URLEncoder class ?

[mark stone]

what does this method static encode() of the class URLEncoder do ?
what is this translation of a string into x-www-form-urlencoded ??
in one of the examples its usage is like this:
String ss = URLEncoder.encode(args[0]);// the user enters some string at command line
pw.println("string is : "+ss);//where pw is PrintWriter object
here is the api
encode(String s)
Translates a string into x-www-form-urlencoded format.

[Manish Hatwalne]

It is meant for URL encoding the string. When URLs contain a query string, (name=value pairs), the values are encoded using this method. URL encoding includes converting spaces to + or %20 and all other non alpha-numeric characters are converted to their HEX value, which is of the form - %XX, where XX is the HEX value. So my name Manish Hatwalne becomes either Manish+Hatwalne or Manish%20Hatwalne. This can also safely pass values such as /, // and . (period) which have special meaning in the URL.
Of course, there's a corresponding decode method for this. I believe this information is documented in the API as well.
HTH,
- Manish

[Ed Bicker]

Yes, but why do you need to URLEncode a string, in the first place. What good does it serve?

[David O'Meara]

You need to URL encode Strings to put them on a URL, otherwise you could add data that acts strangely or creates illegal URLs.

eg it fixes this:

//broken
String name="Manish Hatwalne";
String url="http://www.google.com/search?q="+name;
 
//fixed
String name="Manish Hatwalne";
String url="http://www.google.com/search?q="+URLEncoder.encode(name);

and it stops this behaving badly:

//broken
String query="100*20%+5?";
String url="http://www.google.com/search?q="+query;
 
//fixed
String query="100*20%+5?";
String url="http://www.google.com/search?q="+URLEncoder.encode(query);

Dave

[Sabarish Sasidharan]

Originally posted by Ed Bicker:
Yes, but why do you need to URLEncode a string, in the first place. What good does it serve?

You would normally not need them because browser does this encoding when it issues a GET request. But in case you are using applets and issuing the GET request programmatically, then you would have to encode() them before it reaches the server.