spring cloud 使用Hystrix 实现断路器进行服务容错保护的方法

<project xmlns="http://maven.apache.org/POM/4.0.0"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.sam</groupId>
  <artifactId>hello-consumer</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.1.RELEASE</version>
  </parent>

  <properties>
    <javaVersion>1.8</javaVersion>
  </properties>

  <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-dependencies</artifactId>
        <version>Camden.SR6</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>

  </dependencyManagement>

  <dependencies>
    <!-- 引入eureka 客户端依赖 -->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-eureka</artifactId>
    </dependency>
    <!-- 引入ribbon 依赖 ，用来实现负载均衡，我们这里只是使用先不作其他介绍 -->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-ribbon</artifactId>
    </dependency>
    <!-- 引入hystrix 依赖 ，用来实现服务容错保护-->
    <dependency>
      <groupId>org.springframework.cloud</groupId>
      <artifactId>spring-cloud-starter-hystrix</artifactId>
    </dependency>

  </dependencies>
</project>

@EnableDiscoveryClient
@SpringBootApplication
@EnableCircuitBreaker
public class ConsumerApp {


  //@Bean 应用在方法上，用来将方法返回值设为为bean
  @Bean
  @LoadBalanced //@LoadBalanced实现负载均衡
  public RestTemplate restTemplate() {
    return new RestTemplate();
  }
  
  public static void main(String[] args) {
    SpringApplication.run(ConsumerApp.class, args);
  }
}

@SpringCloudApplication
public class ConsumerApp {
  //@Bean 应用在方法上，用来将方法返回值设为为bean
  @Bean
  @LoadBalanced //@LoadBalanced实现负载均衡
  public RestTemplate restTemplate() {
    return new RestTemplate();
  }
  
  public static void main(String[] args) {
    SpringApplication.run(ConsumerApp.class, args);
  }
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootApplication
@EnableDiscoveryClient
@EnableCircuitBreaker
public @interface SpringCloudApplication {
}

@Service
public class ConsumerService {
  
  @Autowired
  RestTemplate restTemplate;

  @HystrixCommand(fallbackMethod = "errorMsg")
  public String consumer() {
    // 调用hello-service服务，注意这里用的是服务名，而不是具体的ip+port
    restTemplate.getForObject("http://hello-service/hello", String.class);
    return "hello consumer finish !!!";
  }

  public String errorMsg() {
    return "error!!!";
  }
}

/**
 *这里不再直接调用restTemplate，
 *而是通过调用service进行实现 
 *
 */
@RestController
public class ConsumerController {

  @Autowired
//  RestTemplate restTemplate;
  ConsumerService service;
  
  
  @RequestMapping("/hello-consumer")
  public String helloConsumer() {
//    //调用hello-service服务，注意这里用的是服务名，而不是具体的ip+port
//    restTemplate.getForObject("http://hello-service/hello", String.class);
    return service.consumer();
  }
}