SpringCloud系列第06节之断路器Hystrix

package com.jadyer.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

//创建服务注册中心
@EnableEurekaServer
@SpringBootApplication
public class ServiceDiscoveryBootStrap {
    public static void main(String[] args) {
        SpringApplication.run(ServiceDiscoveryBootStrap.class, args);
    }
}

package com.jadyer.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

/**
 * 通过 @EnableEurekaClient 注解，为服务提供方赋予注册和发现服务的能力
 * ------------------------------------------------------------------------------------------------------------------
 * 也可以使用org.springframework.cloud.client.discovery.@EnableDiscoveryClient注解
 * 详见以下两篇文章的介绍
 * http://cloud.spring.io/spring-cloud-static/Camden.SR3/#_registering_with_eureka
 * https://spring.io/blog/2015/01/20/microservice-registration-and-discovery-with-spring-cloud-and-netflix-s-eureka
 * ------------------------------------------------------------------------------------------------------------------
 * Created by 玄玉<https://jadyer.cn/> on 2017/1/9 16:00.
 */
@EnableEurekaClient
@SpringBootApplication
public class ServiceServerBootStarp {
    public static void main(String[] args) {
        SpringApplication.run(ServiceServerBootStarp.class, args);
    }
}

package com.jadyer.demo;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;

/**
 * 服务提供方暴露的数学运算服务
 * Created by 玄玉<https://jadyer.cn/> on 2017/1/9 16:00.
 */
@RestController
public class CalculatorController {
    private final Logger logger = LoggerFactory.getLogger(getClass());
    @Resource
    private DiscoveryClient client;

    @RequestMapping("/add")
    public int add(int a, int b){
        //加运算
        int result = a + b;
        //输出服务信息
        ServiceInstance instance = client.getLocalServiceInstance();
        logger.info("uri={}，serviceId={}，result={}", instance.getUri(), instance.getServiceId(), result);
        //返回结果
        return result;
    }
}

package com.jadyer.demo;
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.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

//@SpringCloudApplication
//开启断路器功能
@EnableCircuitBreaker
@EnableEurekaClient
@SpringBootApplication
public class ServiceClient01BootStarp {
    //开启软均衡负载
    @LoadBalanced
    @Bean
    RestTemplate restTemplate() {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        SpringApplication.run(ServiceClient01BootStarp.class, args);
    }
}

package com.jadyer.demo.ribbon;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;
import javax.annotation.Resource;

@Service
class CalculatorService {
    @Resource
    private RestTemplate restTemplate;

    //指定断路后的回调方法（回调方法必须与原方法参数类型相同、返回值类型相同、方法名可以不同）
    @HystrixCommand(fallbackMethod="addServiceToFallback")
    int addService(int a, int b){
        String reqURL = "http://CalculatorServer/add?a=" + a + "&b=" + b;
        return restTemplate.getForEntity(reqURL, Integer.class).getBody();
    }

    public int addServiceToFallback(int aa, int bb){
        return -999;
    }
}

package com.jadyer.demo.ribbon;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;

/**
 * 服务调用方
 * Created by 玄玉<https://jadyer.cn/> on 2017/1/10 18:23.
 */
@RestController
@RequestMapping("/demo/ribbon")
public class ConsumerController {
    @Resource
    private CalculatorService calculatorService;

    @RequestMapping("/toadd")
    int toadd(int a, int b){
        return calculatorService.addService(a, b);
    }
}

package com.jadyer.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;

//开启Feign功能（无需显式@EnableCircuitBreaker，其已含此功能）
@EnableFeignClients
@EnableEurekaClient
@SpringBootApplication
public class ServiceClient02BootStarp {
    public static void main(String[] args) {
        SpringApplication.run(ServiceClient02BootStarp.class, args);
    }
}

package com.jadyer.demo.feign;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

//绑定該接口到CalculatorServer服务，并通知Feign组件对该接口进行代理（不需要编写接口实现）
@FeignClient(value="CalculatorServer", fallback=CalculatorService.HystrixCalculatorService.class)
public interface CalculatorService {
    ////@PathVariable這種也是支持的
    //@RequestMapping(value="/add/{a}", method=RequestMethod.GET)
    //int myadd(@PathVariable("a") int a, @RequestParam("b") int b);

    //通过SpringMVC的注解来配置所綁定的服务下的具体实现
    @RequestMapping(value="/add", method=RequestMethod.GET)
    int myadd(@RequestParam("a") int a, @RequestParam("b") int b);

    /**
     * 这里采用和SpringCloud官方文档相同的做法，把fallback类作为内部类放入Feign接口中
     * http://cloud.spring.io/spring-cloud-static/Camden.SR6/#spring-cloud-feign-hystrix
     * （也可以外面独立定义该类，个人觉得没必要，这种东西写成内部类最合适）
     */
    @Component
    class HystrixCalculatorService implements CalculatorService {
        @Override
        public int myadd(@RequestParam("a") int a, @RequestParam("b") int b) {
            return -999;
        }
    }
}

package com.jadyer.demo.feign;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;

/**
 * 服务调用方
 * Created by 玄玉<https://jadyer.cn/> on 2017/1/10 18:23.
 */
@RestController
@RequestMapping("/demo/feign")
public class ConsumerController {
    @Resource
    private CalculatorService calculatorService;

    @RequestMapping("/toadd")
    int toadd(int a, int b){
        return calculatorService.myadd(a, b);
    }
}