spring cloud微服务分布式云架构--hystrix的使用-白红宇

hystrix主要作用在服务消费者，进行应用的保护，当请求的服务请求超时时，做出相应的处理，避免客户端一直进行请求等待，避免在高并发的情况出现服务器死机（请求过多，内存不足）

接下来的通过一个案例对hystrix的使用进行说明，案例完成的功能：

服务消费者根据Id调用服务提供者的接口，获取User表单的对应的记录，若请求超时则返回id为-1的User记录

一、基于Ribbon


          
     
      org.springframework.boot
           
     
      spring-boot-starter-parent
           
     
      1.5.2.RELEASE
           
      
       
     
        
     
      UTF-8
         
     
      1.8
         
     
      1.2.0
         
     
      5.1.39
     
     
        
             
      
       org.springframework.boot
              
      
       spring-boot-starter-web
          
         
             
      
       org.springframework.cloud
              
      
       spring-cloud-starter-eureka
              
      
       1.3.5.RELEASE
          
         
             
      
       org.springframework.cloud
              
      
       spring-cloud-starter-hystrix
              
      
       1.3.5.RELEASE

2、application.yml

server:  port: 8089spring:  application:    name: customer-usereureka:  client:     serviceUrl:       defaultZone: http://user:zj123@localhost:8761/eureka  instance:    prefer-ip-address: true    instance-id: ${spring.application.name}:${spring.cloud.client.ipAddress}:${spring.application.instance_id:${server.port}}provider-user:   ribbon:     NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule

3、Controller调用类

import org.springframework.beans.factory.annotation.Autowired;import org.springframework.http.MediaType;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController;import org.springframework.web.client.RestTemplate; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;import com.zhuojing.bean.User; @RestControllerpublic class UserController {     @Autowired    private RestTemplate restTemplate;            @GetMapping(value="/simple/{id}",produces=MediaType.APPLICATION_JSON_VALUE+";charset=utf-8")    @HystrixCommand(fallbackMethod = "findByIdFallback")    public User findUserById(@PathVariable Long id){        //服务提供者地址 PROVIDER-USER        return this.restTemplate.getForObject("http://PROVIDER-USER/simple/"+id, User.class);    }    /**     * 断路器模式，当请求的消费者provider-user超时的情况下，就会直接调用此方法，此方法的参数和返回类型必须和findUserById方法一致，请求超时时间为1秒     * @param id     * @return     */    public User findByIdFallback(Long id){        User user = new User();        user.setId(0L);        return user;    }    }

hystrix的默认的超时时间为1秒，若自定hystrix超时时间有一下两种方式

a、@HystrixCommand注解配置

@HystrixCommand(fallbackMethod = "findByIdFallback",commandProperties = {     @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")})

b、在application.yml配置

hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 5000

4、启动类

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;import org.springframework.cloud.client.loadbalancer.LoadBalanced;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.cloud.netflix.ribbon.RibbonClient;import org.springframework.context.annotation.Bean;import org.springframework.context.annotation.ComponentScan;import org.springframework.context.annotation.FilterType;import org.springframework.web.client.RestTemplate; @SpringBootApplication@EnableEurekaClient@EnableCircuitBreakerpublic class AppCusRibbonPropertiesTest {     @Bean    @LoadBalanced    public RestTemplate restTemplate(){        return new RestTemplate();    }    public static void main(String[] args) {        SpringApplication.run(AppCusRibbonPropertiesTest.class, args);    }}

二、dashboard的使用

1、pom.xml


          
     
      org.springframework.boot
           
     
      spring-boot-starter-parent
           
     
      1.5.2.RELEASE
           
      
       
      
            
                 
      
       org.springframework.cloud
                  
      
       spring-cloud-starter-hystrix-dashboard
                  
      
       1.3.5.RELEASE

2、application.yml

server:

port: 8030

3、启动类

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard; @EnableHystrixDashboard@SpringBootApplicationpublic class DashboardApplication {  public static void main(String[] args) {    SpringApplication.run(DashboardApplication.class, args);  }}

启动后访问： /localhost:8030/hystrix 进入首页，在地址栏上输入 /localhost:8089/hystrix.stream（hystrix.stream）进行监控，在使用了hystrix的服务调用后才有数据。

三、Turbine的使用，Turbine是对微服务集群的监听

1、pom.xml


          
     
      org.springframework.boot
           
     
      spring-boot-starter-parent
           
     
      1.5.2.RELEASE
           
      
       
      
        
             
      
       org.springframework.cloud
              
      
       spring-cloud-starter-turbine
              
      
       1.3.5.RELEASE

2、application.yml

server:  port: 8031spring:  application:    name: microservice-hystrix-turbineeureka:  client:    serviceUrl:      defaultZone: http://user:zj123@localhost:8761/eureka  instance:    prefer-ip-address: trueturbine:  aggregator:    clusterConfig: default  #默认defualt，只有一个服务时候可以写服务名称的大写CUSTOMER-USER  appConfig: customer-user  clusterNameExpression: "'default'"

3、启动类

import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.turbine.EnableTurbine; @EnableTurbine@SpringBootApplicationpublic class TurbineApplication {  public static void main(String[] args) {    SpringApplication.run(TurbineApplication.class, args);  }}

hystrix 主页面中将localhost:8031/turbine.stream?cluster=CUSTOMER-USER填入，便可进行数据的图像化。