mybatis注意事项

9AMC

---------------------以数组作为查询条件，判断数组大小
<if test="dateList != null and dateList.size() > 0">
        and DATE_FORMAT(tfp.update_time, '%Y-%m-%d') in
        <foreach item="date" index="index" collection="dateList" open="(" separator="," close=")">  
 #{date}  
</foreach> 
</if> 
 
------------------------mybatis字符串比较方法
<if test='deviceStatus != null and deviceStatus != "" and deviceStatus == "0" '>
and (vdm.`status` is null or vdm.`status` = '')
</if>
 
注意单引号和双引号的用法
<if test='deviceStatus != null and deviceStatus != "" and deviceStatus == "0" '>
and (vdm.`status` is null or vdm.`status` = '')
</if>
 
注意单引号和双引号的用法
 
-------------------------------参数数组判断空
　　<if test="deviceIds != null and deviceIds.size() > 0">
　　and t.DEVICE_ID in
　　<foreach item="deviceId" index="index" collection="deviceIds"
　　open="(" separator="," close=")">
　　#{deviceId}
　　</foreach>
　　</if>
　　mybatis存储过程类型定义如下：
　　http://blog.csdn.net/woshixuye/article/details/12953803
　　===Caused by: java.lang.IllegalArgumentException: Result Maps collection does not contain value for integralSQL.hashmap
　　原因：  <select id="selectProductExchangeOrder" resultMap="hashmap" parameterType="hashmap" >
　　应该为  <select id="selectProductExchangeOrder" resultType="hashmap" parameterType="hashmap" >
　　 
　　resultMap 改为 resultType
　　注意：mybatis执行sql检测整个mapper文件的语法，不要只关注你执行的那句sql是不是有语法错误，要看这个mapper文件是不是有语法错误