spring cloud 项目搭建：4、Hystrix服务熔断、降级

缺乏、安全感 2023-10-08 12:51 34阅读 0赞

#### 文章目录 ####

*  写在前面
 *   *  1、Hystrix介绍
     *  2、Hystrix使用
     *   *  2.1、服务熔断
         *   *  2.1.1、pom.xml
             *  2.1.2、application.yml
             *  2.1.3、DeptController使用熔断后备选方法
             *  2.1.4、DeptProviderApplication8001\_hystrix启动类上添加对熔断的支持
         *  2.2、服务降级
     *  3、其他的一些配置
     *  4、Hystrix监控页面

## 写在前面 ##

*  [ spring cloud 项目搭建 ：1、eureka 服务治理][spring cloud _ _1_eureka]: https://blog.csdn.net/a\_\_int\_\_/article/details/116791386
 *  [ spring cloud 项目搭建 ：2、ribbon客户端负载均衡][spring cloud _ _2_ribbon]: https://blog.csdn.net/a\_\_int\_\_/article/details/116797413
 *  [ spring cloud 项目搭建 ：3、Feign接口负载均衡][spring cloud _ _3_Feign]: https://blog.csdn.net/a\_\_int\_\_/article/details/117438047
 *  [ spring cloud 项目搭建 ：5、zuul 网关][spring cloud _ _5_zuul]:https://blog.csdn.net/a\_\_int\_\_/article/details/117568053

### 1、Hystrix介绍 ###

在微服务中，如果某个资源响应时间过长或者崩了，就容易引起雪崩效应。Hystrix去及时断开、反馈这些有问题的服务。

### 2、Hystrix使用 ###

#### 2.1、服务熔断 ####

新建模块springcloud-provider-dept-hystrix-8001  
![在这里插入图片描述][20210601152041575.png]  
hystrix的依赖

<dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-hystrix</artifactId>
                <version>1.4.6.RELEASE</version>
            </dependency>

下面是模块目录结构，有变化的主要红框框起来的文件，其他的内容和springcloud-provider-dept-8001模块中一模一样  
![在这里插入图片描述][20210601154642510.png]

##### 2.1.1、pom.xml #####

pom.xml完整内容

<?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">
        <parent>
            <artifactId>clouddemo</artifactId>
            <groupId>org.example</groupId>
            <version>1.0-SNAPSHOT</version>
        </parent>
        <modelVersion>4.0.0</modelVersion>
    
        <artifactId>springcloud-provider-dept-hystrix-8001</artifactId>
    
        <dependencies>
            <dependency>
                <groupId>junit</groupId>
                <artifactId>junit</artifactId>
            </dependency>
            <dependency>
                <groupId>mysql</groupId>
                <artifactId>mysql-connector-java</artifactId>
            </dependency>
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>druid</artifactId>
            </dependency>
            <dependency>
                <groupId>ch.qos.logback</groupId>
                <artifactId>logback-core</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.mybatis.spring.boot</groupId>
                <artifactId>mybatis-spring-boot-starter</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-jetty</artifactId>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-devtools</artifactId>
            </dependency>
    
            
            <dependency>
                <groupId>org.example</groupId>
                <artifactId>springcloud-api</artifactId>
                <version>1.0-SNAPSHOT</version>
                <scope>compile</scope>
            </dependency>
    
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-eureka</artifactId>
                <version>1.4.6.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-starter-hystrix</artifactId>
                <version>1.4.6.RELEASE</version>
            </dependency>
            
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-starter-actuator</artifactId>
            </dependency>
        </dependencies>
    </project>

##### 2.1.2、application.yml #####

和springcloud-provider-dept-8001模块里的配置一模一样

server.port: 8001
    mybatis:
    #  type-aliases-package: org.example.bean
    #  config-location: classpath:mybatis-config.xml
      mapper-locations: classpath:mapper/*.xml
    
    spring:
      application:
        name: springcloud-provider-dept
      # 不使用mybatis的默认数据源，
      datasource:
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: org.gjt.mm.mysql.Driver
        url: jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8
        username: root
        password: root
    
    # 开启mybatis sql语句打印
    logging.level.org.exampl.dao: debug
    
    # eureka配置
    eureka:
      client:
        service-url:
          defaultZone: http://127.0.0.1:7001/eureka/,http://127.0.0.2:7002/eureka/,http://127.0.0.3:7003/eureka/
      instance:
        # 修改eureka网页上的默认描述信息
        instance-id: provider-dept-hystrix:8001
    
    info:
      app.name: 我的微服务1-hystrix
      company.name: yayaya

##### 2.1.3、DeptController使用熔断后备选方法 #####

![在这里插入图片描述][20210601154347561.png]

import com.demo.bean.Dept;
    import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
    import org.example.service.DeptService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    @RequestMapping("/dept")
    public class DeptController {
        
        @Autowired
        private DeptService deptService;
    
        // fallbackMethod失败后调用方法
        @HystrixCommand(fallbackMethod = "hystrix_queryById")
        @RequestMapping("/get/{id}")
        public Dept queryById(@PathVariable("id") Long id){
        
