Spring-Cloud | openfeign使用细节

写在前面的话

各位，下午好！

我比较喜欢用 fegin 来实现微服务之间的调用，但是feign使用的那些细节，是get到了吗？本节我将使用Spring Boot 2.0.5.RELEASE + Spring Cloud SR1 + openfeign并结合实际的使用，教你使用feign的姿势。

项目架构

我们先对测试架构一番，看图

简单来说，就是服务模块化分为：model层、API层、service层，其他服务就可以依赖API层。

另外，我们看一下，Spring官网提供的一段关于Feign Inheritance Support代码：

下面我们就动手写例子。

测试实例

1、先看一下完成后的目录截图

我们看 api、 model、 service、 feign-use之间的依赖关系。
api依赖model
service依赖api，实现api接口
feign-use依赖api，client继承api，并注入spring bean

2、使用公益eureka，这样我们就省略构建服务注册中心了

eureka: client: service-url: defaultZone: http://eureka.fengwenyi.com/eureka/

3、关于项目多模块化，看这里：https://github.com/fengwenyi/multi-module。

4、model中的代码：

import lombok.Data; import lombok.EqualsAndHashCode; import lombok.experimental.Accessors; /** * @author Wenyi Feng * @since 2018-09-15 */ @Data @EqualsAndHashCode(callSuper = false) @Accessors(chain = true) public class User { /** 标识 */ private String uuid; /** 姓名 */ private String name; /** 年龄 */ private Integer age; }

5、API接口

import com.fengwenyi.data.model.User; import org.springframework.web.bind.annotation.*; import java.util.List; /** * @author Wenyi Feng * @since 2018-09-15 */ public interface API { /** * 获取users * @return */ @GetMapping("/getUsers") List<User> getUsers(); /** * 根据用户ID获取user * @param uuid 用户ID * @return */ @GetMapping("/getUserById/{uuid}") User getUserById(@PathVariable("uuid") String uuid); /** * 添加用户 * @param user 用户对象 * @return */ @PostMapping("/addUser") boolean addUser(@RequestBody User user); /** * 根据用户ID修改用户信息 * @param uuid 用户ID * @param user * @return */ @PostMapping("/updateUserById/{uuid}") boolean updateUserById(@PathVariable("uuid") String uuid, @RequestBody User user); /** * 根据用户ID修改用户信息 * @param uuid 用户ID * @param age 用户年龄 * @return */ @PostMapping("/updateById/{uuid}") boolean updateUserAgeById(@PathVariable("uuid") String uuid, @RequestBody Integer age); /** * 根据用户ID删除用户 * @param uuid 用户ID * @return */ @DeleteMapping("/deleteUserById/{uuid}") boolean deleteUserById(@PathVariable("uuid") String uuid); }

6、API实现

import com.fengwenyi.data.API; import com.fengwenyi.data.model.User; import lombok.extern.slf4j.Slf4j; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.util.StringUtils; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController; import java.util.ArrayList; import java.util.HashMap; import java.util.List; import java.util.Map; @SpringBootApplication @EnableDiscoveryClient @RestController @Slf4j public class FeignAPIApplication implements API { public static void main(String[] args) { SpringApplication.run(FeignAPIApplication.class, args); // ApplicationContextAware // BeanUtils } Map<String, User> userMap = new HashMap<>(); @Override public List<User> getUsers() { if (userMap == null || userMap.isEmpty()) return null; List<User> userList = new ArrayList<>(); for (String uuid : userMap.keySet()) { userList.add(userMap.get(uuid)); } return userList; } @Override public User getUserById(@PathVariable String uuid) { if (userMap == null || userMap.isEmpty() || StringUtils.isEmpty(uuid)) return null; return userMap.get(uuid); } @Override public boolean addUser(@RequestBody User user) { if (user == null) return false; String uuid = user.getUuid(); if (uuid == null) return false; if (userMap.get(uuid) != null) return false; User lastUser = userMap.put(uuid, user); if (lastUser != null) log.warn("uuid对应的user已被替换，uuid={}, lastUser={}, user={}", uuid, lastUser, user); return true; } @Override public boolean updateUserById(@PathVariable String uuid, @RequestBody User user) { if (user == null || uuid == null) return false; if (userMap.get(uuid) == null) return false; User lastUser = userMap.put(uuid, user); if (lastUser != null) log.warn("uuid对应的user已被替换，uuid={}, lastUser={}, user={}", uuid, lastUser, user); return true; } @Override public boolean updateUserAgeById(@PathVariable String uuid, @RequestBody Integer age) { if (age == null || uuid == null || age < -1) return false; User user = userMap.get(uuid); if (user == null) return false; User lastUser = userMap.put(uuid, user.setAge(age)); if (lastUser != null) log.warn("uuid对应的user已被替换，uuid={}, lastUser={}, user={}", uuid, lastUser, user); return true; } @Override public boolean deleteUserById(@PathVariable String uuid) { if (uuid == null) return false; if (userMap.get(uuid) == null) return false; User lastUser = userMap.remove(uuid); if (lastUser != null) log.warn("uuid对应的user已被删除，uuid={}, lastUser={}", uuid, lastUser); return true; } }

