Revert "Revert "将参数写成常数，便于以后修改""

This reverts commit ec1c9d7fc9bf7cc2488f5589509fe4ce8cc4561b.

Revert "将参数写成常数，便于以后修改"

This reverts commit
f6cf6a7217e312bee887360574578f6c507cc482.
Revert "Revert "Revert "将参数写成常数，便于以后修改"""

This reverts commit 62b2525c2dd1fbc60cadef303bd86ded347c6ca4.