MyBatis動態插入的實現

mybatis通過定義前綴后綴和分割字符來拼接sql語句，實現動態插入的功能

<insert id="addNewsTypeByNewsId">
        insert into news_newstype

        <trim prefix="(" suffix=")" suffixOverrides=",">
            <if test="newsId != null">
                newsid,
            </if>
            <if test="newsTypeId != null and newsTypeId !=0">
                newstypeid,
            </if>
        </trim>
        <trim prefix="values (" suffix=")" suffixOverrides=",">
            <if test="newsId != null">
                #{newsId},
            </if>
            <if test="newsTypeId != null and newsTypeId !=0">
                #{newsTypeId},
            </if>
        </trim>
    </insert>