springcloud使用ribbon+RestTemplate+Hystrix实现熔断机制

蔚落 2022-01-23 09:47 296阅读 0赞

### **本次的实现承接上篇springcloud使用ribbon+RestTemplate实现负载均衡的基础上进行的** ###

一 项目总结构图

![20190603150917715.jpg][]

二 本次实现eureka-ribbon 中的熔断机制，进行操作，其余三个项目就不进行展示了

二(1)  eureka-ribbon结构图

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDQ5OTM5NA_size_16_color_FFFFFF_t_70][]

二(3)   pim.xml文件

这三个依赖就是需要接入的，用来进行熔断操作

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        <version>2.0.2.RELEASE</version>
    </dependency>
    
    
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
        <version>2.1.3.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
        <version>1.4.6.RELEASE</version>
    </dependency>

<?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>
        <parent>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-parent</artifactId>
            <version>2.1.5.RELEASE</version>
            <relativePath/> 
        </parent>
        <groupId>com.dr</groupId>
        <artifactId>eureka-ribbon</artifactId>
        <version>0.0.1-SNAPSHOT</version>
        <name>eureka-ribbon</name>
        <description>Demo project for Spring Boot</description>
    
        <properties>
            <java.version>1.8</java.version>
            <spring-cloud.version>Greenwich.SR1</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-netflix-eureka-client</artifactId>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-netflix-ribbon</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-netflix-hystrix</artifactId>
                <version>2.0.2.RELEASE</version>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
                <version>2.1.3.RELEASE</version>
            </dependency>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
                <version>1.4.6.RELEASE</version>
            </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>

二(4)  application.properties文件

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

二(5) EurekaRibbonApplication 启动文件

这两个注解就是启动熔断机制

@EnableHystrix//开启断路器功能  
@EnableHystrixDashboard

package com.dr;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.netflix.hystrix.EnableHystrix;
    import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
    
    @SpringBootApplication
    @EnableDiscoveryClient
    @EnableHystrix//开启断路器功能
    @EnableHystrixDashboard
    public class EurekaRibbonApplication {
    
        public static void main(String[] args) {
            SpringApplication.run(EurekaRibbonApplication.class, args);
        }
    
    }

二(6)  ribbonService 类

package com.dr.ribbonService;
    
    import org.springframework.cloud.client.loadbalancer.LoadBalanced;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.client.RestTemplate;
    
    @Configuration
    public class RibbonService {
    
        /**
         * Configuration  代表这是一个RestTemplate配置
         *
         * Bean  应用在方法上，用来将方法返回值设为为bean
         *
         * LoadBalanced  实现负载均衡，一定要加
         *
         * @return
         */
    
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate(){
            return new RestTemplate();
        }
    }

二(7)  RibbonRestTemplate类

package com.dr.ribbonController;
    
    
    import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
    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;
    
    @RestController
    public class RibbonRestTemplate {
    
    
        @Autowired
        RestTemplate restTemplate;
    
        //使用断路器
        @HystrixCommand(fallbackMethod = "errorMethod")
        @RequestMapping("/hi")
        public String sayClient(){
            return  restTemplate.getForObject("http://service-client/hi/",String.class);
        }
    
    
        //当服务不可用时调用此方法返回
        public String errorMethod(){
            return "This is a error page";
        }
    
    
    }

二(8)  浏览器测试结果  正常状态下的

![20190603153938430.jpg][]

![20190603153956843.jpg][]

关掉其中一个服务提供者之后，多次刷新页面

![20190603154048442.jpg][]

这就是熔断机制，一旦服务停止，就会到你所指定的方法中，有不对的地方，请各位大佬多多指教

[20190603150917715.jpg]: /images/20220123/a77c4b7f435a4c1f834f0ae2c4e7561d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80NDQ5OTM5NA_size_16_color_FFFFFF_t_70]: /images/20220123/a75684d260404ae08b1c709a0db49531.png
[20190603153938430.jpg]: /images/20220123/8718c8e4bea7460d9b9a518df4232109.png
[20190603153956843.jpg]: /images/20220123/7f5bbdca65a549c28293af5d5edf6ac9.png
[20190603154048442.jpg]: /images/20220123/fc8cab1800134e339aff1e0ca701c931.png