Spring-Cloud | openfeign使用細節

寫在前面的話

各位，下午好！

我比較喜歡用 fegin 來實現微服務之間的調用，但是feign使用的那些細節，是get到了嗎？本節我將使用Spring Boot 2.0.5.RELEASE + Spring Cloud SR1 + openfeign並結合實際的使用，教你使用feign的姿勢。

項目架構

我們先對測試架構一番，看圖

簡單來說，就是服務模塊化分爲：model層、API層、service層，其他服務就可以依賴API層。

另外，我們看一下，Spring官網提供的一段關於Feign Inheritance Support代碼：

下面我們就動手寫例子。

測試實例

1、先看一下完成後的目錄截圖

我們看 api、 model、 service、 feign-use之間的依賴關係。 api依賴model service依賴api，實現api接口 feign-use依賴api，client繼承api，並注入spring bean

2、使用公益eureka，這樣我們就省略構建服務註冊中心了

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

3、關於項目多模塊化，看這裏：https://github.com/fengwenyi/multi-module。

4、model中的代碼：

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 {

    /** 標識 */
    private String uuid;

    /** 姓名 */
    private String name;

    /** 年齡 */
    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 {

    /**
     * 獲取users
     * @return
     */
    @GetMapping("/getUsers")
    List<User> getUsers();

    /**
     * 根據用戶ID獲取user
     * @param uuid 用戶ID
     * @return
     */
    @GetMapping("/getUserById/{uuid}")
    User getUserById(@PathVariable("uuid") String uuid);

    /**
     * 添加用戶
     * @param user 用戶對象
     * @return
     */
    @PostMapping("/addUser")
    boolean addUser(@RequestBody User user);

    /**
     * 根據用戶ID修改用戶信息
     * @param uuid 用戶ID
     * @param user
     * @return
     */
    @PostMapping("/updateUserById/{uuid}")
    boolean updateUserById(@PathVariable("uuid") String uuid, @RequestBody User user);

    /**
     * 根據用戶ID修改用戶信息
     * @param uuid 用戶ID
     * @param age 用戶年齡
     * @return
     */
    @PostMapping("/updateById/{uuid}")
    boolean updateUserAgeById(@PathVariable("uuid") String uuid, @RequestBody Integer age);

    /**
     * 根據用戶ID刪除用戶
     * @param uuid 用戶ID
     * @return
     */
    @DeleteMapping("/deleteUserById/{uuid}")
    boolean deleteUserById(@PathVariable("uuid") String uuid);
}

6、API實現

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對應的user已被替換，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對應的user已被替換，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對應的user已被替換，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對應的user已被刪除，uuid={}, lastUser={}", uuid, lastUser);

        return true;
    }
}

7、API繼承

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、寫調用測試代碼

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("張三")
                .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("張三 - 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);
    }
}

關於測試

1、添加操作

http://localhost:8080/add/張三/19
http://localhost:8080/add/李四/18
http://localhost:8080/add/王五/17

2、查詢

我們通過這個接口，看一下添加的情況：

http://localhost:8080/gets

響應不好意思，上面代碼有點問題。修改了下。

[
    {
        "uuid":"fddde49a35fe4947950571a93ebfaa1d",
        "name":"張三",
        "age":19
    },
    {
        "uuid":"e136860677a7463d8bcc3c88e0801931",
        "name":"王五",
        "age":17
    },
    {
        "uuid":"b440ebdf36964b62aea2025549409d4a",
        "name":"李四",
        "age":18
    }
]

單個查詢

http://localhost:8080/get/e136860677a7463d8bcc3c88e0801931

響應

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

3、修改操作

http://localhost:8080/updateUser/e136860677a7463d8bcc3c88e0801931

修改之後，數據是這樣子的

[
    {
        "uuid":"fddde49a35fe4947950571a93ebfaa1d",
        "name":"張三",
        "age":19
    },
    {
        "uuid":"e136860677a7463d8bcc3c88e0801931",
        "name":"張三 - Zhangsan",
        "age":21
    },
    {
        "uuid":"b440ebdf36964b62aea2025549409d4a",
        "name":"李四",
        "age":18
    }
]

4、刪除

http://localhost:8080/delete/b440ebdf36964b62aea2025549409d4a

刪除之後，數據是這樣子的

[
    {
        "uuid":"fddde49a35fe4947950571a93ebfaa1d",
        "name":"張三",
        "age":19
    },
    {
        "uuid":"e136860677a7463d8bcc3c88e0801931",
        "name":"張三 - Zhangsan",
        "age":21
    }
]

5、看一下控制檯

2018-09-15 13:54:34.304  WARN 9732 --- [qtp489047267-34] c.fengwenyi.service.FeignAPIApplication  : 
uuid對應的user已被替換，uuid=e136860677a7463d8bcc3c88e0801931, 
lastUser=User(uuid=e136860677a7463d8bcc3c88e0801931, name=王五, age=17), 
user=User(uuid=e136860677a7463d8bcc3c88e0801931, name=張三 - Zhangsan, age=21)

2018-09-15 13:56:18.367  WARN 9732 --- [qtp489047267-35] c.fengwenyi.service.FeignAPIApplication  : 
uuid對應的user已被刪除，uuid=b440ebdf36964b62aea2025549409d4a, 
lastUser=User(uuid=b440ebdf36964b62aea2025549409d4a, name=李四, age=18)

測試代碼

點擊這裏，查看本節測試代碼。

大抵就是這樣子，感謝。

Spring-Cloud | openfeign使用細節

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