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 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 userMap = new HashMap<>();
@Override
public List getUsers() {
if (userMap == null || userMap.isEmpty())
return null;
List 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/王五/172、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。