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This article mainly introduces how to do the test statement failure in mybatis, which has certain reference value. Interested friends can refer to it. I hope you will gain a lot after reading this article. Let Xiaobian take you to understand it together.

mybatis test statement invalid

Under normal circumstances, when writing if test or when test statements of dynamic sql, the conditional quotation is double quotation marks and single quotation marks.

As follows:

select * from tb_user and user = #{user} and passwd = #{passwd} and 1 = 1

But today we found a problem where sql invalidation is not executed when the value passed is 0 or 1.

As follows:

and user = #{user}

After that, it was found that MyBatis itself parsed the problem. In the content of the label, MyBatis was parsed using the OGNL expression. Note that in this place, if there is a character in the single quotation mark, OGNL will parse it as char type in java. At this time, the char type and the parameter String type are compared with equal signs. The result is false.

The solution is simple.

It is to enclose the single character in test in double quotes.

Mybatis test judgment considerations

When using mybatis to make a judgment, be sure to pay attention to whether the incoming data type is consistent with the target value type of the judgment.

During a recent development,

The following is an example of an example of an integer passed in. and a.c_appType = #{appType}

where appType is an integer data. You can see that appType != is used in the test judgment. ''。

During the business function test, it was found that when the value passed in was 0, the conditional filter did not work. Through debugging, it was found that mybatis would convert the empty string to 0.0 of double type.

As shown below:

integer data is also converted to double

As shown below:

So, mybatis determines that the number 0 and the empty string are equal, and our if determines that the two are not equal.

Therefore, when using mybatis to judge, be sure to pay attention to whether the type is consistent, and do not judge the case of empty strings for numeric types.

Thank you for reading this article carefully. I hope that the article "How to do if the test statement in mybatis fails" shared by Xiaobian will help everyone. At the same time, I hope that everyone will support you a lot and pay attention to the industry information channel. More relevant knowledge is waiting for you to learn!

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