Question

DatagramPacket receivePacket = new DatagramPacket(receiveData,
                                               receiveData.length);

_socket.receive(receivePacket);

String sentence = new String(receivePacket.getData());

InetAddress IPAddress = receivePacket.getAddress();

int port = receivePacket.getPort();

if(sentence.equals("hello")) (...)

Question: Why sentence.equal("hello") isn’t true when sentence is "hello"? Is it because of String’s Constructor String(byte[])?

Who can I deal with that?

Thanks

Answer 1

Your string probably contains "hello" but is padded with other junk. You could try

if (sentence.trim().equals("hello")) {...}

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To illustrate:

String s = new String(new byte[]{0, 1, 'h', 'e', 'l', 'l', 'o', 2, 3});
System.out.println(s.equals("hello"));
System.out.println(s.trim().equals("hello"));

false  
true

---

Relevant documentation

• trim