[iOS]百分比编码

#import "URLCode.h"@implementation URLCode/** * urlencode()函数原理:对字符串中除了 -_.之外的所有非字母数字字符都将被替换成百分号（%）后跟两位十六进制数，空格则编码为加号（+） urldecode()函数与urlencode()函数原理相反，用于解码已编码的URL字符串，其原理就是把十六进制字符串转换为中文字符 */+ (NSString *) encode:(NSString *) str{    NSString *result = @"";#if defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && __IPHONE_OS_VERSION_MAX_ALLOWED >= 70000    NSCharacterSet *characterSet = [NSCharacterSet URLUserAllowedCharacterSet];    result = [str stringByAddingPercentEncodingWithAllowedCharacters:characterSet];#else    result = (NSString *)CFBridgingRelease(CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,                                                                                   (CFStringRef)str,                                                                                   NULL,                                                                                   CFSTR("!*'();:@&=+$,/?%#[]"),                                                                                   kCFStringEncodingUTF8));#endif    return result;}+ (NSString*) decode:(NSString *) str{    NSString *result = @"";#if defined(__IPHONE_OS_VERSION_MAX_ALLOWED) && __IPHONE_OS_VERSION_MAX_ALLOWED >= 70000    result = [str stringByRemovingPercentEncoding];#else    result = (NSString *)CFBridgingRelease(CFURLCreateStringByReplacingPercentEscapesUsingEncoding(kCFAllocatorDefault,                                                                                                   (CFStringRef)str,                                                                                                   CFSTR(""),                                                                                                   kCFStringEncodingUTF8));#endif    return result;}@end