mybatis 參數爲Integer型數據並賦值0時，0被當作空處理，解決及緣由

mybatis 參數爲Integer型數據並賦值0時，0被當作空處理：

mybatis.xml中有if判斷條件判斷參數不爲空時，賦值爲0的Integer參數被mybatis判斷爲空， 不執行<if test="param != null and param != ''"></if>的sql。

解決方法： 判斷非空改成：<if test="param != null"</if>

用到mybatis時，避免用0來作值

官方解釋： https://commons.apache.org/proper/commons-ognl/language-guide.html

Interpreting Objects as Booleans Any object can be used where a boolean is required. OGNL interprets objects as booleans like this: If the object is a Boolean, its value is extracted and returned; If the object is a Number, its double-precision floating-point value is compared with zero; non-zero is treated as true, zero as false; If the object is a Character, its boolean value is true if and only if its char value is non-zero; Otherwise, its boolean value is true if and only if it is non-null.