How does mybatis call mysql stored procedure and get the return value

mybatis calls mysql stored procedure and gets the return value

1, mysql creates stored procedure

#结束符号默认;, delimiter $$语句表示结束符号变更为$$ delimiter $$ CREATE PROCEDURE `demo`(IN inStr VARCHAR(100), out ourStr VARCHAR(4000)) BEGIN SET ourStr = '01'; if (inStr == '02') then set ourStr = '02'; end if; END$$ #结束符号修改 delimiter ;

2, mybatis calls

(1) Annotation method

// key1和key2都是参数map中的key // key1是需要传入存储过程的值 // key2是用于接收存储过程返回的值，跟获取自增主键类似 @Select("call demo('${key1}', #{key2, mode=OUT, jdbcType=VARCHAR})") @Options(statementType = StatementType.CALLABLE) String getDemoValue(Map map);

(2)xml method

 call demo('${key1}', #{key2, mode=OUT, jdbcType=VARCHAR}) 

Mybatis encounters the pitfall of returning a null value when calling a stored procedure

Mybatis returns a null value when calling a stored procedure

It’s a simple one Stored procedure

BEGIN #SELECT COUNT(*) scount FROM test_user t WHERE t.user_sex=sex; SELECT user_name userName FROM test_user t WHERE t.user_sex=sex; END

Then in the Mybatis Mapper configuration file

  { CALL queryCountBySexWithProcedure( #{sex,jdbcType=VARCHAR,mode=IN}, #{userName,jdbcType=VARCHAR,mode=OUT} ) } 

then the userName value is null. Why is this? Mapping is performed in the mapper.xml file, and the attribute user_name marked in red below in the stored procedure is not automatically mapped to the userName value, so calling the userName value must return null.

BEGIN #SELECT COUNT(*) scount FROM test_user t WHERE t.user_sex=sex; SELECT user_name userName FROM test_user t WHERE t.user_sex=sex; END

So how to deal with this problem? That is to add the INTO keyword

BEGIN #SELECT COUNT(*) scount FROM test_user t WHERE t.user_sex=sex; SELECT user_name INTO userName FROM test_user t WHERE t.user_sex=sex; END

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