objective-c - 字符串中的 URL 给出 null

Question

我有一个给出路径的字符串，另一个将参数附加到它的字符串。当我将它们放入字符串并显示时，我得到了正确的格式。如果我尝试将整个字符串放入 NSURL 中，它会显示 NULL。获取它的格式是什么？

  NSString *booking=urlForBooking.bookHall;
  NSLog(@" book %@",booking);   // this prints ---    http://10.2.0.76:8080/ConferenceHall/BookingHallServlet

  NSString *bookingString=[booking stringByAppendingString:[NSString stringWithFormat:@"?       employeeId=%@&conferenceHallId=%@&bookingId=%d&purpouse=%@&fromDate=%@&toDate=%@&comments=%@&submit=1",empId,_hallId,_bookingId,_purpose,fromDateStr,toDateStr,_comments]];
  NSLog(@"book str %@",bookingString);  //this prints ---   ?employeeId=3306&conferenceHallId=112&bookingId=0&purpouse=S&fromDate=25/Feb/2013 13:29&toDate=25/Feb/2013 15:29&comments=C&submit=1

  NSURL *bookingURL=[NSURL URLWithString:bookingString];
  NSLog(@"BOOK %@",bookingURL);  //here I'm not getting the url(combined string), it gives null.

Answer 1

这是因为您正在构建的 URL 包含在 URL 中无效的字符，例如空格和斜杠。

您应该转义这些字符:

NSString *bookingPath =[bookingString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *bookingURL=[NSURL URLWithString:bookingPath];

您可能需要替换日期中的斜杠，因为它们可能未正确编码。

NSString *bookingString=[NSString stringWithFormat:@"%@?employeeId=%@&conferenceHallId=%@&bookingId=%d&purpouse=%@&fromDate=%@&toDate=%@&comments=%@&submit=1",
          booking,
          empId,
          _hallId,
          _bookingId,
          [_purpose stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
          [fromDateStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
          [toDateStr stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding],
          [_comments stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];

NSURL *bookingURL=[NSURL URLWithString:bookingString];
NSLog(@"BOOK %@",bookingURL);