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  • Mybatis动态插入数据(使用trim标签)

    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>

        &lt;trim prefix=<span class="hljs-string">"values ("</span> suffix=<span class="hljs-string">")"</span> suffixOverrides=<span class="hljs-string">","</span> &gt;</br>
          #{id, jdbcType=VARCHAR},</br>
          #{memberId, jdbcType=VARCHAR},</br>
          &lt;<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> '&gt;</br>
            #{messageClassify, jdbcType=VARCHAR},</br>
          &lt;/<span class="hljs-keyword">if</span>&gt;</br>
          &lt;<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> '&gt;</br>
            #{messageCode, jdbcType=VARCHAR},</br>
          &lt;/<span class="hljs-keyword">if</span>&gt;</br>
          &lt;<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> '&gt;</br>
            #{messageContent, jdbcType=VARCHAR},</br>
          &lt;/<span class="hljs-keyword">if</span>&gt;</br>
        &lt;/trim&gt;  </br>
    

    </insert>

    trim标签的属性

    1. prefix:前缀覆盖并增加其内容。也就是给中的sql语句加上前缀;
    2. suffix:后缀覆盖并增加其内容。给包裹的sql语句加上后缀;
    3. prefixOverrides:前缀判断的条件。取消指定的前缀,如where;
    4. suffixOverrides:后缀判断的条件。取消指定的后缀,如and | or.,逗号等。

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  • 原文地址:https://www.cnblogs.com/jpfss/p/8920650.html
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