springcloud系列7——通过代码自定义配置ribbon

缺乏、安全感 2022-05-14 06:26 173阅读 0赞

## 前言 ##

我们这里准备了2组服务：  
\* 2个microservice-springcloud-user服务，端口分别为7902和7904；  
\* 2个microservice-springcloud-user2服务，端口分别为7903和7905；

我们想实现的效果是：microservice-springcloud-user服务随机访问，microservice-springcloud-user2服务顺序访问。下面我们通过代码的方式来实现。

## 创建Ribbon规则 ##

package com.tommy.config;
    
    @Configuration
    public class RibbonChooseConfiguration { 
        @Bean
        public IRule ribbonRule(IClientConfig config) {
            return new RandomRule();
        }
    }

这里指定的规则是随机。  
`The FooConfiguration has to be @Configuration but take care that it is not in a @ComponentScan for the main application context, otherwise it will be shared by all the @RibbonClients. If you use @ComponentScan (or @SpringBootApplication) you need to take steps to avoid it being included (for instance put it in a separate, non-overlapping package, or specify the packages to scan explicitly in the @ComponentScan).`

上面是Spring Cloud官方文档的原文，这里的config类所在的包有一定讲究，就是你的包不能被@ComponentScan或者@SpringBootApplication扫描到。官方文档Ribbon部分：[http://cloud.spring.io/spring-cloud-static/Edgware.SR1/single/spring-cloud.html\#spring-cloud-ribbon][http_cloud.spring.io_spring-cloud-static_Edgware.SR1_single_spring-cloud.html_spring-cloud-ribbon]

## 在应用启动类上配置访问规则 ##

package com.tommy.springcloud;
    @SpringBootApplication
    @EnableEurekaClient
    @RibbonClient(name = "microservice-springcloud-user",configuration = RibbonChooseConfiguration.class)
    public class App { 
        @Bean
        @LoadBalanced
        public RestTemplate restTemplate() {
            return new RestTemplate();
        }
        public static void main( String[] args )
        {
            SpringApplication.run(App.class,args);
        }
    }

这里指定microservice-springcloud-user使用的规则是RibbonChooseConfiguration定义的规则，也就是随机的。

## 测试Controller修改 ##

@RestController
    public class MovieController { 
        @Autowired
        private RestTemplate restTemplate;
        @Autowired
        private LoadBalancerClient loadBalancerClient;
        @GetMapping("/user/{userId}")
        public User getUser(@PathVariable Long userId) {
            return restTemplate.getForObject("http://microservice-springcloud-user/sample/" + userId,User.class);
        }
        @GetMapping(value = "/test")
        public String test() {
            ServiceInstance serviceInstance = loadBalancerClient.choose("microservice-springcloud-user");
            System.out.println(serviceInstance.getServiceId()+"-->"+serviceInstance.getHost()+":"+serviceInstance.getPort());
            ServiceInstance serviceInstance2 = loadBalancerClient.choose("microservice-springcloud-user2");
            System.out.println(serviceInstance2.getServiceId()+"-->"+serviceInstance2.getHost()+":"+serviceInstance2.getPort());
            return "hello,world";
        }
    }

getUser()方法仍然访问microservice-springcloud-user服务，test()方法则2个服务都访问，打印服务的id、ip和端口。

## 测试 ##

*  1.开启2个microservice-springcloud-user服务，端口分别为7902和7904；
 *  2.开启2个microservice-springcloud-user2服务，端口分别为7903和7905；
 *  3.开启microservice-springcloud-movie，进行测试；
 *  4.浏览器输入[http://localhost:7901/user/1][http_localhost_7901_user_1]，查看控制台：  
    ![14020805.jpg][]  
    ![56479550.jpg][]  
    可以看到，microservice-springcloud-user一个控制台打印了3条SQL，一个1条SQL，说明访问是随机的。而我们在代码中指定了Ribbon访问microservice-springcloud-user的规则是随机的，所以说明规则生效了。
 *  5.浏览器输入[http://localhost:7901/test][http_localhost_7901_test]，访问6次  
    ![517566.jpg][]  
    可以看到，microservice-springcloud-user是随机访问的，microservice-springcloud-user2是轮询。

[http_cloud.spring.io_spring-cloud-static_Edgware.SR1_single_spring-cloud.html_spring-cloud-ribbon]: http://cloud.spring.io/spring-cloud-static/Edgware.SR1/single/spring-cloud.html#spring-cloud-ribbon
[http_localhost_7901_user_1]: http://localhost:7901/user/1
[14020805.jpg]: http://omh46px9n.bkt.clouddn.com/18-2-1/14020805.jpg
[56479550.jpg]: http://omh46px9n.bkt.clouddn.com/18-2-1/56479550.jpg
[http_localhost_7901_test]: http://localhost:7901/test
[517566.jpg]: http://omh46px9n.bkt.clouddn.com/18-2-1/517566.jpg