java字符串比较失败？

Question

I'm really puzzled about why this if statement keeps failing. I'm comparing a value and it always returns false.

String userDetail = "john";

 if (sentence.equals(userDetail))
 {

 String returnval = "100%";
 sendData = returnval.getBytes();
 DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
 serverConn.send(sendPacket); 
 }
 else
 {
 String returnval = sentence;
 sendData = returnval.getBytes();
 DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);
 serverConn.send(sendPacket); 
 }

I am positive that "sentence" does equal john. AS you can see I have been doing troubleshooting so in the else statement, I set the return value to sentence and it does return john.

ANy suggestions?

Answer 1

If your variable does appear to equal "john", it is possible that it contains some extra whitespace.

To remove the whitespace in the beginning and end of the string, use:

sentence.trim()