话题一：如何使用Hystrix

• 1.创建一个最简单的Consumer
• 2.在配置文件中添加对Hystrix的引用

    <dependencies>
        <!-- 连接hystrix配置 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>
        <!-- 连接Eureka配置，将微服务注册到Eureka上面 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka</artifactId>
        </dependency>
        <!-- 连接Feign配置 -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-feign</artifactId>
        </dependency>
        <!-- actuator监控器 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

3.在主程序启动的地方添加@EnableCircuitBreaker

    @SpringBootApplication
    @EnableEurekaClient
    @EnableCircuitBreaker
    public class ServerConsumeHystrixApplication {
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate() {
            return new RestTemplate();
        }
      
        public static void main(String[] args) {
            SpringApplication.run(ServerConsumeHystrixApplication.class, args);
        }
    }

• 4.在要进行断路的方法前面添加配置

@HystrixCommand(fallbackMethod="findByIdFallBack")
创建一个参数一模一样的方法，返回默认值

• 5.#设置Hystrix的超时时间（配置版）

    hystrix.command.default.execution.isolation.thread.timeoutInMilliseconds: 500
    hystrix.command.default.execution.timeout.enabled:  false

6.#设置Hystrix的超时时间（标注版）

    @GetMapping("/movie/{id}")
    @HystrixCommand(commandProperties = {
              @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value = "5000"),
              @HystrixProperty(name = "execution.timeout.enabled", value = "false")},fallbackMethod="findByIdFallBack")
    public User findById(@PathVariable Long id) {
      return this.restTemplate.getForObject("http://server-provider/simple/" + id, User.class);
    }