如何从 javax.persistence.Query 获取查询字符串？

Question

Maybe I am missing something, but I simply want to (in my java program) get the query string from a javax.persistence.Query object? The Query object itself doesn't seem to have a method to do that. Also I know that our manager doesn't want us to use Spring framework stuff (for example using their QueryUtils class).

Is there not a way to simply get the query string from javax.persistence.Query object (Again, in a java program)?!

Answer 1

There is no JPA-standard way, but some implementations have their own methods. For example DataNucleus JPA allows you to do

query.toString();

Look at the docs of your implementation for how they do it. See also this blog entry http://antoniogoncalves.org/2012/05/24/how-to-get-the-jpqlsql-string-from-a-criteriaquery-in-jpa/

Answer 2

There is no standard way in JPA,

If you are using EclipseLink see,

http://wiki.eclipse.org/EclipseLink/FAQ/JPA#How_to_get_the_SQL_for_a_Query.3F

Answer 3

no problem. hibernate:

query.unwrap(org.hibernate.Query.class).getQueryString()

or eclipselink

query.unwrap(JpaQuery.class).getDatabaseQuery().getJPQLString(); // doesn't work for CriteriaQuery query.unwrap(JpaQuery.class).getDatabaseQuery().getSQLString();

or open JPA

query.unwrap(org.apache.openjpa.persistence.QueryImpl.class).getQueryString()

...you get the idea....

Answer 4

Using OpenJPA I was able to do this:

OpenJPAQuery<MyEntity> q = (OpenJPAQuery<MyEntity>) query;
String mySQL = q.getQueryString();

The cast to OpenJPAQuery is important because the Query interface does not have the method getQueryString() on it.

The stored parameters are not filled in unfortunately but I'm working on figuring out how to do that myself.

Answer 5

Edit your persistence properties file if JPA is provided by hibernate. Add the below section -

<property name="hibernate.show_sql" value="true"/>