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分享Java泛型继承的问题，有高手可以解答下吗？
public abstract class BaseEntity<T> implements Serializable {
...
}
public abstract class DataEntity<T> extends BaseEntity<T>{
...
}
public class User extends DataEntity<User>{
...
}
public class Scholar extends User {
...
}
public abstract class CrudService<D extends CrudDao<T>, T extends DataEntity<T>> extends BaseService{
...
}
public class ScholarService extends CrudService<ScholarDao, Scholar>{ //这个地方编译出错
...
}
错误信息：Multiple markers at this line
- Bound mismatch: The type Scholar is not a valid substitute for the bounded parameter <T extends DataEntity<T>> of the type
CrudService<D,T>
...
}
public abstract class DataEntity<T> extends BaseEntity<T>{
...
}
public class User extends DataEntity<User>{
...
}
public class Scholar extends User {
...
}
public abstract class CrudService<D extends CrudDao<T>, T extends DataEntity<T>> extends BaseService{
...
}
public class ScholarService extends CrudService<ScholarDao, Scholar>{ //这个地方编译出错
...
}
错误信息：Multiple markers at this line
- Bound mismatch: The type Scholar is not a valid substitute for the bounded parameter <T extends DataEntity<T>> of the type
CrudService<D,T>
...全文
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ilmlife 2015-07-17
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你的Scholar 不满足T extends DataEntity<T> 编译是不会通过的
Scholar 继承自User而传入的类型是User
而你下面的参数是T extends DataEntity<T>
而你现在写的相当于Scholar extends DataEntity<User>
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