Dubbo服务容错（整合hystrix）

简介：Hystrix旨在通过控制那些访问远程系统、服务和第三方库的节点从而对延迟和故障提供更强大的容错能力，Hystrix具备拥有回退机制和断路器功能的线程和信号隔离、请求缓存和请求打包以及监控和配置等功能。

1）、在pom文件中导入依赖（服务提供者和服务消费者都需要导入）

1         <dependency>
2             <groupId>org.springframework.cloud</groupId>
3             <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
4             <version>1.4.4.RELEASE</version>
5         </dependency>

2）、在主程序启动类上添加@EnableHystrix注解开启服务容错（服务提供者和服务消费者都需要添加）

 1 package cn.coreqi;
 2 
 3 import com.alibaba.dubbo.config.spring.context.annotation.EnableDubbo;
 4 import org.springframework.boot.SpringApplication;
 5 import org.springframework.boot.autoconfigure.SpringBootApplication;
 6 import org.springframework.cloud.netflix.hystrix.EnableHystrix;
 7 
 8 @SpringBootApplication
 9 @EnableDubbo
10 @EnableHystrix  //开启服务容错
11 public class SpringbootdubboserviceproviderApplication {
12 
13     public static void main(String[] args) {
14         SpringApplication.run(SpringbootdubboserviceproviderApplication.class, args);
15     }
16 
17 }

3）、在服务提供者实现类中方法上添加@HystrixCommand注解

 1 package cn.coreqi.service.impl;
 2 
 3 import cn.coreqi.entities.User;
 4 import cn.coreqi.service.UserService;
 5 import com.alibaba.dubbo.config.annotation.Service;
 6 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
 7 import org.springframework.stereotype.Component;
 8 
 9 import java.util.ArrayList;
10 import java.util.List;
11 
12 @Component  //org.springframework.stereotype.Component
13 @Service    //com.alibaba.dubbo.config.annotation.Service
14 public class UserServiceImpl implements UserService {
15 
16     private static List<User> users = new ArrayList<>();
17 
18     static {
19         users.add(new User(1,"fanqi","123456",1));
20         users.add(new User(2,"zhangsan","123456",1));
21         users.add(new User(3,"lisi","123456",1));
22         users.add(new User(4,"wangwu","123456",1));
23     }
24 
25     @HystrixCommand
26     @Override
27     public void addUser(User user) {
28         users.add(user);
29     }
30 
31     @HystrixCommand
32     @Override
33     public void delById(Integer id) {
34         for (User s:users){
35             if(s.getId() == id){
36                 users.remove(s);
37                 break;
38             }
39         }
40     }
41 
42     @HystrixCommand
43     @Override
44     public void modifyUser(User user) {
45         delById(user.getId());
46         addUser(user);
47     }
48 
49     @HystrixCommand
50     @Override
51     public User getById(Integer id) {
52         for (User s:users){
53             if(s.getId() == id){
54                 return s;
55             }
56         }
57         return null;
58     }
59 
60     @HystrixCommand
61     @Override
62     public List<User> getList() {
63         return users;
64     }
65 }

4）、在服务消费者调用服务提供者的方法上添加@HystrixCommand注解并指定fallbackMethod属性，重写fallbackMethod指定的方法。

 1 package cn.coreqi.controller;
 2 
 3 import cn.coreqi.entities.User;
 4 import cn.coreqi.service.UserService;
 5 import com.alibaba.dubbo.config.annotation.Reference;
 6 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
 7 import org.springframework.stereotype.Controller;
 8 import org.springframework.web.bind.annotation.RequestMapping;
 9 import org.springframework.web.bind.annotation.ResponseBody;
10 
11 import java.util.List;
12 
13 @Controller
14 public class UserController {
15 
16     @Reference()
17     private UserService userService;
18 
19     @HystrixCommand(fallbackMethod = "test1")
20     @ResponseBody
21     @RequestMapping("/users")
22     public List<User> getUsers(){
23         return userService.getList();
24     }
25 
26     public List<User> test1(){
27         return null;
28     }
29 }