与Maven的约定是在target/generated-sources/中生成代码，例如target/generated-sources/jaxb2

The convention with Maven is to generate code in target/generated-sources/<tool>, for example target/generated-sources/jaxb2

遵循此约定，IDEA 会将文件夹添加为源文件夹(请参阅 IDEA-53198).

Follow this convention and IDEA will add the folder as source folder (see IDEA-53198).