NSString自带的的方法ＵＲＬ　ｅｎｃｏｄｉｎｇ的编码问题

NSString *password = @"Top+Secret. ";NSString *encoded_normal = [password stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];NSString *encoded_safer = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,  (CFStringRef)password,  NULL,  (CFStringRef)@"!*'();:@&=+$,/?%#[]",  kCFStringEncodingUTF8);// output with %@ otherwise the % escapes cause strange outputNSLog(@"%@", password);NSLog(@"%@", encoded_normal);NSLog(@"%@", encoded_safer);

通过输出情况看，用stringByAddingPercentEscapesUsingEncoding：方法编码时，+号没有编码，存在不ｅｎｃｏｄｅ的情况

推荐使用CFURLCreateStringByAddingPercentEscapes（）

#import@interface NSString (Helpers)// helper functions- (NSString *) stringByUrlEncoding;@end

#import "NSString+Helpers.h"@implementation NSString (Helpers)#pragma mark Helpers- (NSString *) stringByUrlEncoding{return (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL,  (CFStringRef)self,  NULL,  (CFStringRef)@"!*'();:@&=+$,/?%#[]",  kCFStringEncodingUTF8);}