hystrix基础操作

1基础demo

完成父模块
完成eureka子模块
完成服务提供者子模块
完成服务消费者子模块

1.完成父模块

新建springboot项目，删除src文件夹

导入maven依赖

<properties>
     <java.version>1.8</java.version>
     <spring.cloud-version>Hoxton.SR3</spring.cloud-version>
</properties>
<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>
    <dependencies>
        <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>

2.完成eureka子模块

新建子模块eureka

导入maven依赖

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

编写application.yml配置文件

server:
  port: 7001
spring:
  application:
    name: cs-eureka
eureka:
  instance:
    # 地址 通常是域名
    hostname: localhost
  client:
    service-url: # 客户端与EurekaServer的交互地址，如果是集群，需要多个地址
      defaultZone: http://localhost:7001/eureka/
    register-with-eureka: false # 是不是将自己注册进eureka 默认 true
    fetch-registry: false # 自己就是服务，不需要从eurekaServer获取服务信息，默认true

编写主启动类

@SpringBootApplication
@EnableEurekaServer //开启服务
public class EurekaApplication {
    public static void main(String[] args) {
        SpringApplication.run(EurekaApplication.class, args);
    }
}

3.完成服务提供者子模块

新建子模块provider-hystrix

导入maven依赖

<dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
    </dependencies>

编写application配置文件

spring:
  application:
    name: provider-hystrix
server:
  port: 8001
eureka:
  client:
    # eureka服务端的路劲
    service-url:
      defaultZone: http://localhost:7001/eureka/
    # 如果不想将改服务注册进注册中心，一定要写成false
    register-with-eureka: true
    fetch-registry: true

编写主启动类

@SpringBootApplication
@EnableEurekaClient
@EnableHystrix
public class HystrixApplication {
    public static void main(String[] args) {
        SpringApplication.run(HystrixApplication.class,args);
    }
}

编写HystrixController.java

降级的方法写在提供者或消费者中都可以，我写到消费者中

@RestController
@RequestMapping("/provider")
public class HystrixController {

    @GetMapping("/hystrix/ok")
    public String providerHystrixOk(){
        return Thread.currentThread().getName() + "providerHystrixOk";
    }

    @GetMapping("/hystrix/timeout")
    public String providerHystrixTimeOut(){
        int time=3;
        //休眠3秒
        try {
            TimeUnit.SECONDS.sleep(time);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        return Thread.currentThread().getName() + "providerHystrixTimeOut,耗时" + time;
    }
}

3.完成服务消费者子模块

导入maven依赖

<dependencies>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>
</dependencies>

编写application.yml文件

server:
  port: 9001
eureka:
  client:
    # eureka服务端的路径，这个就是eureka模块设置的地址
    service-url:
      defaultZone: http://localhost:7001/eureka/
    # 是不是将自己注册进eureka 默认 true，所以这里可以省略不写
    register-with-eureka: true
ribbon:
  ReadTimeout: 5000  #处理请求的超时时间，默认5秒
  ConnectTimeout: 5000 #连接建立的超时时间，默认5秒
feign:
  hystrix:
    enabled: true

编写主启动类

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients
@EnableHystrix
public class ConsumerHystrixApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerHystrixApplication.class,args);
    }
}

ProviderHystrixService.java

@FeignClient(value = "PROVIDER-HYSTRIX")//value是provide注册到eaurke的名字
@Service
public interface ProviderHystrixService {

    @GetMapping("/provider/hystrix/ok")
    String providerHystrixOk();

    @GetMapping("/provider/hystrix/timeout")
    String providerHystrixTimeOut();
}

ConsumerHystrixController.java

@RestController
@RequestMapping("/consumer")
public class ConsumerHystrixController {

    private final ProviderHystrixService providerHystrixService;

    public ConsumerHystrixController(ProviderHystrixService providerHystrixService) {
        this.providerHystrixService = providerHystrixService;
    }

    @GetMapping("/hystrix/ok")
    public String consumerHystrixTimeOk(){
        return providerHystrixService.providerHystrixOk();
    }

