The message received by the UDP receiver is equal to the buffer length

Project scenario:

UDP communication

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Problem Description

提示：UDP 接收方收到的数据等于缓冲区长度，且远大于发送方发送的数据。

错误代码如下：

public void receivePackage() {
        while(true) {
            byte[] buf = new byte[1024];
            DatagramPacket packet = new DatagramPacket(buf, 0, buf.length);
            try {
                socket.receive(packet);
                byte[] data = packet.getData();
                String s = new String(data, 0, data.length);
                Log.d(TAG, "receivePackage: " + s);
                if(s.equals("BYE")) break;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }

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Cause Analysis:

In fact, when creating a string, the length of the data packet is set incorrectly, and the length should not use data.length

byte[] data = packet.getData();
String s = new String(data, 0, data.length);

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solution:

Use packet.getLength() instead to solve

public void receivePackage() {
        while(true) {
            byte[] buf = new byte[1024];
            DatagramPacket packet = new DatagramPacket(buf, 0, buf.length);
            try {
                socket.receive(packet);
                byte[] data = packet.getData();
                String s = new String(data, 0, packet.getLength());
                Log.d(TAG, "receivePackage: " + s);
                if(s.equals("BYE")) break;
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        socket.close();
    }