我有一个hibernate-mapped Java对象， JKL ，它充满了一堆正常的hibernate-mappable字段（比如字符串和整数）。
我为它添加了一个新的嵌入字段（它位于同一个表中 - 不是映射）， asdf ，这是一个 fj.data.Option< ASDF> 。我已经提出了一个选项来说明这个字段实际上可能不包含任何内容（而不是每次访问时都必须处理 null ）。
如何在我的 JKL.hbm.xml 文件中设置映射？我希望hibernate自动将数据库中的 null 转换为 fj的 none .data.Option< ASDF> 当它检索对象。它还应该将 ASDF 的非空实例转换为某些的 fj.data 。选项< ASDF> 。还有什么我不得不做的吗？谢谢。
解决方案我会建议在访问器中引入FunctionalJava的 Option （getter和setter），同时让Hibernate处理一个简单的java字段，该字段允许为 null 。
例如，对于可选的整数字段：
// SQL CREATE TABLE`JKL`（`JKL_ID` INTEGER PRIMARY KEY，`MY_FIELD` INTEGER DEFAULT NULL ） 您可以直接映射Hibernate专用字段： // Java @Column（nullable = true）私人整数myField;然后，您可以在访问器中引入 Option border：
// Java public fj.data.Option< Integer> getMyField（）{ return fj.data.Option.fromNull（myField）; } public void setMyField（fj.data.Option< Integer> value）{ myField = value.toNull（）; }这是否符合您的需求？
I have a hibernate-mapped Java object, JKL, which is full of a bunch of normal hibernate-mappable fields (like strings and integers).
I'm added a new embedded field to it (which lives in the same table -- not a mapping), asdf, which is a fj.data.Option<ASDF>. I've made it an option to make it clear that this field may not actually contain anything (as opposed to having to handle null every time I access it).
How do I set up the mapping in my JKL.hbm.xml file? I'd like hibernate to automatically convert a null in the database to a none of fj.data.Option<ASDF> when it retrieves the object. It should also convert a non-null instance of ASDF to a some of fj.data.Option<ASDF>. Is there any other trickery that I have to do? Thank you.
解决方案I would suggest introducing FunctionalJava's Option in the accessors (getter and setter), while leaving Hibernate to handle a simple java field which is allowed to be null.
For example, for an optional Integer field:
// SQL CREATE TABLE `JKL` ( `JKL_ID` INTEGER PRIMARY KEY, `MY_FIELD` INTEGER DEFAULT NULL )You can map a Hibernate private field directly:
// Java @Column(nullable = true) private Integer myField;You could then introduce Option at the accessor boundary:
// Java public fj.data.Option<Integer> getMyField() { return fj.data.Option.fromNull(myField); } public void setMyField(fj.data.Option<Integer> value) { myField = value.toNull(); }Does that work for your needs?
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