首先是服务提供者
项目结构
导入依赖
<!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-netflix-hystrix -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
<version>2.2.10.RELEASE</version>
</dependency>
对需要降级的服务开启注解@HystrixCommand(fallbackMethod = “hystrixGet”)
@RestController
public class DeptController {
@Autowired
private DeptService service;
@GetMapping("/dept/get/{id}")
@HystrixCommand(fallbackMethod = "hystrixGet")
public Dept get(@PathVariable("id") Long id){
Dept dept = service.queryById(id);
if(dept == null){
throw new RuntimeException("id=>"+id+",不存在该用户");
}
return dept;
}
//备选方法
public Dept hystrixGet(@PathVariable("id") Long id){
return new Dept()
.setDeptno(id)
.setDname("id=>"+id+"无对应信息,null--@Hystrix")
.setDb_source("MySQL中没有该数据库");
}
}
主启动类中添加熔断支持@EnableHystrix
@SpringBootApplication
@EnableEurekaClient //服务启动后自动注册到Eureka中
@EnableDiscoveryClient //服务发现
@EnableHystrix //熔断支持
public class DeptProviderHystrix_8001 {
public static void main(String[] args) {
SpringApplication.run(DeptProviderHystrix_8001.class, args);
}
}
在访问不存在的用户时,触发熔断机制
而没有熔断机制的服务端