判断邮箱合法性

BOOL NSStringIsValidEmail(NSString *checkString)  {      NString *stricterFilterString = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";     NSString *laxString = @".+@.+\.[A-Za-z]{2}[A-Za-z]*";      NSString *emailRegex = stricterFilter ? stricterFilterString : laxString;      NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];      return [emailTest evaluateWithObject:checkString];  }

?转自:http://www.cocoachina.com/iphonedev/sdk/2011/0621/2960.html