问题
I've got a resource on my server named:
some image.png
There's a space in the name. When I type the url into the browser (chrome), it's transforming the space into %20:
some%20.png
WHen I use URLEncoder.encode("some image.png") from my application, I'm getting:
some+image.png
which causes a 404. What's the right way to encode?
回答1:
http://www.permadi.com/tutorial/urlEncoding/
Note that because the character is very commonly used, a special code ( the "+" sign) has been reserved as its URL encoding. Thus the string "A B" can be URL encoded as either "A%20B" or "A+B"
However, your code is probably failing because some parsers/web servers do not handle them equally for base URL portions - and only recognize + = space in the querystring portion
回答2:
IIRC, both + and %20 are valid strings in a URL.
In the path part of the URL + is not reserved[1], and so has no special meaning and does not need to be %-encoded. Therefore, + means literally the + character in the path part of the URL.
In the query part of the URL + is reserved[2], although the purpose is not stated.
However, when using HTML forms the MIME encoding application/x-www-form-urlencoded is used to encode the parameters which (in a HTTP GET request) are included in the query part of the URL[3].
The encoding used by default is based on a very early version of the general URI percent-encoding rules, with a number of modifications such as newline normalization and replacing spaces with "+" instead of "%20". [3]
Sources:
http://www.ietf.org/rfc/rfc2396.txt
[1] Section 3.3
[2] Section 3.4
http://en.wikipedia.org/wiki/Percent-encoding
[3] "The application/x-www-form-urlencoded type"
回答3:
May not be the best solution but you could using path.replace(" ","%20").
As previously stated both "+" and "%20" should work but if "+" does not I think you have to do a manual replace.
来源：https://stackoverflow.com/questions/5130056/urlencoder-encode-and-a-whitespace