避免类型安全警告使用Hibernate Query.list() [英] Avoiding Type Safety Warnings Using Hibernate Query.list()
问题描述
使用createQuery()。list?之后,是否可以避免强制转换警告?
//类型安全:类型List需要未检查的转换以符合List< User>
List< User> user =(List< User>)session.createQuery(select u from User u)list();
我希望找到一个通过通用参数或方法参数指定目标对象的方法, :
列表< User> user = session.createQuery(select u from User u)。list(User.class);
要记住的最重要的事情是警告是由于您的编译器,而不是hibernate - 您可以告诉您的编译器忽略未实现的泛型。通过使用HQL,我们以类型安全的方式查询数据,不幸的是,java不能验证。
有很多如果得到的方法围绕hibernate转换的语法丑陋,像:
1)使用@suppressWarnings在其中转换或
<请使用Collections.checkedList方法创建新列表。
Is it possible to avoid cast warnings after using createQuery().list?
//Type safety: The expression of type List needs unchecked conversion to conform to List<User>
List<User> user = (List<User>) session.createQuery("select u from User u").list();
I expected to find a method that specified the target object via generic parameter or method parameter such as the following:
List<User> user = session.createQuery("select u from User u").list(User.class);
The most important thing to remember is that warnings are due to your compiler, not hibernate - you can tell your compiler to ignore unimplemented generics. By using HQL, we are querying for data in a type safe way that, unfortunately, java does not have the ability to verify.
There are a lot if ways to get around the syntactical ugliness of hibernate casting , like :
1) use @suppressWarnings where casting or
2) use the Collections.checkedList method to create the new list.
See also : How to avoid type safety warnings with Hibernate HQL results?
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