mybatis的动态sql写到java文件中

最新推荐文章于 2024-04-26 04:00:00 发布

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本文探讨了如何将MyBatis中的动态SQL语句移到Java文件中，以此来提高代码的可读性和维护性。通过实例展示了动态SQL的结构和实现方式。

动态sql结构

import org.apache.ibatis.annotations.Select;

//查询
@Select({"<script>",
            SQL字符串,
            "</script>"
    })
List<Article> getArticlePaged(ReqPara reqPara);




import org.apache.ibatis.annotations.Update;

//修改、删除(逻辑删也是编辑)
@Update({"<script>",
            SQL字符串,
            "</script>"
    })
int editArticle(Article article);

SQL字符串内可以拼接动态sql

举例

 String QUERY_SQL = "select   " +
            "  t.id  AS  id  ,  " +
            "  t.title  AS  title , " +
            "  t.date  AS  date "  ;

    String TABLE_JOIN_SQL = " from article t ";

    String QUERY_WHERE_SQL = " where 1=1  " +
            "<if test='title!=null and title!=\"\"'>" +
            " AND t.title= #{title} " +
            "</if>" +
            "<if test='id!=null and id!=\"\" '>" +
            " AND t.id = #{id} " +
            "</if>" +
            "<if test='dateStart!=null and dateStart!=\"\" '>" +
            " AND t.date &gt;= STR_TO_DATE(#{dateStart}, '%Y-%m-%d %H:%i:%s') " +
            "</if>" +
            "<if test='dateEnd!=null and dateEnd!=\"\" '>" +
            " AND t.date &lt;= STR_TO_DATE(#{dateEnd}, '%Y-%m-%d %H:%i:%s') " +
            "</if>" ;

    String ORDER_BY_SQL = " order by t.date DESC ";

    String LIMIT_SQL = " LIMIT #{pageBeginIndex},#{pageSize} ";


    @Select({"<script>",
            QUERY_SQL,
            TABLE_JOIN_SQL,
            QUERY_WHERE_SQL,
            ORDER_BY_SQL,
            LIMIT_SQL,
            "</script>"
    })
    List<Article> getArticlePaged(ReqPara reqPara);