标签：如何 报错 span date parent tao dao ati star
@Mapper public interface DemandCommentMapper extends BaseMapper<DemandComment>{ @Select("SELECT " + "a.id as ‘id‘,a.create_date as ‘createDate‘,a.content as ‘content‘," + "a.parent_id as ‘parentId‘,a.first_comment_id as ‘firstCommentId‘," + "b.id as ‘fromUser.id‘,b.realname as ‘fromUser.realname‘,b.avatar as ‘fromUser.avatar‘," + "c.id as ‘toUser.id‘,c.realname as ‘toUser.realname‘,c.avatar as ‘toUser.avatar‘ " + "FROM t_demand_comment a " + "LEFT JOIN t_user b ON b.id = a.from_uid " + "LEFT JOIN t_user c ON c.id = a.to_uid " + "WHERE a.demand_id = #{demandId} " + "ORDER BY a.create_date ASC" + "LIMIT #{startNo},#{pageSize}") public List<DemandComment> listDemandComment(@Param("demandId") Long demandId,
@Param("startNo") Integer pageNo,
@Param("pageSize") Integer pageSize);
这样整个语句是写死的，如果我想根据pageNo与pageSize是否为空来判断是否需要分页，该怎么做呢?
如果使用xml来配置的话可以用
<when test=‘startNo!=null and pageSize != null ‘>
LIMIT #{startNo},#{pageSize}
</when>
如果是用@Select 这种该如何做呢？
方法：用script标签包围，然后像xml语法一样书写
@Mapper public interface DemandCommentMapper extends BaseMapper<DemandComment>{ @Select("<script>" + "SELECT " + "a.id as ‘id‘,a.create_date as ‘createDate‘,a.content as ‘content‘," + "a.parent_id as ‘parentId‘,a.first_comment_id as ‘firstCommentId‘," + "b.id as ‘fromUser.id‘,b.realname as ‘fromUser.realname‘,b.avatar as ‘fromUser.avatar‘," + "c.id as ‘toUser.id‘,c.realname as ‘toUser.realname‘,c.avatar as ‘toUser.avatar‘ " + "FROM t_demand_comment a " + "LEFT JOIN t_user b ON b.id = a.from_uid " + "LEFT JOIN t_user c ON c.id = a.to_uid " + "WHERE a.demand_id = #{demandId} " + "ORDER BY a.create_date ASC " + "<if test=‘startNo!=null and pageSize != null ‘>" + "LIMIT #{startNo},#{pageSize}" + "</if>" + "</script>") public List<DemandComment> listDemandComment(@Param("demandId") Long demandId,
@Param("startNo") Integer pageNo,
@Param("pageSize") Integer pageSize);
项目实例
@Select("<script>"
+"select * from mi_taobao where 1=1"
+"<if test=‘status != null‘>"
+"and status = #{status}"
+"</if>"
+"</script>")
public List<Taobao> getTaobao(@Param("status") Integer status);
在这里还碰到一个问题就是报错：Caused by: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named ‘status‘ in ‘class java.lang.Interger‘
出现原因：这里出现的问题是在DAO方法中定义的参数 与 实体中定义的属性不一致 导致的。
解决方案：dao层加@Param("userId")注解即可（实例中就是加上@Param("status")）
public List<DictItem> selectKeyByUserId(@Param("userId") long userId);
标签：如何 报错 span date parent tao dao ati star
原文地址：https://www.cnblogs.com/goloving/p/9241421.html
