java - Ask a question about spring scheduled tasks

Question

About the scheduled task expression:
0 o'clock every day: 0 0 0 ?
1 o'clock every day: 0 0 1 ?
The above all run at normal time points.
But the other one is not normal. Did I write it wrong?
0:00 on the 1st of every month: 0 0 0 1 * ?
9:00 on the 1st of every month: 0 0 9 1 * ?

Answer 1

For reference only

Answer 2

Is the expression okay? What’s wrong?

Answer 3

Check the quartz related expressions to determine whether the format is correct