标签：variable VID frame erro nbsp from 架构 配置 服务提供者
熔断机制，指的是微服务架构中，由于某个服务瘫痪，为避免影响整个系统而采取的降级服务
简述：
由于网络或自身原因，服务不能确保一定可用。如果某个服务出现了问题，调用方的大量请求会使Servlet容器的线程资源被耗尽，导致服务瘫痪。而且这种故障会传播，进而威胁到这个微服务系统可用性
示例如下：基于springboot1.5.10
添加依赖：
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<version>1.5.10.RELEASE</version>
</dependency>
<!--Eureka 客户端-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>1.4.3.RELEASE</version>
</dependency>
<!--hystrix断路器-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
<version>1.4.3.RELEASE</version>
</dependency>
application配置
server:
port: 8901 #程序启动端口，也是Tomcat端口
spring:
application:
name: customer-order-hystrix #应用别名
eureka:
client:
service-url:
defaultZone: http://user:123@localhost:10000/eureka
instance:
instance-id: ${spring.cloud.client.ipAddress}:${spring.application.name}:${spring.application.instance_id:${server.port}}
prefer-ip-address: true
启动类
@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker //启用熔断
public class CustomerHystrixApplication
{
@Bean
public RestTemplate getTemp(){
return new RestTemplate();
}
public static void main( String[] args )
{
SpringApplication.run(CustomerHystrixApplication.class,args);
System.out.println("customer start-up success");
}
}
实体类
public class User {
private Long id;
private Date date;
public User() {
}
public User(Long id) {
this.id = id;
this.date = new Date();
}
public void setId(Long id) {
this.id = id;
}
public void setDate(Date date) {
this.date = date;
}
public Long getId() {
return id;
}
public Date getDate() {
return date;
}
Controller
@RestController
public class CustomeController {
@Autowired
private EurekaClient eurekaClient;
@Autowired
private RestTemplate restTemplate;//springboot提供的用于访问rest接口的对象
@GetMapping("/order/{id}")
@HystrixCommand(fallbackMethod = "errora1")
public User getOrder(@PathVariable Long id){
InstanceInfo instanceInfo = eurekaClient.getNextServerFromEureka("provider-user", false);
String homePageUrl = instanceInfo.getHomePageUrl();
// 访问提供者，获取数据
User user = restTemplate.getForObject(homePageUrl+"/user/" + id,User.class);//通过访问rest获取json数据，然后转换成user对象
return user;
}
/**
* 失败后执行的回调函数
* @param id
* @return
*/
public User errora1(Long id) {
User user = new User();
user.setId(-1000L);
user.setDate(new Date());
return user;
}
}
注：回调函数和其使用者应返回相同的类型，这里省略了服务提供者模块 provider-user
标签：variable VID frame erro nbsp from 架构 配置 服务提供者
原文地址：https://www.cnblogs.com/jincheng81/p/12575186.html
