How to check if some column in JDBC table is null in Java

Question

I need to check if a field in my table is empty (null) and if so, do a specific task; if not, do something different. I have tried rs.wasNull() and got the error "wasNull() called with no data retrieved". Are there any other methods to do this?

Answer 1

在调用rs.wasNull()之前，您首先需要从rs获取值，例如使用rs.getInt("col1") rs.wasNull() 。

Answer 2

Another method? rs.wasNull() is the best way. But if you insist... Depending on the implementation of the JDBC driver (varies according to the vendor database), you can do the following:

Object decimalDigits = rs.getObject("DECIMAL_DIGITS");
if (decimalDigits == null) {
    // do something
}