＜if test=“state!=null and state==‘0‘ “＞ mybatis中使用if test判断参数值得问题

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本文探讨了在MyBatis中正确使用条件判断的方法，强调了在OGNL表达式中应使用双引号或toString()进行字符串比较，避免因类型不匹配导致的逻辑错误。

记录一个使用mybatis中的小问题

使用
当条件中有判断值是, 要是用 ==,而不能使用单个 =,
mybatis是用OGNL表达式来解析的，在OGNL的表达式中，’1’会被解析成字符，java是强类型的，char 和一个string 会导致不等，所以if标签中的sql不会被解析。
总结下使用方法：单个的字符要写到双引号里面或者使用.toString()才行！

以下为错误示范:

     <if test="customerState!=null and customerState= '1' ">
        and rc.user_id is not null
    </if>
    <if test="customerState!=null and customerState='2'">
        and rc.name_tags_dcount is not null
    </if>
    <if test="customerState!=null and customerState='3'">
        and rc.name_tags_scount is not null
    </if>
    <if test="customerState!=null and customerState='4'">
        and rc.status = '7'
    </if>
    <if test="customerState!=null and customerState='5'">
        and rc.status = '11'
    </if>

查看打印出的sql
WHERE
1 = 1
AND rc.shareId = ?
AND rc.user_id IS NOT NULL
AND rc.name_tags_dcount IS NOT NULL
AND rc.name_tags_scount IS NOT NULL
AND rc.STATUS = ‘7’
AND rc.STATUS = ‘11’
很明显这不是我想要的, 修改一下

	<if test="customerState!=null and customerState== '1'.toString()">
        and rc.user_id is not null
    </if>
    <if test="customerState!=null and customerState=='2'.toString()">
        and rc.name_tags_dcount is not null
    </if>
    <if test="customerState!=null and customerState=='3'.toString()">
        and rc.name_tags_scount is not null
    </if>
    <if test="customerState!=null and customerState=='4'.toString()">
        and rc.status = '7'
    </if>
    <if test="customerState!=null and customerState=='5'.toString()">
        and rc.status = '11'
    </if>

控制台打印sql为

FROM
	room_clues rc
	LEFT JOIN cloud_user cu ON cu.id = rc.user_id
	LEFT JOIN cartype ct ON ct.id = rc.carTypeId
	LEFT JOIN cartype ct1 ON ct1.id = rc.deal_car_type_id 
WHERE
	1 = 1 
	AND rc.shareId = ?