如何檢查DATE數據類型中的空指針異常

Question

我們有Talend數據集成工具，該工具在將信息從源發送到目標系統時使用蝕代碼。 遇到錯誤

Exception in component tMap_1

    java.lang.NullPointerException
        at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.tJDBCInput_2Process(Copy_of_ReadSysproAndSendMail.java:1937)
        at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.runJobInTOS(Copy_of_ReadSysproAndSendMail.java:5086)
        at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.main(Copy_of_ReadSysproAndSendMail.java:4885)

        at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.tJDBCInput_2Process(Copy_of_ReadSysproAndSendMail.java:2098)
    at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.runJobInTOS(Copy_of_ReadSysproAndSendMail.java:5355)
    at bigdata.copy_of_readsysproandsendmail_0_1.Copy_of_ReadSysproAndSendMail.main(Copy_of_ReadSysproAndSendMail.java:5154)
Job Copy_of_ReadSysproAndSendMail ended at 23:16 03/10/2016. [exit code=0]

輸入：

日期數據類型是tmap組件中空值的來源

DNDB date type(source) ---->row1.DNDB(output) is Date data type. both are nullable.

我們嘗試過：但是對我們沒有用。

避免為空
row1.DNDB == null？“ null”：row1.DNDB

Answer 1

row1.DNDB==null?"null":row1.DNDB無法工作：您正在為輸出值分配“ null”（帶雙引號的字符串）或row1.DNDB，該日期應為日期。 您將在編譯中出現強制轉換異常。

您可以嘗試：

Relational.ISNULL(row1.DNDB)?null:row1.DNDB

如果你要一個Date返回類型; 要么

Relational.ISNULL(row1.DNDB)?"null":TalendDate.formatDate("yyyy-MM-dd HH:mm:ss",row1.DNDB) 

如果您想要兩個值的String返回類型。

還要檢查您的輸出列是否標記為可空（復選框）