Java: Difference with dis.read() and dis.readUTF() in DataInputStream

reinhard.lee picture reinhard.lee · Jun 5, 2012 · Viewed 11.2k times · Source

Simple Question.

What is Difference with dis.read() and dis.readUTF()?

For example, dis.read() only read to byte array, and dis.readUTF() access String type.

Is it correct?

If Server has implements dis.readUTF(), it can not read byte stream?

@Override
public void run() {
    // TODO Auto-generated method stub
    while(mEnabled)
    {
        if (!mFileReceive) {
            try {
                // read
                String tmpStr = dis.readUTF();
                // here come `dis.readUTF()` <- it is can not read byte array?

                mStringBuffer += tmpStr;

                if (tmpStr.length() >= 4096)
                    continue;
                System.out.println("Print : " + mStringBuffer);

                parse = new ParseJSON(null, mStringBuffer.toString());
                // Ack Message
                if (mAckEnabled) {
                    mFileName = "{opcode:0x06,ACK:C" + parse.getParsedData().get("ACK").substring(1) + "}";
                    dos.writeUTF(mFileName);
                    dos.flush();
                    System.out.println("Ack Message Send : " + mFileName);
                    mFileName = null;
                }
                if (parse.getParsedData().get("opcode").equals("155")) {
                    mFileReceive = true;
                }
                parse.clear();
                parse = null;

            } catch (IOException e) {
                // TODO Auto-generated catch block
                System.out.println("ServerThread disconnect");
                break;
            }

Answer

Muhammad Imran Saeed picture Muhammad Imran Saeed · Jun 5, 2012

readUTF() reads from the stream in a representation of a Unicode character string encoded in modified UTF-8 format; this string of characters is then returned as a String.

You should use read method which takes bytes array as an argument. Here is its explanation:

public final int read(byte[] b) throws IOException

Reads some number of bytes from the contained input stream and stores them into the buffer array b. The number of bytes actually read is returned as an integer.