URL appears special character, need to encode

1) Network access request: Chinese space character encoding/decoding

       stringbyaddingpercentescapesusingencoding (only a total of 14 characters for ' #%^{}[]|\ ' <> plus spaces, excluding "&?") iOS9 will be eliminated, it is recommended to use the Stringbyaddingpercentencodingwithallowedcharacters method

Urlfragmentallowedcharacterset "#%<>[\]^ ' {|}

Urlhostallowedcharacterset "#%/<>[email protected]\^ ' {|}

Urlpasswordallowedcharacterset "#%/:<>[email protected][\]^ ' {|}

Urlpathallowedcharacterset "#%;<>? [\]^`{|}

Urlqueryallowedcharacterset "#%<>[\]^ ' {|}

Urluserallowedcharacterset "#%/:<>[email protected][\]^"

(2) Network access request: Chinese space character decoding

stringbyremovingpercentencoding----Xcode7 may be prompted to replace stringbyaddingpercentescapesusingencoding with this method, depending on whether it is decoded to differentiate

*/
Instead of stringbyaddingpercentescapesusingencoding

Let Customallowedset = Nscharacterset (charactersinstring: "' #%^{}\" []|\\<> "). Invertedset

For example:

NSString *urlstr = [NSString stringwithformat:@ "%@/uploadfeedback?sessionid=%@&content=%@", KMainURL, [ Mysharedclass Sharedinstance].sessionid, _textview.text];

URLSTR = [Urlstr stringbyaddingpercentencodingwithallowedcharacters:[nscharacterset Urlqueryallowedcharacterset]];

URL appears special character, need to encode