Mybatis动态更新数据

Mybatis动态更新数据

原理同上一篇的 Mybatis动态插入数据（使用trim标签） ，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动态更新，普通的<if test=" ">的方法会出现多余的字符。

方法一：使用set标签

 <update id="updateMessage"  parameterType="com.sf.ccsp.member.client.request.MessageReq" >
     update cx_customer_message
     <set>
        <if test='messageClassify != null and messageClassify != "" '>
          MESSAGEE_CLASSIFY = #{messageClassify, jdbcType=VARCHAR},
        </if>
        <if test='messageCode != null and messageCode != "" '>
          MESSAGE_CODE = #{messageCode, jdbcType=VARCHAR},
        </if>
        <if test='messageContent != null and messageContent != "" '>
          MESSAGE_CONTENT = #{messageContent, jdbcType=VARCHAR},
        </if>
     </set>
     where ID = #{id, jdbcType=VARCHAR}
     and MEMBERID = #{memberId, jdbcType=VARCHAR} 
</update>

方法二：使用trim标签

<update id="updateMessage"  parameterType="com.sf.ccsp.member.client.request.MessageReq" >
     update cx_customer_message
     <trim prefix="set" suffixOverrides=",">  
        <if test='messageClassify != null and messageClassify != "" '>
          MESSAGEE_CLASSIFY = #{messageClassify, jdbcType=VARCHAR},
        </if>
        <if test='messageCode != null and messageCode != "" '>
          MESSAGE_CODE = #{messageCode, jdbcType=VARCHAR},
        </if>
        <if test='messageContent != null and messageContent != "" '>
          MESSAGE_CONTENT = #{messageContent, jdbcType=VARCHAR},
        </if>    
     </trim>  
     where ID = #{id, jdbcType=VARCHAR}
     and MEMBERID = #{memberId, jdbcType=VARCHAR} 
</update>