对url字符串进行编码反编码

URL编码、反编码

- (NSString *)URLEncodedString {
    NSString *result = (NSString *)CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault, (CFStringRef)self, NULL, CFSTR("!*'();:@&=+$,/?%#[]"), kCFStringEncodingUTF8);
    return [result autorelease];
}
- (NSString *)URLDecodedString {
    NSString *result = (NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(kCFAllocatorDefault, (CFStringRef)self, CFSTR(""), kCFStringEncodingUTF8);
    return [result autorelease];
}