The config.json file describes many important settings for this program, such as email, sql server, username, password, etc. 

The "tasks" section includes all actual tasks that need to be executed automatically. The number of tasks is unlimited, and task itself can be customized separately. For a task, it can have following properties(If you choose not to provide these properties, it will try the default properties, which are defined in root level):

[task]
"sender" - email sender for this task, if not provided, it's value is the same as upper level.
"mailpass" - email password, if not provided , the same with upper level.
"cc" - ...
"bcc" - ...
"dbconn - database connection string. It can support all kinds of database, be it mysql, oracle or sql server, as long as you provide the correct connection string.

the unique properties of task are:
"period" - It tells the program when to execute this task. There are different types of "period", such as daily, weekly, monthly, yearly, here are some examples:
"period":"daily, 19:30:00"
"period":"weekly, 1, 19:30:00"
"period":"monthly, 1, 19:30:00"
"period":"yearly, 0501, 19:30:00"
The meanings are: "everyday 7:30pm", "every monday 7:30pm", "the first day of every month, 7:30pm", "every year, May 1st, 7:30pm". Note, for weekly, 1 to 6 stands for Monday to Saturday, 7 is Sunday. 
To make it work, the rule has to be strickly followed.

"enabled" - If you want to temporarily disabled a specific task, assign "false" value to it. By default, if this value is not provided, it will be given a "true"


"excel" - The name of the generated excel file. For example, if it is defined as "FundTrans", the final file name would be "FundTrans-daily-19:30:00.xslx", the tail part is added to indicate the time and type of this file. 

"sheets" - you can decide how many sheets in the file can have
"sheets -> name" - name of the sheet
"sheets -> sql" - It is the name of the sql file resides in sql directory.


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valid paper size:
PAPERSIZE_A3, PAPERSIZE_A4, PAPERSIZE_A4_SMALL, PAPERSIZE_A5, PAPERSIZE_EXECUTIVE, PAPERSIZE_LEDGER, PAPERSIZE_LEGAL, PAPERSIZE_LETTER, PAPERSIZE_LETTER_SMALL, PAPERSIZE_TABLOID