MyBatis--11-- 判断 Integer类型,值为0动态SQL不生效
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MyBatis标签: Integer类型,值为0动态SQL不生效
1.现象
status
tinyint(4) DEFAULT ‘0’ COMMENT ‘处理状态:0未处理 1已处理’
<select id="selectDtoList">
SELECT
id,
channel_id AS channelId,
channel_name AS channelName,
group_name AS groupName,
phone AS phone,
ehr_no AS ehrNo,
opinion_content AS opinionContent,
create_time AS createTime,
status AS status,
handle_time AS handleTime
FROM
t_opinion_record
WHERE 1 = 1
<if test="dto.status != null and dto.status != ''">
AND `status` = #{dto.status}
</if>
<if test="dto.startTime != null and dto.startTime != ''">
AND `create_time` >= #{dto.startTime}
</if>
<if test="dto.endTime != null and dto.endTime != ''">
AND `create_time` <= #{dto.endTime}
</if>
ORDER BY create_time DESC
</select>
情况 1:status =1 时 或者其他值时,程序正常拼接sql
情况 2:status =0 时,程序不拼接 ,动态SQL不生效
2.分析原因
Mbatis源码
- 再看org.apache.ibatis.scripting.xmltags.ExpressionEvaluator:evaluateBoolean 这个方法、我们看到了如果是number类型、会与0做判断比较
public boolean evaluateBoolean(String expression, Object parameterObject) {
Object value = OgnlCache.getValue(expression, parameterObject);if (value instanceof Boolean) return (Boolean) value;if (value instanceof Number) return !new BigDecimal(String.valueOf(value)).equals(BigDecimal.ZERO);return value != null;
}
由此可以发现、当动态sql参数是int类型、并且传入0时、是使用OgnlCache获取的value、而OgnlCache是对OGNL的封装
在OGNL的官网上面可以看到如下解释
任何需要布尔值的对象都可以使用。OGNL将对象解释为布尔值,如下所示:
·如果对象是布尔值,则提取并返回其值;
·如果对象是Number,则将其双精度浮点值与零进行比较;非零视为真,零视为假;
·如果对象是Character,则其布尔值为true,当且仅当其char值为非零时;
否则,它的布尔值为true,当且仅当它不是null时。
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.
3.解决办法
去掉判断条件 dto.status != ‘’"即可
<select id="selectDtoList">
SELECT
id,
channel_id AS channelId,
channel_name AS channelName,
group_name AS groupName,
phone AS phone,
ehr_no AS ehrNo,
opinion_content AS opinionContent,
create_time AS createTime,
status AS status,
handle_time AS handleTime
FROM
t_opinion_record
WHERE 1 = 1
<if test="dto.status != null ">
AND `status` = #{dto.status}
</if>
<if test="dto.startTime != null and dto.startTime != ''">
AND `create_time` >= #{dto.startTime}
</if>
<if test="dto.endTime != null and dto.endTime != ''">
AND `create_time` <= #{dto.endTime}
</if>
ORDER BY create_time DESC
</select>
测试结果都正常
原文地址:https://blog.csdn.net/weixin_48052161/article/details/140666409
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