iOS URLEncode

.h文件：
+ (NSString *)URLEncodedString:(NSString *)unencodedString;


.m文件：
+ (NSString *)URLEncodedString:(NSString *)unencodedString{     
    NSString *charactersToEscape = @"?!@#$^&%*+,:;='\"`<>()[]{}/\\| ";
//#%<>[\]^`{|} //@"!*'();:@&=+$,/?%#[]"
    NSCharacterSet *allowedCharacters = [[NSCharacterSet 
characterSetWithCharactersInString:charactersToEscape] invertedSet];
    NSString *encodedString = [unencodedString 
stringByAddingPercentEncodingWithAllowedCharacters:allowedCharacters];
    return encodedString;
}


//使用方法：
if(![value isKindOfClass:[NSString class]]) {
  value = [dic[key] stringValue];
}
            
//encode之后的字符串
NSString *values = [NSString stringWithFormat:@"%@,[ToolClass 
URLEncodedString:value]];