Question 1: Why is there a cron expression with 5 arguments

There is a cron expression 0 6 * * * that uses 5 parameters

Cron expressions are divided into six or seven fields, from left to right: second minute hour day month week year Cron expressions & crontab scheduled tasks

Very confused, I searched this link to ask for a crontab time notation – V2EX

Crontab can be written in different ways, with either 5 or 6 parameters, depending on which library you are using

Answered my question. The five parameters are expressed as minute, day, month and week. 0 6 * * * indicates that tasks are executed at 6:00 p.m. every day. The CRon scheduling expression editor displays the expression meaning intuitively

The editor lists the allowable ranges and meanings of each parameter

Cron expression for 5 parameters, see:

Online Crontab expression execution time calculation – code tool

Cron expression parameter description of 6 parameters…

6 – parameter Cron expression editor

For example, 0 */15 * * *? Run this command every 15 minutes.

Question 2: Why does the 6-parameter Cron expression week field 5L represent the Thursday of the last week of the month instead of Friday

CRON expression explanation – Ant Group fintech

The allowed values of the week range from 1 to 7:1 indicates Sunday, 2 indicates Monday, and 5 indicates Thursday