7、API继承

import com.fengwenyi.data.API; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.stereotype.Component; /** * @author Wenyi Feng * @since 2018-09-15 */ @FeignClient("feignapi") public interface APIClient extends API { }

8、写调用测试代码

import com.fengwenyi.data.model.User; import com.fengwenyi.javalib.util.StringUtil; import com.fengwenyi.javalib.util.Utils; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.openfeign.EnableFeignClients; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RestController; @SpringBootApplication @EnableDiscoveryClient @EnableFeignClients @RestController public class FeignUseApplication { public static void main(String[] args) { SpringApplication.run(FeignUseApplication.class, args); } @Autowired private APIClient apiClient; @GetMapping("/add/{name}/{age}") public Object add(@PathVariable("name") String name, @PathVariable("age") Integer age) { if (StringUtil.isEmpty(name) || age == null || age < 0) return false; return apiClient.addUser(new User() .setUuid(Utils.getUUID()) .setName("张三") .setAge(20)); } @GetMapping("/updateUser/{uuid}") public Object updateUser(@PathVariable("uuid") String uuid) { if (StringUtil.isEmpty(uuid)) return false; User user = apiClient.getUserById(uuid); if (user == null) return false; return apiClient.updateUserById(uuid, user.setName("张三 - Zhangsan") .setAge(21)); } @GetMapping("/update/{uuid}") public Object update(@PathVariable("uuid") String uuid) { if (StringUtil.isEmpty(uuid)) return false; User user = apiClient.getUserById(uuid); if (user == null) return false; return apiClient.updateUserAgeById(uuid, 23); } @GetMapping("/delete/{uuid}") public Object delete(@PathVariable("uuid") String uuid) { if (StringUtil.isEmpty(uuid)) return false; User user = apiClient.getUserById(uuid); if (user == null) return false; return apiClient.deleteUserById(uuid); } @GetMapping("gets") public Object gets() { return apiClient.getUsers(); } @GetMapping("/get/{uuid}") public Object get(@PathVariable("uuid") String uuid) { if (StringUtil.isEmpty(uuid)) return null; return apiClient.getUserById(uuid); } }

关于测试

1、添加操作

http://localhost:8080/add/张三/19 http://localhost:8080/add/李四/18 http://localhost:8080/add/王五/17

2、查询

我们通过这个接口，看一下添加的情况：

http://localhost:8080/gets

响应
不好意思，上面代码有点问题。修改了下。

[ { "uuid":"fddde49a35fe4947950571a93ebfaa1d", "name":"张三", "age":19 }, { "uuid":"e136860677a7463d8bcc3c88e0801931", "name":"王五", "age":17 }, { "uuid":"b440ebdf36964b62aea2025549409d4a", "name":"李四", "age":18 } ]

单个查询

http://localhost:8080/get/e136860677a7463d8bcc3c88e0801931

响应

{ "uuid":"e136860677a7463d8bcc3c88e0801931", "name":"王五", "age":17 }

3、修改操作

http://localhost:8080/updateUser/e136860677a7463d8bcc3c88e0801931

修改之后，数据是这样子的

[ { "uuid":"fddde49a35fe4947950571a93ebfaa1d", "name":"张三", "age":19 }, { "uuid":"e136860677a7463d8bcc3c88e0801931", "name":"张三 - Zhangsan", "age":21 }, { "uuid":"b440ebdf36964b62aea2025549409d4a", "name":"李四", "age":18 } ]

4、删除

http://localhost:8080/delete/b440ebdf36964b62aea2025549409d4a

删除之后，数据是这样子的

[ { "uuid":"fddde49a35fe4947950571a93ebfaa1d", "name":"张三", "age":19 }, { "uuid":"e136860677a7463d8bcc3c88e0801931", "name":"张三 - Zhangsan", "age":21 } ]

5、看一下控制台

2018-09-15 13:54:34.304 WARN 9732 --- [qtp489047267-34] c.fengwenyi.service.FeignAPIApplication : uuid对应的user已被替换，uuid=e136860677a7463d8bcc3c88e0801931, lastUser=User(uuid=e136860677a7463d8bcc3c88e0801931, name=王五, age=17), user=User(uuid=e136860677a7463d8bcc3c88e0801931, name=张三 - Zhangsan, age=21) 2018-09-15 13:56:18.367 WARN 9732 --- [qtp489047267-35] c.fengwenyi.service.FeignAPIApplication : uuid对应的user已被删除，uuid=b440ebdf36964b62aea2025549409d4a, lastUser=User(uuid=b440ebdf36964b62aea2025549409d4a, name=李四, age=18)

测试代码

点击这里，查看本节测试代码。

大抵就是这样子，感谢。