考虑到您有一个输出基本类型的简单存储过程:
CREATE PROCEDURE count_comments (
IN postId INT,
OUT commentCount INT
)
BEGIN
SELECT COUNT(*) INTO commentCount
FROM post_comment
WHERE post_comment.post_id = postId;
END
您可以使用 JPA 调用此存储过程StoredProcedureQuery
:
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");
如果您的存储过程返回 aREFCURSOR
或TABLE
结果:
CREATE PROCEDURE post_comments(IN postId INT)
BEGIN
SELECT *
FROM post_comment
WHERE post_id = postId;
END
您需要按如下方式调用存储过程:
StoredProcedureQuery query = entityManager
.createStoredProcedureQuery("post_comments");
query.registerStoredProcedureParameter(1, Long.class, ParameterMode.IN);
query.setParameter(1, 1L);
List<Object[]> postComments = query.getResultList();
对于数据库函数,返回结果集而不是将其放入OUT
变量中:
CREATE FUNCTION fn_count_comments(postId integer)
RETURNS integer
DETERMINISTIC
READS SQL DATA
BEGIN
DECLARE commentCount integer;
SELECT COUNT(*) INTO commentCount
FROM post_comment
WHERE post_comment.post_id = postId;
RETURN commentCount;
END
Hibernate 4.x 和 5.x API 对您没有帮助,您必须改用 JDBC:
int commentCount = session.doReturningWork(connection -> {
try (CallableStatement function = connection.prepareCall(
"{ ? = call fn_count_comments(?) }")) {
function.registerOutParameter(1, Types.INTEGER);
function.setInt(2, 1);
function.execute();
return function.getInt(1);
}
});