1. 去掉字串中兩邊的空格

NSCharacterSet *whiteSpace = [NSCharacterSetwhitespaceAndNewlineCharacterSet];

NSString *strr = [[NSStringalloc]initWithString:[self.userTF.textstringByTrimmingCharactersInSet:whiteSpace]];

2. 去掉字串中所有的空格

NSString *strUrl = [[self.dicobjectForKey:@"mailbody_text"]stringByReplacingOccurrencesOfString:

3. 特殊字元處理

 NSString *subString = (__bridge NSString *) CFURLCreateStringByAddingPercentEscapes(kCFAllocatorDefault,            CFStringRef)self.subTextField.text,NULL,CFSTR(":/?#[]@!$&’()*+,;="),                                                 kCFStringEncodingUTF8);