NIFI-15305 Fix Date Time conversion for floating point as string

[exceptionfactory]

Summary

NIFI-15305 Corrects String to LocalDateTime conversion for floating point numbers represented as strings.

The current implementation checks long numbers for values larger than the year 10,000, but does not implement a similar check for floating point numbers represented as strings.

The corrected approach checks the integral part of a floating point number for values larger than the year 10,000 in seconds, and then handles the number as epoch milliseconds. The parsing strategy also handles the fractional part as either the number of microseconds or the number of milliseconds.

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  • JDK 21
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