Hibernate query.list() 方法返回空列表而不是空值 [英] Hibernate query.list() method is returning empty list instead of null value

问题描述

当没有行时，query.list() 和 criteria.list() 都返回 空 列表而不是 <代码>空值.

When there are no rows, both query.list() and criteria.list() are returning empty list instead of a null value.

这背后的原因是什么?

推荐答案

原因是不强制在客户端代码中检查空值，与 Effective Java 2nd Edition，Item 43:返回空数组或集合，而不是空值.

The reason is not to force null checks in client code, in consistency with Effective Java 2nd Edition, Item 43: Return empty arrays or collections, not nulls.

这使得客户端代码更简单，更不容易出错(很可能也是方法实现).

This makes the client code simpler and less error-prone (and most likely the method implementation as well).

null-return 惯用语可能是 C 编程语言的遗留物，在哪些数组长度与实际数组分开返回.在 C 中，没有如果返回零作为长度，则分配数组的优势.

The null-return idiom is likely a holdover from the C programming language, in which array lengths are returned separately from actual arrays. In C, there is no advantage to allocating an array if zero is returned as the length.

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