

        </dependency>






在主程序启动类中加入@EnableHystrixDashboard注解，开启hystrixDashboard：


ok，访问：http://192.168.1.28:9996/hystrix  端口号是你这个ribbon项目的端口号  会出现一个熊猫界面


第一个框填上http://localhost:9996/hystrix.stream   第二个Title  随便填。自定义名字 然后点击下面的按钮会出现另外一个界面


基于service-ribbon 改造             （和ribbon的差不多，但是有坑，依赖问题，需要注意一下。 ）


添加依赖






<dependency>

            <groupId>org.springframework.boot</groupId>

            <artifactId>spring-boot-starter-actuator</artifactId>

            <version>1.5.10.RELEASE</version>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>

            <version>RELEASE</version>

        </dependency>






在主程序启动类中加入@EnableHystrixDashboard注解，开启hystrixDashboard：


参考博客：https://blog.csdn.net/forezp/article/details/69934399#commentsedit


------------------------------------------路由网关(zuul)-----------------------------------------------


新建一个zuul网关项目


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>springcloudzuul</artifactId>

    <version>0.0.1-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>springcloud-zuul</name>

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

    <parent>

        <groupId>org.springframework.boot</groupId>

        <artifactId>spring-boot-starter-parent</artifactId>

        <version>1.5.1.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>Camden.SR6</spring-cloud.version>

        <jdbc.version>5.1.30</jdbc.version>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-eureka</artifactId>

        </dependency>

        <dependency>

            <groupId>org.springframework.cloud</groupId>

            <artifactId>spring-cloud-starter-zuul</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>






SpringcloudZuulApplication.java(@EnableZuulProxy注解开启路由)






package com.example.demo;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

import org.springframework.cloud.netflix.zuul.EnableZuulProxy;

@EnableZuulProxy

@EnableEurekaClient

@SpringBootApplication

public class SpringcloudZuulApplication {

    public static void main(String[] args) {

        SpringApplication.run(SpringcloudZuulApplication.class, args);

    }

}






 application.yml






eureka:

  client:

    serviceUrl:

      defaultZone: http://localhost:9999/eureka/

server:

  port: 9994

spring:

  application:

    name: service-zuul

zuul:

  routes:

    api-a:

      path: /api-a/**

      serviceId: service-ribbon

    api-b:

      path: /api-b/**

      serviceId: service-feign








首先指定服务注册中心的地址为http://localhost:9999/eureka/，服务的端口为9994，服务名为service-zuul；以/api-a/ 开头的请求都转发给service-ribbon服务；以/api-b/开头的请求都转发给service-feign服务；


 访问：http://localhost:9994/api-a/hi?name=forezp  和  http://localhost:9994/api-b/hi?name=forezp  看结果

参考博客：https://blog.csdn.net/forezp/article/details/69939114
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