JDBC在eclipse中给出了很多错误

Question

As you see there's a lot of errors in the project! However, the program runs well :) but I want to remove this errors or at least know its reason

Answer 1

In Eclipse you have the Problems tab available on one of the panes, this should list the reasons for all the errors in your screenshot. You need to look at that list which will explain why each error is present and then investigate them from there.

"To add the Problems view to the current perspective, Window > Show View > Other... > General > Problems."

Answer 2

I think you extracted the jar file from mysql driver and then imported the extracted files into the project. Instead, create a new project and add the jar in the project and add them later in the build path of the project.

See it: http://www.wikihow.com/Add-JARs-to-Project-Build-Paths-in-Eclipse-(Java)