First on the map:
.idea catalog:
This directory is automatically IDEA project generated directory, major record some historical information, version information about the projects, or backtrack in order to facilitate future restoration projects, will not affect the operation of the project.
out catalog:
This directory is a directory deployment projects, visit our page in the browser that files in this directory. This directory is the idea to help us automatically generated.
src directory:
Store the java code written.
web:
You need to deploy to the file server.
iml file:
Yes Project ID file, this file is missing, IDEA project can not be identified. Eclipse .project file with nature is the same. And content on different devices these files will vary, so when we manage projects, .project and .iml files need to be ignored.