About IDEA using the built-in object methods in java jsp file compilation error solution appears

The red, i.e. the compiled given IDEA

　　

 

 

Reasons, lack Tomcat in a jar, jsp-api.jar and Tomcat servlet-api.jar can be introduced into the lib directory, here introducing step

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 　4, you can only add a jar package, so to add two times, after the addition is complete click OK

　　

 

 　5, add after not being given the success, and the method of the built-in objects will automatically prompt