You can add an Area2D to a spring sprite. And use the on Body entered signal
After you connect it. It should create a function on your object script( this will work if you have a script connected to the player, and you only want one thing to jump)
A function will be created called:
Inside this you can use
get_position to get the objects position.
Before anyone can help you further we need more info what is the spring going to be used for is it for a pinball machine. To help the player jump to platforms. What kind of physics is the player using.
When asking for help always be specific, as people's help is limited to how specific you are.