NumberFormatException error (parseInt)

java string integer numberformatexception
Alex picture Alex · Mar 11, 2011 · Viewed 11.9k times · Source

Hopefully a very simple query, but it's left me scratching my head.

I have a string, which is just a single integer, and I'm trying to then get that integer out as an int. This on the face of it shouldn't be a problem.

// this is how I create the string (it's the playload from a UDP datagram packet, 
// thought I don't think the origins hugely important - it's juts a test run so the
// stringMessage is always 1 (created by a seperate client process)

  ...
  recvSoc.receive(pac);
  String stringMessage = new String(pac.getData());
  port = pac.getPort();
  System.out.println("RECEIVED: " + stringMessage + " on port:  " + port);
  processMessage(stringMessage);
  ...

// Then in processMessage

public void processMessage(String data) {
  int message;
  message = Integer.parseInt(data);
  ...

This always crashes with a NumberFormatException error. I cannot for the life of me figure out what's causing this, any ideas greatly appreciated. I haven't coded much in Java (recently) so might simply be forgetting something critical or what not.

Exception in thread "main" java.lang.NumberFormatException: For input string: "1"
at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
at java.lang.Integer.parseInt(Integer.java:481)
at java.lang.Integer.parseInt(Integer.java:514)
at udp.UDPServer.processMessage(UDPServer.java:85)
at udp.UDPServer.run(UDPServer.java:52)
at udp.UDPServer.main(UDPServer.java:156)

Answer

Bozho picture Bozho · Mar 11, 2011

If the string is really 1, the exception can't happen. So I would say the string is not actually 1.

do a data.toCharArray() and print each character's code (cast to int). It may turn out that there is a hidden character before the digit, for example. (edit: it appears iluxa mentioned this option in a comment while I was writing the answer)

Try data = data.trim() before passing it to parseInt(..)

Related questions

Error java.lang.NumberFormatException: For input string: ""

I'm trying to read this file C101 VEHICLE NUMBER CAPACITY 25 200 CUSTOMER CUST NO. XCOORD. YCOORD. DEMAND READY TIME DUE DATE SERVICE TIME 0 40 50 0 0 1236 0 1 45 68 10 912 967 90 2 45 70 30 825 870 90 3 42 66 10 65 146 90 4 42 68 10 727 782 90 5 42 65 10 15 67 90 6 40 69 20 621 702 90 7 40 66 20 170 225 90 8 38 68 20 255 324 90 But when I read the file, the program throws me this exception: Exception in thread "main" java.lang.…

Read More
Integer.parse(String str) java.lang.NumberFormatException: Errors

I keep getting number format expectations, even though I'm trimming the strings and they don't contain non numerical characters bizarrely it works for some numbers and not others. Below is an example of a string I get number format exception …

Read More
Converting a string to an integer on Android

How do I convert a string into an integer? I have a textbox I have the user enter a number into: EditText et = (EditText) findViewById(R.id.entry1); String hello = et.getText().toString(); And the value is assigned to the …

Read More