/*
fallbackMethod:降级的方法名
name="execution.isolation.thread.timeoutInMilliseconds"熔断的规则
我选的是响应超时时间 value="2000" 2秒
* */

@GetMapping("/hystrix/timeout") 
@HystrixCommand(fallbackMethod = "providerHystrixTimeOutHandler",commandProperties = { 
     @HystrixProperty(name="execution.isolation.thread.timeoutInMilliseconds",value = "2000") 
})

   public String consumerHystrixTimeOut(){ 
       return providerHystrixService.providerHystrixTimeOut(); 
   } 
    //降级的方法
    public String providerHystrixTimeOutHandler(){
        return "哎呀，出错了，服务器丢失";
    }
}

启动eureka

启动provider-hystrix

启动consumer-hystrix

运行截图：

访问正常的方法

访问超时的方法（规则在2s内有响应，程序休眠3秒）

2.基础demo优化

每一个方法都需要有降级一个的方法

解决：使用全局服务降级的方法

修改ConsumerHystrixController.java

@RestController
@RequestMapping("/consumer")
@DefaultProperties(defaultFallback = "global_FallbackMethod")
public class ConsumerHystrixController {

    private final ProviderHystrixService providerHystrixService;

    public ConsumerHystrixController(ProviderHystrixService providerHystrixService) {
        this.providerHystrixService = providerHystrixService;
    }

    @GetMapping("/hystrix/ok")
    public String consumerHystrixTimeOk(){
        return providerHystrixService.providerHystrixOk();
    }

    @GetMapping("/hystrix/timeout")
    @HystrixCommand
    public String consumerHystrixTimeOut(){
        //模拟异常
        int a=10/0;
        return providerHystrixService.providerHystrixTimeOut();
    }
    public String global_FallbackMethod(){
        return "Global异常处理信息，请稍后重试";
    }
}

运行截图:

兜底的方法写到controller中了，耦合了，能不能分离处理

我们采用了OpenFeign实现负载均衡，我们在调用Controller层方法的时候都是去到对应的Service层方法，找到要调用服务的服务名然后去实现调用的，所以我们可以在声明一个类去继承service接口，然后这个类专门对service里面的方法实现Fallback。而且OpenFeign加在Service接口上的注解@FeignClient提供了对Fallback的支持

解决：使用通配服务降级有两种方式

fallbackFactory和fallback

区别在于：fallbackFactory除了可以降级hystrix的异常，其他异常也可以，fallback不行

使用fallback：

新建ProviderHystrixServiceFallBack.java

1.继承ProviderHystrixService接口

2.注意添加@Compoent注解

@Component
public class ProviderHystrixServiceFallback implements FallbackFactory<ProviderHystrixService> {
    private final String MSG="系统异常，正在拿程序员小哥祭天";

    @Override
    public ProviderHystrixService create(Throwable throwable) {
        return new ProviderHystrixService() {
            @Override
            public String providerHystrixOk() {
                return throwable.getMessage() + MSG;
            }

            @Override
            public String providerHystrixTimeOut() {
                return MSG;
            }
        };
    }
}

修改ProviderHystrixService.java

@FeignClient(value = "PROVIDER-HYSTRIX", fallback = ProviderHystrixServiceFallback.class)
@Service
public interface ProviderHystrixService {

    @GetMapping("/provider/hystrix/ok")
    String providerHystrixOk();

    @GetMapping("/provider/hystrix/timeout")
    String providerHystrixTimeOut();

}

修改ConsumerHystrixController.java

@RestController
@RequestMapping("/consumer")
//@DefaultProperties(defaultFallback = "global_FallbackMethod")
public class ConsumerHystrixController {

    private final ProviderHystrixService providerHystrixService;

    public ConsumerHystrixController(ProviderHystrixService providerHystrixService) {
        this.providerHystrixService = providerHystrixService;
    }

    @GetMapping("/hystrix/ok")
    public String consumerHystrixTimeOk(){
        //模拟异常
        int a=10/0;
        return providerHystrixService.providerHystrixOk();
    }

    @GetMapping("/hystrix/timeout")
    public String consumerHystrixTimeOut(){
        return providerHystrixService.providerHystrixTimeOut();
    }
}