SpringCloud——Hystrix 知识篇

目录

Hystrix-0 Hystrix 的官方简介

Hystrix-1 Hystrix 的开发步骤

Hystrix-1.1 Hystrix fallbackMethod进入

Hystrix-2.1 Health——commandProperties 

Indicator及Metrics Streamss

---

• Hystrix-0 Hystrix 的官方简介

1. 官方文档：https://projects.spring.io/spring-cloud/spring-cloud.html#_circuit_breaker_hystrix_clients
2. javanica文档：https://github.com/Netflix/Hystrix/tree/master/hystrix-contrib/hystrix-javanica

• Hystrix-1 Hystrix 的开发步骤

1. 1、添加pom.xml依赖

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

1. 2、 启动类添加注解@EnableCircuitBreaker

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class Hystrix001Application {

   @Bean
   public RestTemplate restTemplate() {
      return new RestTemplate();
   }
   public static void main(String[] args) {
      SpringApplication.run(Hystrix001Application.class, args);
   }

}

1. 3、方法名称中添加注解@HystrixCommand，并且自定义返回方法【返回方法的参数返回值、入参一定要和注解相同】

@RestController
public class MovieController {
    @Autowired
    private RestTemplate restTemplate;

    @Value("${user.userServicePath}")
    private String userServicePath;

    @GetMapping("/movie/{id}")
    @HystrixCommand(fallbackMethod = "findByIdfallback")
    public User findById(@PathVariable Long id) {
        return this.restTemplate.getForObject(this.userServicePath + id, User.class);
    }

    public User findByIdfallback() {
        User user = new User();
        user.setId(1110504125L);
        user.setName("xuhy");
        System.out.println("断啦");
        return user;
    }
}

1. 4、其他内容

• 实体类User.java

//因为通过RestTemplate调用不需要jpa的注解内容
public class User {
    private Long id;

    private String username;

    private String name;

    private Short age;

    private BigDecimal balance;

    public Long getId() {
        return this.id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return this.username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Short getAge() {
        return this.age;
    }

    public void setAge(Short age) {
        this.age = age;
    }

    public BigDecimal getBalance() {
        return this.balance;
    }

    public void setBalance(BigDecimal balance) {
        this.balance = balance;
    }

}

• application.yml

server:
  port: 7901
user:
  userServicePath: http://localhost:7900/simple/
eureka:
  client:
    serviceUrl:
      defaultZone: http://user:123@localhost:8761/eureka

  instance:
      prefer-ip-address: true
      instance-id: ${spring.application.name}:${spring.application.instance-id:${server.port}}
spring:
  application:
    name: hystrix-001

1. 5、测试结果http://192.168.4.160:7901/movie/1

{
    "id": 0,
    "username": null,
    "name": "xuhy",
    "age": null,
    "balance": null
}

• Hystrix-1.1 Hystrix fallbackMethod进入

将用户服务等其中一份服务断掉，则会直接进入fallbackMethod方法中，控制台会打印断啦两个字。

• Hystrix-2.1 Health——commandProperties 

1. .1、官方文档：https://projects.spring.io/spring-cloud/spring-cloud.html#_circuit_breaker_hystrix_clients

@HystrixCommand(fallbackMethod = "stubMyService",
    commandProperties = {
      @HystrixProperty(name="execution.isolation.strategy", value="SEMAPHORE")
    }
)

1. 2、内容演示

      

• Hystrix-2.2 Health——autuactor

• Indicator及Metrics Streamss

• 未完待续
•