mybatis莫名报错java.lang.NullPointerException

清疚 2022-04-04 14:54 1030阅读 0赞

今天在使用mybatis和oracle数据库执行操作时，莫名其妙的报错：

严重: Servlet.service() for servlet \[spring\] in context with path \[/crm\] threw exception \[Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException:   
\#\#\# Error querying database.  Cause: java.lang.NullPointerException  
\#\#\# The error may exist in file \[F:\\apache-tomcat-9.0.6\\webapps\\crm\\WEB-INF\\classes\\mapper\\crm\\order\\CrmShopOrderMapper.xml\]  
\#\#\# The error may involve CrmShopOrder.findShopOrderAnalysis  
\#\#\# The error occurred while handling results  
\#\#\# SQL: SELECT    A.ORDER\_NUM,    A.MONTHS,    A.PRODUCTCODE,    A.PRODUCTNAME,    A.CATEGORY\_NAME,    A.TOTALAMOUNT,    B.TOTALAMOUNT\_SUM,    B.ORDER\_NUM\_COUNT   FROM   (    SELECT      COUNT(A.MERGE\_CODE) ORDER\_NUM,     TO\_CHAR(A.CREATED\_TIME,'MM') MONTHS,     B.PRODUCTCODE,     B.PRODUCTNAME,     D.CATEGORY\_NAME,     A.TOTALAMOUNT    FROM MALL\_ORDER A     LEFT JOIN MALL\_ORDER\_PRODUCT B ON B.ORDER\_ID = A.ID    LEFT JOIN MALL\_PRODUCT C ON C.ID = B.PRODUCT\_ID    LEFT JOIN MALL\_CATEGORY D ON D.ID = C.MALLCATEGORY\_ID    WHERE              A.CREATED\_TIME BETWEEN TO\_DATE(?, 'yyyy-mm-dd hh24:mi:ss') AND TO\_DATE(?, 'yyyy-mm-dd hh24:mi:ss') AND A.STATUS = 1            GROUP BY A.CREATED\_TIME,B.PRODUCTCODE,A.TOTALAMOUNT,B.PRODUCTNAME,D.CATEGORY\_NAME   ) A   LEFT JOIN   (    SELECT     SUM(TOTALAMOUNT) TOTALAMOUNT\_SUM,     COUNT(ORDER\_NUM) ORDER\_NUM\_COUNT,     A.MONTHS    FROM    (     SELECT       COUNT(A.MERGE\_CODE) ORDER\_NUM,      TO\_CHAR(A.CREATED\_TIME,'MM') MONTHS,      B.PRODUCTCODE PRODUCTCODE,      B.PRODUCTNAME PRODUCTNAME,      D.CATEGORY\_NAME CATEGORY\_NAME,      A.TOTALAMOUNT TOTALAMOUNT     FROM MALL\_ORDER A      LEFT JOIN MALL\_ORDER\_PRODUCT B ON B.ORDER\_ID = A.ID     LEFT JOIN MALL\_PRODUCT C ON C.ID = B.PRODUCT\_ID     LEFT JOIN MALL\_CATEGORY D ON D.ID = C.MALLCATEGORY\_ID     WHERE               A.CREATED\_TIME BETWEEN TO\_DATE(?, 'yyyy-mm-dd hh24:mi:ss') AND TO\_DATE(?, 'yyyy-mm-dd hh24:mi:ss') AND A.STATUS = 1             GROUP BY A.CREATED\_TIME,B.PRODUCTCODE,A.TOTALAMOU

经过排查，发现有一个数据库字段是DOUBLE类型，而mybatis的select语句中参数类型和结果类型都是map，不是返回实体，由于数据库底层的原因会导出报错NullPointerException。

解决方法：在sql语句中对DOUBLE类型的字段进行类型转换，转换为number类型；或者修改数据库该字段的类型为number类型