远程调用 Spring Cloud Feign

蔚落 2021-12-19 17:13 214阅读 0赞

# 一、 Feign简介 #

Feign \[feɪn\] 译文 伪装。Feign是一个声明式WebService客户端.使用Feign能让编写WebService客户端更加简单,它的使用方法是定义一个接口，然后在上面添加注解。不再需要拼接URL，参数等操作。项目主页：[https://github.com/OpenFeign/feign][https_github.com_OpenFeign_feign] 。

*  集成Ribbon的负载均衡功能
 *  集成了Hystrix的熔断器功能
 *  支持请求压缩
 *  大大简化了远程调用的代码，同时功能还增强啦
 *  Feign以更加优雅的方式编写远程调用代码，并简化重复代码

# 快速入门 #

实现步骤：

1.  导入feign依赖
2.  编写Feign客户端接口
3.  消费者启动引导类开启Feign功能注解
4.  访问接口测试

## 1. 导入feign依赖 ##

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

## 1.1创建实体类User ##

package com.william.domain;
    
    import java.util.Date;
    
    /**
     * @author ：lijunxuan
     * @date ：Created in 2019/6/30  18:20
     * @description ：
     * @version: 1.0
     */
    public class User {
        private Integer id;//主键id
        private String username;//用户名
        private String password;//密码
        private String name;//姓名
        private Integer age;//年龄
        private Integer sex;//性别 1男性，2女性
        private Date birthday; //出生日期
        private Date created; //创建时间
        private Date updated; //更新时间
        private String note;//备注
    
        @Override
        public String toString() {
            return "User{" +
                    "id=" + id +
                    ", username='" + username + '\'' +
                    ", password='" + password + '\'' +
                    ", name='" + name + '\'' +
                    ", age=" + age +
                    ", sex=" + sex +
                    ", birthday=" + birthday +
                    ", created=" + created +
                    ", updated=" + updated +
                    ", note='" + note + '\'' +
                    '}';
        }
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public String getPassword() {
            return password;
        }
    
        public void setPassword(String password) {
            this.password = password;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public Integer getSex() {
            return sex;
        }
    
        public void setSex(Integer sex) {
            this.sex = sex;
        }
    
        public Date getBirthday() {
            return birthday;
        }
    
        public void setBirthday(Date birthday) {
            this.birthday = birthday;
        }
    
        public Date getCreated() {
            return created;
        }
    
        public void setCreated(Date created) {
            this.created = created;
        }
    
        public Date getUpdated() {
            return updated;
        }
    
        public void setUpdated(Date updated) {
            this.updated = updated;
        }
    
        public String getNote() {
            return note;
        }
    
        public void setNote(String note) {
            this.note = note;
        }
    }

## 2. 编写Feign客户端接口 ##

package com.william.service;
    
    import com.william.domain.User;
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestParam;
    
    @FeignClient("user-service")
    public interface UserClient {
        /**
         *RequestMapping
         * spring mvc 里面的注解
         * RequestMapping 反向映射，生成请求地址。http请求
         *  @RequestParam("id") 是必须要进行请求地址参数的绑定
         * @param id
         * @return
         */
        @RequestMapping("/user/findById")
        User findById(@RequestParam("id") Integer id);
    }

## 3. 消费者启动引导类DemoApplication开启Feign功能注解 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70]

@EnableFeignClients//开启feign客户端支持

## 3.1编写ConsumerFeignController，使用UserClient访问 ##

package com.william.controller;
    
    import com.william.domain.User;
    import com.william.service.UserClient;
    import org.springframework.stereotype.Repository;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.annotation.Resource;
    
    /**
     * @author ：lijunxuan
     * @date ：Created in 2019/6/30  18:33
     * @description ：
     * @version: 1.0
     */
    @RestController
    public class FeigConsumerController {
        @Resource
         UserClient userClient;//注入FeignCLient
        @RequestMapping("/findByIdFeign")
        public User findByIdFeign(Integer id){
            return userClient.findById(id);
        }
    }

## 4. 访问接口测试 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3NpbmF0XzM5MTc5OTkz_size_16_color_FFFFFF_t_70 1]  
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[https_github.com_OpenFeign_feign]: https://github.com/OpenFeign/feign
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