JPA2 +休眠+订购方式
是否可能（使用 Hibernate 和 JPA2 Criteria Builder) 按方法结果而不是实体成员排序？
public class X {
protected X() {}
public String member;
public String getEvaluatedValue() { // order by
return "a status calculated with various members";
}
}
我想要实现的是按 getEvaluatedValue() 的结果排序。这可能吗？
我没有使用@Formular，但
EntityManager em = ...;
QueryBuilder builder = em.getQueryBuilder();
SomeQueryClass query = builder.createQuery(MyTargetClass.class);
query.orderBy(builder.asc(... some code...));
我虽然它是普通的JPA2，当然你是对的，没有机会按动态数据排序。但是我可能被允许使用 if-else 或任何语句（用我的 QueryBuilder 定义）指定一些 order-by 块，不是吗？
Is it possible (using Hibernate and JPA2 Criteria Builder) to order by a methods result rather than an entities member?
public class X {
protected X() {}
public String member;
public String getEvaluatedValue() { // order by
return "a status calculated with various members";
}
}
What I want to achieve is order by the result of getEvaluatedValue(). Is that possible?
I'm not using @Formular, but
EntityManager em = ...;
QueryBuilder builder = em.getQueryBuilder();
SomeQueryClass query = builder.createQuery(MyTargetClass.class);
query.orderBy(builder.asc(... some code...));
I though it is plain JPA2 and certainly you are right there is no chance to order by dynamic data. But I may be allowed to specify some order-by block with an if-else or whatever statement (defined with my QueryBuilder), won't I?
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我不知道这是否可能（如果一个属性是瞬态的，即在数据库中没有表示，那么 SQL 结果应该是什么？）但是，更重要的是，按
"some 排序之间有什么区别？测试“+成员和成员？也许这只是一个例子......I don't know if it is possible (if an attribute is transient i.e. doesn't have a representation in database, what should be the SQL result?) but, more important, what would the difference between ordering by
"some test " + memberandmember? Maybe that's just an example though...看起来这是不可能的，原因如下：
当在SQL层运行查询时，不会计算“EvaluatedValue”字段。它仅在稍后填充（具体时间，我不知道，这可能取决于实体是否使用 LAZY 模式）。
JPA 查询对象与 SQL（即数据库中的内容）紧密相关。
也许，我会使用 getResultList() 获得未排序的结果，然后手动对它们进行排序：
使您的 EvaluatedValue 成为实现 Comparable 的类型：
参见此处
Looks like it cannot be possible, for this reason :
when the query is run in the SQL layer, the "EvaluatedValue" field is not calculated. It is only populated later (when exactly, I dont know, it may depend on if the entity uses a LAZY mode or not).
The JPA Query object is closely tied to SQL, ie what is in the database.
Probably, I would get the non sorted results with a getResultList(), then manually sort them :
making your EvaluatedValue a type that implements Comparable :
see here