HTTP Methods
GET: designed for getting information (a document, a chart, or the results from a database query).
POST:designed for posting information (a credit card number, some new chart data, or information that is to be stored in a database).
PUT: to place documents directly on the server.
DELETE:to delete documents directly on the server.
HEAD:sent by a client when it wants to see only the headers of the response, to determine the document's size, modification time, or general availability
OPTION:to be used to ask the server which methods it supports or what options are available for a particular resource on the server.
TRACE:to be used as a debugging aid—it returns to the client the exact contents of its request.
其中最后两种很少用到.