feign有假裝的意思

 

為什么要叫假裝？

Feign可以把Rest的請求進行隱藏，偽裝成類似SpringMVC的Controller一樣。你不用再自己拼接url，拼接參數等等操作，一切都交給Feign去做。

 

快速入門

先用起來，我們在使用的時候揭開它神秘的面紗吧

導入依賴

pom.xml 引入：

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

Feign的客戶端

@FeignClient(name = "user",url = "${user.url}")

public interface UserFeign {

    @PostMapping
    void save(User user);

    @GetMapping("/{id}")
    User getUserByID(@PathVariable("id") String id);

    @GetMapping
    List<User> findAll();
}

寫一個Controller

@RequestMapping("user")
@RestController
public class UserController {

    /**
     * 簡單的Map存儲User
     */
    private Map<String, User> userMap = new HashMap<>();

    /**
     * id自增主鍵
     */
    private AtomicLong pk = new AtomicLong();

    @PostMapping
    public void save(@RequestBody User user) {
        String id = String.valueOf(pk.incrementAndGet());
        user.setId(id);
        userMap.put(id, user);
        System.out.println("保存成功");
    }

    @GetMapping("/{id}")
    public User getUserByID(@PathVariable("id") String id) {
        return userMap.get(id);
    }

    @GetMapping
    public List<User> findAll(@RequestHeader("token") String token) {
        System.out.println("請求頭token信息：" + token);
        return new ArrayList<>(userMap.values());
    }
}

dao層

@Data
public class User {

    private String id;

    private String name;

}

啟動類

@SpringBootApplication
@EnableFeignClients
public class ProductApplication {

	public static void main(String[] args) {
		SpringApplication.run(ProductApplication.class, args);
	}

}

測試類

@RunWith(SpringRunner.class)
@SpringBootTest
public class UserFeignTest {
    @Autowired
    UserFeign userFeign;

    @Test
    public void save() {
        User user = new User();
        user.setName("張三");
        userFeign.save(user);
        User user1 = userFeign.getUserByID("1");
        System.out.println(user1);
    }

    @Test
    public void getUserByID() {
        userFeign.getUserByID("1");
    }

    @Test
    public void findAll() {
        List<User> userList = userFeign.findAll();
        System.out.println(userList);
    }

}

application.yml

server:
  port: 8888

spring:
  application:
    name: fegintest


user:
  url: http://localhost:8888/user

logging:
  level:
    com.zxw.feign: debug

先把項目啟動了，端口為：8888

這事 feign 接口 @FeignClient(name = "user",url = "${user.url}")

user.url 為   http://localhost:8888/user

這樣就實現了http 映射到接口上

然后我們在測試類調用 userFeign.save(user) 直接可以映射到 http請求。

直接請求到UserController 類上的 sava方法。

 

可以看到直接用feign 就能調用HTTP接口，真的省了很多功夫