英文:

How can I use a rest controller from a different package in Spring?

问题

发生了什么

我正在使用Java和Spring Boot。
我尝试创建一个简单的API。

我有一个名为Example的包。
我有两个子包，分别是config和rest。

在config中有一个名为Application的类，它是我的Spring应用。
在rest中有一个名为TheController的类，它是REST控制器。

目前，当我运行应用程序Application并尝试访问其中一个GET映射时，会出现白色标签错误页面。

然而，如果我将TheController移动到config包中，我就不会遇到这个错误，一切都很顺利。

我尝试过的方法

我尝试过使用导入语句。
com.Example.rest.* 和 com.Example.rest.TheController，但没有结果。

非常感谢您的帮助

英文:

What's going on

I am using Java, Springboot
I am trying to create a simple API.

I have a package called Example.
I have two sub-packages called config and rest.

In config is the class Application, which is my spring app.
In rest is the class TheController which is the rest controller

Currently when i run the app, Application and try and go to one of the get mappings i get a white label error page.

However if i move theController to the config package i do not get this error and it's plain sailing.

What I have tried

I have tried using an import statement.
com.Example.rest.* and com.Example.rest.TheControllerwith no results.

Any help would be appreciated

答案1

得分: 2

在你的应用程序类上添加 @ComponentScan。

```java
package com.example.config;

@SpringBootApplication
@ComponentScan(basePackages = "com.example")
public class SpringBootComponentScanApp {

}

我个人认为将配置放在子包 "com.example.config" 而不是父包 "com.example" 中是一个好主意，但你需要覆盖Spring Boot的默认组件扫描方式。

参见 https://www.baeldung.com/spring-component-scanning

<details>
<summary>英文:</summary>

Add a @ComponentScan on your application class.

    package com.example.config;

    @SpringBootApplication
    @ComponentScan(basePackages = &quot;com.example&quot;)
    public class SpringBootComponentScanApp {

    }

I personally think it&#39;s a good idea to put your configuration in a sub-package &quot;com.example.config&quot; and not in the parent package &quot;com.example&quot;, but you need to override Spring Boot&#39;s default component scan for that case.

See also https://www.baeldung.com/spring-component-scanning

</details>



# 答案2
**得分**: 0

Spring Boot 只会从应用程序类的包（使用 `@SpringBootApplication` 注解）及其以下位置开始扫描组件（控制器、服务、存储库等）。

因此，最好使用 `com.example.Application`，然后您可以使用 `com.example.rest.TheController`，这样应该可以正常工作。

<details>
<summary>英文:</summary>

Spring Boot will only scan for components (controllers, services, repositories, ...) starting from the package of the application class (annotated with `@SpringBootApplication`) and below.

So best to use `com.example.Application`, then you can use `com.example.rest.TheController` and things should work.

</details>