// 返回UUID
- (void)UUID{
CFUUIDRef uuid_ref = CFUUIDCreate(NULL);
CFStringRef uuid_string_ref= CFUUIDCreateString(NULL, uuid_ref);
CFRelease(uuid_ref);
NSString *tmp = [NSString stringWithString:(__bridge NSString*)uuid_string_ref];
CFRelease(uuid_string_ref);
NSString *uuid = [tmp stringByReplacingOccurrencesOfString:@"-"withString:@""];
[[NSUserDefaultsstandardUserDefaults]setObject:uuid forKey:@"UUID"];
}