IOS中对Url进行编码和解码

- (NSString *)encodeToPercentEscapeString: (NSString *) input
{
// Encode all the reserved characters, per RFC 3986
// (<http://www.ietf.org/rfc/rfc3986.txt>)
NSString *outputStr = (NSString *)
CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,
(CFStringRef)input,
NULL,
(CFStringRef)@"!*'();:@&=+$,/?%#[]",
kCFStringEncodingUTF8);
return outputStr;
}

- (NSString *)decodeFromPercentEscapeString: (NSString *) input
{
NSMutableString *outputStr = [NSMutableString stringWithString:input];
[outputStr replaceOccurrencesOfString:@"+"
withString:@" "
options:NSLiteralSearch
range:NSMakeRange(0, [outputStr length])];

return [outputStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
}