如何使用 Hibernate 调用 PostgreSQL 存储过程

Question

I want to create a Stored Procedure in PostgreSQL to make some calculation and return it to My java call. I have tried Most of the option from Java-Hibernate but not able to succeed. Below is my SP.

CREATE OR REPLACE FUNCTION "GET_REPORT"()
RETURNS refcursor AS
$BODY$DECLARE
      ref refcursor; 
BEGIN
OPEN ref FOR Select sum(balance),avg(balance) from sales;
RETURN ref;
END$BODY$
LANGUAGE plpgsql VOLATILE
COST 100;
ALTER FUNCTION "GET_REPORT"()
OWNER TO postgres;

In Java How to call this procedure to get the values. NOTE: I'm not using hibernate XML files to call quires.

Please provide Java code(using Session) and any changes in procedure (if required).

Answer 1

You can use JPA StoredProcedureQuery for calling PostgreSQL stored procedures or functions

StoredProcedureQuery query = entityManager
    .createStoredProcedureQuery("count_comments")
    .registerStoredProcedureParameter("postId", 
        Long.class, ParameterMode.IN)
    .registerStoredProcedureParameter("commentCount", 
        Long.class, ParameterMode.OUT)
    .setParameter("postId", 1L);
 
query.execute();
 
Long commentCount = (Long) query
    .getOutputParameterValue("commentCount");

Or, if you want to use the Hibernate Session :

ProcedureCall call = session
    .createStoredProcedureCall("post_comments");
 
call.registerParameter(1, 
    void.class, ParameterMode.REF_CURSOR);
call.registerParameter(2, 
    Long.class, ParameterMode.IN).bindValue(1L);
 
Output output = call.getOutputs().getCurrent();
 
if (output.isResultSet()) {
    List<Object[]> postComments = 
        ((ResultSetOutput) output).getResultList();
    assertEquals(2, postComments.size());
}

That's it!