Handling the Client Request: 

Form Data

Example URL at online travel agent

http://host/path?user=Marty+Hall&origin=iad&dest=nrt

Names (user) come from HTML author; 

values (Marty+Hall) usually come from end user

Parsing form (query) data in traditional CGI

Read the data one way for GET requests, another way for 

POST requests

Chop pairs at &, then separate parameter names (left of 

the "=") from parameter values (right of the "=")

URL decode values (e.g., "%7E" becomes "~")

Need special cases for omitted values

(param1=val1&

param2=

¶m3=val3) and repeated 

params (

param1=val1

¶m2=val2&

param1=val3

) 

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Reading Form Data 

(Query Data)

getParameter("name")

Returns value as user entered it. I.e., URL decoded value 

of first occurrence of name in query string. 

Works identically for GET and POST requests

Returns null if no such parameter is in query

getParameterValues("name")

Returns an array of the URL decoded values of all 

occurrences of name in query string

Returns a one element array if param not repeated

Returns null if no such parameter is in query

getParameterNames()

Returns Enumeration of request params

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