JPA 生成实体类报错 is managed, but is not listed in the persistence.xml file 解决方法（标识码）

Class "com.taiji.apps.demo.domain.Sample.java"  is managed, but is not listed in the persistence.xml file，

解决方法为右键工程->properties->点击JPA->点击"Discover annotated classes automatically"前面的按钮，点击ok，问题解决