背景
因需要链表操作，所以采用了@select注解来写sql，抛弃了传统的xml形式。
1.错误性示范代码
@Select({"<script>", "select a.*,b.uuid,b.denoter_name as denoterName,b.spelling,b.public_name as publicName from t_denoter_qrcode a right join t_bz_denoter b on a.denoter_uuid=b.denoter_uuid ", "where 1=1 ", "<if test='qrcodeRequest.denoterAddress !=null and qrcodeRequest.denoterAddress!="" '>" , " and a.address like concat('%',#{qrcodeRequest.denoterAddress},'%')" , "</if> ", "<if test='qrcodeRequest.denoterName !=null and qrcodeRequest.denoterName!="" '>" , " and b.denoter_name like concat('%',#{qrcodeRequest.denoterName},'%') " , "</if> ", "<if test='qrcodeRequest.publicName !=null and qrcodeRequest.publicName!="" '> " , " and b.public_name like concat('%',#{qrcodeRequest.publicName},'%')" , "</if> ", " <if test='qrcodeRequest.xzqhdm !=null and qrcodeRequest.xzqhdm!="" '>" , " and b.zzzz9998 like concat(#{qrcodeRequest.xzqhdm},'%') " , "</if> ", "</script>"}) List<DenoterQrcodeEntity> denoterQueryList(@Param("qrcodeRequest") QrcodeRequest qrcodeRequest);
会报如下错误：
if元素类型必须后跟属性规范、">“或"/>”
这是因为我们在写sql时候没有转义导致的！
2、正确的写法，看仔细哦
@Select({"<script>", "select a.*,b.uuid,b.denoter_name as denoterName,b.spelling,b.public_name as publicName from t_denoter_qrcode a right join t_bz_denoter b on a.denoter_uuid=b.denoter_uuid ", "where 1=1 ", "<if test='qrcodeRequest.denoterAddress !=null and qrcodeRequest.denoterAddress!=\"\" '>" , " and a.address like concat('%',#{qrcodeRequest.denoterAddress},'%')" , "</if> ", "<if test='qrcodeRequest.denoterName !=null and qrcodeRequest.denoterName!=\"\" '>" , " and b.denoter_name like concat('%',#{qrcodeRequest.denoterName},'%') " , "</if> ", "<if test='qrcodeRequest.publicName !=null and qrcodeRequest.publicName!=\"\" '> " , " and b.public_name like concat('%',#{qrcodeRequest.publicName},'%')" , "</if> ", "<if test='qrcodeRequest.xzqhdm !=null and qrcodeRequest.xzqhdm!=\"\" '>" , " and b.zzzz9998 like concat(#{qrcodeRequest.xzqhdm},'%') " , "</if> ", "</script>"}) List<DenoterQrcodeEntity> denoterQueryList(@Param("qrcodeRequest") QrcodeRequest qrcodeRequest);
可以看到上面写法中，在判断空字符串的时候加入了转义，这样就可以解决问题！
