springCloud-服务治理-Hystrix

Hystrix作为一款服务治理框架，被使用的很多，但是官方已经不再维护，取而代之的是Resilience4j框架。

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所以本文简单介绍Hystrix的使用，把重点放在下一篇的Resilience4j的讲解上。

案例

1、Eureka服务注册和发现
2、一个服务提供者waiter-service
3、基于Feign实现的调用者customer-service，调用waiter-service的方法，服务治理在customer-service上使用。
4、Hsytrix dashboard 用于监控服务调用情况。

步骤

启动watier-service,并注册uereka

1、启动文件：

import com.fasterxml.jackson.datatype.hibernate5.Hibernate5Module;

import java.util.TimeZone;

@SpringBootApplication
@EnableJpaRepositories
@EnableCaching
@EnableDiscoveryClient
public class WaiterServiceApplication implements WebMvcConfigurer {

    public static void main(String[] args) {
        SpringApplication.run(WaiterServiceApplication.class, args);
    }
}

2、POM文件

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.4.RELEASE
         
    
    jane.spring.com
    waiter-service
    0.0.1-SNAPSHOT
    waiter-service
    Demo project for Spring Boot

    
        1.8
        Greenwich.SR1
    

    
        
            org.springframework.boot
            spring-boot-starter-cache
        
        
            org.springframework.boot
            spring-boot-starter-data-jpa
        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        

        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
        

        
            io.micrometer
            micrometer-registry-prometheus
        

        
            org.joda
            joda-money
            1.0.1
        
        
            org.jadira.usertype
            usertype.core
            6.0.1.GA
        
        
        
            com.fasterxml.jackson.datatype
            jackson-datatype-hibernate5
            2.9.8
        

        
            org.apache.commons
            commons-lang3
        

        
            com.h3database
            h3
            runtime
        
        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.cloud
                spring-cloud-dependencies
                ${spring-cloud.version}
                pom
                import
            
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

3、配置文件：

spring.application.name=waiter-service

management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always

info.app.author=DigitalSonic
info.app.encoding=@project.build.sourceEncoding@

eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka/

server.port=8091

4、方法文件

import java.util.ArrayList;
import java.util.List;

@RestController
@RequestMapping("/coffee")
@Slf4j
public class CoffeeController {
    @Autowired
    private CoffeeService coffeeService;

    @GetMapping("/{id}")
    public Coffee getById(@PathVariable Long id) {
        Coffee coffee = coffeeService.getCoffee(id);
        log.info("Coffee {}:", coffee);
        return coffee;
    }
}

5、启动后Eureka效果

启动customer-service服务

1、启动文件

import lombok.extern.slf4j.Slf4j;

import java.util.concurrent.TimeUnit;

@SpringBootApplication
@Slf4j
@EnableDiscoveryClient
@EnableFeignClients
@EnableCircuitBreaker
public class CustomerServiceApplication {

    public static void main(String[] args) {
        SpringApplication.run(CustomerServiceApplication.class, args);
    }

    @Bean
    public CloseableHttpClient httpClient() {
        return HttpClients.custom()
                .setConnectionTimeToLive(30, TimeUnit.SECONDS)
                .evictIdleConnections(30, TimeUnit.SECONDS)
                .setMaxConnTotal(200)
                .setMaxConnPerRoute(20)
                .disableAutomaticRetries()
                .setKeepAliveStrategy(new CustomConnectionKeepAliveStrategy())
                .build();
    }
}

2、pom文件

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.4.RELEASE
         
    
    jane.spring.com
    customer-service
    0.0.1-SNAPSHOT
    customer-service
    Demo project for Spring Boot

    
        1.8
        Greenwich.SR1
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-eureka-client
            2.1.1.RELEASE
        
        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
            io.github.openfeign
            feign-httpclient
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-hystrix
        

        
            org.joda
            joda-money
            1.0.1
        

        
            org.apache.commons
            commons-lang3
        

        
            org.apache.httpcomponents
            httpclient
            4.5.7
        

        
            org.projectlombok
            lombok
            true
        
        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.cloud
                spring-cloud-dependencies
                ${spring-cloud.version}
                pom
                import
            
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

3、配置文件

server.port=8090
spring.application.name=customer-service

management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always

feign.client.config.default.connect-timeout=500
feign.client.config.default.read-timeout=500
feign.hystrix.enabled=true
eureka.client.service-url.defaultZone=http://127.0.0.1:8761/eureka/

4、控制器url

import java.util.Arrays;
import java.util.List;

@RestController
@RequestMapping("/customer")
@Slf4j
public class CustomerController {
    @Autowired
    private CoffeeService coffeeService;

    @GetMapping("/coffee")
    @HystrixCommand(fallbackMethod = "fallbackMethod")
    public Coffee getCoffee() {
        Coffee list = coffeeService.getById(1l);
        log.info("Read coffee: {} coffee", list);
        return list;
    }

    public Coffee fallbackMethod() {
        log.warn("Fallback ......");
        return null;
    }
}

5、fegin客户端

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.List;

@FeignClient(name = "waiter-service", contextId = "coffee",
        qualifier = "coffeeService", path="/coffee",
        fallback = FallbackCoffeeService.class)
// 如果用了Fallback，不要在接口上加@RequestMapping，path可以用在这里
public interface CoffeeService {
    @GetMapping("/{id}")
    Coffee getById(@PathVariable Long id);
}

6、运行后，eureka效果

启动Hystrix-dashboard

1、启动文件：

import com.netflix.hystrix.contrib.metrics.eventstream.HystrixMetricsStreamServlet;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableHystrixDashboard
public class HystrixDashboardDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(HystrixDashboardDemoApplication.class, args);
    }

    @Bean
    public ServletRegistrationBean ServletRegistrationBeangetServlet() {

        HystrixMetricsStreamServlet streamServlet =new HystrixMetricsStreamServlet();

        ServletRegistrationBean registrationBean =new ServletRegistrationBean(streamServlet);

        registrationBean.setLoadOnStartup(1);

        registrationBean.addUrlMappings("/hystrix.stream");

        registrationBean.setName("HystrixMetricsStreamServlet");

        return registrationBean;

    }

}

2、配置文件

server.port=9090

3、pom文件

    4.0.0
    
        org.springframework.boot
        spring-boot-starter-parent
        2.1.4.RELEASE
         
    
    jane.spring.cloud
    hystrix-dashboard-demo
    0.0.1-SNAPSHOT
    hystrix-dashboard-demo
    Demo project for Spring Boot

    
        1.8
        Greenwich.SR1
    

    
        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-hystrix-dashboard
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    

    
        
            
                org.springframework.cloud
                spring-cloud-dependencies
                ${spring-cloud.version}
                pom
                import
            
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

3、启动后效果如下

4、将地址输入上述文本框，并点击Monitor Stream按钮

http://127.0.0.1:8090/actuator/hystrix.stream

5、调用如下请求：

6、查看Hystrix-dashboard 效果

7、停止waiter-service服务，再次调用，可以看到错误