Mybatis动态插入数据(使用trim标签)
有时我们控制同一张表,但传入的参数不固定,操作表的字段不固定,就要用到mybatis动态插入。.xml如下:
<insert id="insertMessage" parameterType="com.sf.ccsp.member.client.request.MessageReq">
insert cx_customer_message
(ID,MEMBERID,
<if test='messageClassify != null and messageClassify != "" '>
MESSAGEE_CLASSIFY,
</if>
<if test='messageCode != null and messageCode != "" '>
MESSAGE_CODE,
</if>
<if test='messageContent != null and messageContent != "" '>
MESSAGE_CONTENT
</if>
)
values (
#{id, jdbcType=VARCHAR},
#{memberId, jdbcType=VARCHAR},
<if test='messageClassify != null and messageClassify != "" '>
#{messageClassify, jdbcType=VARCHAR},
</if>
<if test='messageCode != null and messageCode != "" '>
#{messageCode, jdbcType=VARCHAR},
</if>
<if test='messageContent != null and messageContent != "" '>
#{messageContent, jdbcType=VARCHAR}
</if>
)
</insert>
问题来了,当messageClassify !=null,但messageCode 和messageContent 为空时,会多出来逗号,以至于mybatis报错。正确的用法如下.xml:
<insert id="insertMessage" parameterType="com.sf.ccsp.member.client.request.MessageReq">
insert cx_customer_message
<trim prefix="(" suffix=")" suffixOverrides="," >
ID,MEMBERID,
<if test='messageClassify != null and messageClassify != "" '>
MESSAGEE_CLASSIFY,
</if>
<if test='messageCode != null and messageCode != "" '>
MESSAGE_CODE,
</if>
<if test='messageContent != null and messageContent != "" '>
MESSAGE_CONTENT,
</if>
</trim>
<trim prefix=<span class="hljs-string">"values ("</span> suffix=<span class="hljs-string">")"</span> suffixOverrides=<span class="hljs-string">","</span> ></br>
#{id, jdbcType=VARCHAR},</br>
#{memberId, jdbcType=VARCHAR},</br>
<<span class="hljs-keyword">if</span> test='messageClassify != <span class="hljs-keyword">null</span> <span class="hljs-keyword">and</span> messageClassify != <span class="hljs-string">""</span> '></br>
#{messageClassify, jdbcType=VARCHAR},</br>
</<span class="hljs-keyword">if</span>></br>
<<span class="hljs-keyword">if</span> test='messageCode != <span class="hljs-keyword">null</span> <span class="hljs-keyword">and</span> messageCode != <span class="hljs-string">""</span> '></br>
#{messageCode, jdbcType=VARCHAR},</br>
</<span class="hljs-keyword">if</span>></br>
<<span class="hljs-keyword">if</span> test='messageContent != <span class="hljs-keyword">null</span> <span class="hljs-keyword">and</span> messageContent != <span class="hljs-string">""</span> '></br>
#{messageContent, jdbcType=VARCHAR},</br>
</<span class="hljs-keyword">if</span>></br>
</trim> </br>
</insert>
trim标签的属性
- prefix:前缀覆盖并增加其内容。也就是给中的sql语句加上前缀;
- suffix:后缀覆盖并增加其内容。给包裹的sql语句加上后缀;
- prefixOverrides:前缀判断的条件。取消指定的前缀,如where;
- suffixOverrides:后缀判断的条件。取消指定的后缀,如and | or.,逗号等。