SpringCloud之Feign

痛定思痛。 2021-11-16 10:54 358阅读 0赞

一、Feign简介

Feign可以把Rest的请求进行隐藏，伪装成类似SpringMVC的Controller一样。你不用再自己拼接url，拼接参数等等操作，一切都交给Feign去做。

1.1、Feign的简介

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM4MjY0OTk5_size_16_color_FFFFFF_t_70][]

二、Feign的快速入门

2.1、导入依赖

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

2.2、启动类上添加注解

@EnableFeignClients

2.3、编写接口，使用Feign，告诉器请求参数，请求方式，返回参数，请求路径

package cn.waggag.client;
    
    import cn.waggag.domain.User;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PathVariable;
    
    /**
     * @description:
     * @author: waggag
     * @time: 2019/7/28 11:36
     * @Company http://www.waggag.cn
     */
    //指定服务，到指定的服务访问
    @FeignClient("user-service")
    public interface UserClient {
    
        @GetMapping("user/{id}")
        User queryById(@PathVariable("id") int id);
    }

2.4、在Controller中使用

@Autowired
        private UserClient userClient;
        
        @GetMapping("{id}")
        public User queryById(@PathVariable("id")int id){
            return userClient.queryById(id);
        }

2.5、Feign的配置

#开启Feign的Hystrix熔断
    feign:
      hystrix:
        enabled: true
    #Feign的默认Ribbon（负载均衡）的设置
    ribbon:
      ConnectionTimeOut: 500
      ReadTimeOut: 2000

2.6、Feign的熔断配置，配置接口的实现类。

package cn.waggag.client;
    
    import cn.waggag.domain.User;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.PathVariable;
    
    /**
     * @description:
     * @author: waggag
     * @time: 2019/7/28 11:36
     * @Company http://www.waggag.cn
     */
    @FeignClient(value = "user-service",fallback = UserClientImpl.class)
    public interface UserClient {
    
        @GetMapping("user/{id}")
        User queryById(@PathVariable("id") int id);
    }

2.7、熔断类的实现，编写熔断逻辑

package cn.waggag.client;
    
    import cn.waggag.domain.User;
    import org.springframework.stereotype.Component;
    
    /**
     * @description:
     * @author: waggag
     * @time: 2019/7/28 11:57
     * @Company http://www.waggag.cn
     */
    @Component
    public class UserClientImpl implements UserClient {
        @Override
        public User queryById(int id) {
            User user = new User();
            user.setUsername("Feign的熔断测试");
            return user;
        }
    }

2.8、Feign中包含Ribbon和Hystrix，可以直接在Feign中进行配置。

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