            Dept dept = deptService.queryById(id);
            if(dept == null ) {
        
                throw new RuntimeException("id: "+ id + ",不存在");
            }
            return dept;
        }
    
        // 备选方法
        public Dept hystrix_queryById(@PathVariable("id") Long id){
        
            return new Dept().setDeptno(id).setDname("id: "+ id + ",的用户不存在--------@hystrix");
        }
    }

##### 2.1.4、DeptProviderApplication8001\_hystrix启动类上添加对熔断的支持 #####

> @EnableCircuitBreaker // 添加对熔断的支持

import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    
    @SpringBootApplication
    @EnableEurekaClient
    @EnableDiscoveryClient
    @EnableCircuitBreaker     // 添加对熔断的支持
    public class DeptProviderApplication8001_hystrix {
        
        public static void main(String[] args) {
        
            SpringApplication.run(DeptProviderApplication8001_hystrix.class,args);
        }
    }

#### 2.2、服务降级 ####

在springcloud-api里面新增一个服务降级的类DeptClientServiceFallback

import com.demo.bean.Dept;
    import feign.hystrix.FallbackFactory;
    import org.springframework.stereotype.Component;
    
    import java.util.List;
    
    // 服务降级
    @Component
    public class DeptClientServiceFallback implements FallbackFactory {
        
        @Override
        public DeptClientService create(Throwable throwable) {
        
            return new DeptClientService(){
        
                @Override
                public Dept get(Long id) {
        
                    return new Dept().setDeptno(id).setDname("没有对应的信息-----降级信息：这个服务已经被关闭");
                }
    
                @Override
                public List<Dept> getList() {
        
                    return null;
                }
    
                @Override
                public Boolean add(Dept dept) {
        
                    return null;
                }
            };
        }
    }

在DeptClientService中上面这个实现了用上

> fallbackFactory = DeptClientServiceFallback.class

![在这里插入图片描述][20210601171015332.png]  
启动下面几个模块测试  
![在这里插入图片描述][2021060117112647.png]

### 3、其他的一些配置 ###

prefer-ip-address: true //显示IP  
![在这里插入图片描述][2021060116552626.png]  
![在这里插入图片描述][20210601165608786.png]

### 4、Hystrix监控页面 ###

Hystrix监控页面监控页面可以查看服务的熔断情况、流量等信息

步骤：  
1、新建一个模块，启动监控页面  
![在这里插入图片描述][20210604170535656.png]  
新模块需要的依赖  
![在这里插入图片描述][20210604170621825.png]  
application.yml  
![20210604170706186.png][]  
启动类  
![在这里插入图片描述][20210604170805588.png]  
2、第二步、在服务提供者里面加入相关依赖  
![在这里插入图片描述][20210604170933840.png]  
在它的启动类里面加入一个bean  
![在这里插入图片描述][20210604171035587.png]

访问监控页面：

![在这里插入图片描述][20210604171157548.png]  
![在这里插入图片描述][20210604171211679.png]  
发起一个请求查看监控页面的变化  
![在这里插入图片描述][20210604171247797.png]  
![在这里插入图片描述][20210604171301425.png]

[spring cloud _ _1_eureka]: https://blog.csdn.net/a__int__/article/details/116791386
[spring cloud _ _2_ribbon]: https://blog.csdn.net/a__int__/article/details/116797413
[spring cloud _ _3_Feign]: https://blog.csdn.net/a__int__/article/details/117438047
[spring cloud _ _5_zuul]: https://blog.csdn.net/a__int__/article/details/117568053
[20210601152041575.png]: https://img-blog.csdnimg.cn/20210601152041575.png
[20210601154642510.png]: https://img-blog.csdnimg.cn/20210601154642510.png
[20210601154347561.png]: https://img-blog.csdnimg.cn/20210601154347561.png
[20210601171015332.png]: https://img-blog.csdnimg.cn/20210601171015332.png
[2021060117112647.png]: https://img-blog.csdnimg.cn/2021060117112647.png
[2021060116552626.png]: https://img-blog.csdnimg.cn/2021060116552626.png
[20210601165608786.png]: https://img-blog.csdnimg.cn/20210601165608786.png
[20210604170535656.png]: https://img-blog.csdnimg.cn/20210604170535656.png
[20210604170621825.png]: https://img-blog.csdnimg.cn/20210604170621825.png
[20210604170706186.png]: https://img-blog.csdnimg.cn/20210604170706186.png
[20210604170805588.png]: https://img-blog.csdnimg.cn/20210604170805588.png
[20210604170933840.png]: https://img-blog.csdnimg.cn/20210604170933840.png
[20210604171035587.png]: https://img-blog.csdnimg.cn/20210604171035587.png
[20210604171157548.png]: https://img-blog.csdnimg.cn/20210604171157548.png
[20210604171211679.png]: https://img-blog.csdnimg.cn/20210604171211679.png
[20210604171247797.png]: https://img-blog.csdnimg.cn/20210604171247797.png
[20210604171301425.png]: https://img-blog.csdnimg.cn/20210604171301425.png