After sending byte arrays via dataoutputstream, th

Question

For some reasons, I need to send multiple byte arrays separately via server socket, and client socket will receive these byte arrays. After sending byte arrays, I found byte arrays received in client socket are not equal to those in server socket. If I use ObjectOutputStream and ObjectInputStream, then everything works fine, but for my need, I can't use ObjectOutputStream & ObjectInputStream, because my server need to connect more than 2 sockets.

Here is Server and Client code:

Server(Sender):

    private void sendData() throws IOException {
        DataOutputStream outputStream = new DataOutputStream(new BufferedOutputStream(socket.getOutputStream()));

        File file = new File(filePath);
        byte[] fileByte = new byte[(int) file.length()];

        // Convert file into byte array
        FileInputStream fileInputStream = new FileInputStream(file);
        fileInputStream.read(fileByte);

        while (!decoder.isDecoded()) {
            byte[] packet = new byte[encoder.getPacketLength()];
            encoder.getPacket(packet, 0);

            if (Math.random() < 0.1)
                continue;

            // Send data HERE!!!
            outputStream.writeInt(encoder.getPacketLength());
            outputStream.write(packet);

            StringBuilder sb = new StringBuilder();
            for (byte value : packet) {
                sb.append(value);
            }
            serverLog("Packet content= " + sb.toString());

            decoder.addPacket(packet, 0);
        }

        outputStream.close();
        outputStream.flush();
        fileInputStream.close();
    }

Client(Receiver):

public void receiveData() throws UnknownHostException, IOException, ClassNotFoundException {
    in = new BufferedReader(new InputStreamReader(socket.getInputStream()));

    DataInputStream dis = new DataInputStream(new BufferedInputStream(socket.getInputStream()));
    int len = dis.readInt();

    while (!decoder.isDecoded()) {
        byte[] packet = new byte[len];

        dis.read(packet, 0, len);

        StringBuilder sb = new StringBuilder();
        for (byte value : packet) {
            sb.append(value);
        }
        messageArea.append("Packet content= " + sb.toString() + "\n");

        decoder.addPacket(packet, 0);
    }
}

---

log from server:

Packet content= 8312654-7646-55-71-522462106-89115-98-107-66-9445-61-78-99-43-52528422-10765-3719-1243-114-115-5869-119-92-113591131276057-905042126-7557940-2850118-9737-6512759-93-393-89-96104-789-7694747-118-61-79-97-872-4369-82-11923-805-62-9527-38-1195-13107673425588-92-49-44-97-7811812416-781244-100
Packet content= -10295-4-73-809789-87-97-9095-55-11-7440100-2871-89-68-59-3739-2073-1286290-21-106-2-25-1263646-107-84-9-42-4491-418419-469395-61-52-32-85-38-107-8385-6559-1286575-56-1029-5991-7551-10390-25-94-5072-2318-62-12360-818-11719-73710076121-584012212645-20-170-45089-87401082110113-7-1034873-877
Packet content= -37-732-59-1071015223-34-2745-4322265-18-108-97126-22-56083-131-61-16069536-10-7092-36-50-96-72-3133-79-11751-3671-91-48-14-54-113-8295-124-18-78125-117-12811911042-34108-94-33-92-113268272-41-23992553-69-72997619-1166735417-76-126-58121-7595-443265-944-44-124104-201040-803310126-125-8449-8
Packet content= -102110606194-6037-2-63-6025-112-17-36-3629-93112-86-116-54-14118-124121315341-11923-119-12246-1-973-31-22-9-111-12614-37-1456-10456-9450-11823811378-779-111101-31-101-843217-124-16107-108107101-7743-108-100-5475113119-6647-7185-96-683-12710756-9896111-1072318-3982-6288-7496-5514-18373957-71108-3232
Packet content= -6689-124263-68321112-19-6730-68-12223-125105-51444110862-11063-114-41-76-5275-7-15105-865826-5049-12386124123-121-10460-863108-65-481142910461-97-11912453-10718-6711787-91-37-97910-22-1963-88-116114-138375-2082027-128126-8529-3632242-772-105106-35-41-44-573126-7512038-62-733838-434433-9-59
Packet content= -9652035246-1482-59-63699991-47-25-2-15127-55-42-97-106-11966-15-4344462-68-2-916794121-31-11164-40-73-8104342-69-38-122986-11584-57-106-35-49-120-15138-19121-32-88-62-5127-95114-26-34-75-377155-6911914-4210849-116-7028-8180-817585-108-76-3337-21-4589108-121794-85109-6810644-102101106-68-5-127
Packet content= -127-124-61-24479910112178-45-47-952540-122-70100-120-17-5114-127-69-12-38-100-111-21-111-44113-10-12490-72884-9549-1115580-7653-16100-7889-22103-747-476698-9-68-83-301112667-1712127-64-45-746-1054497-7071108-109-9-8946-4259-121-106-121-27-6761-3447-1177476-7271-95-75-107-42-331886-119-10578-6098-128-2287-52
Packet content= 5244-100-68-1215109-27-6810-774491-11-29102-6267-621964-975427701107495-33578037-1924-5611657210-46-16-94-53-92-5282-11353-10359-38-1-385212480-12710119-597634-108-67-49109101-69-7933-10189120-76104-46106-64223-44-10-4789-1213910192-125-60-5-20-37-901-5-104103-739314-4414-1123759-31-45-72
Packet content= 119-4161558-7832-8310329-118-91122-85-37-33-30-52-101087-123784011115-57-31-1166-31-55-43-13-49-5812464-16-1382-30-3810445117659-70810584-46113-11-5111-1251-428299112-816596-1091021353-4679-3526-10363100-10-4-318-49-117-10449103105-11190-94-5310633-2-123-5268-119124-12297-106-114-102110-35-12094-128
Packet content= -381-70-109-26112-2552-92-40-39-22966-36-69-118-116-19-4848-9-12869-102-4558-2198362-121-553776-84-118-93125-12374128555-8688-2-729-43126-3-10083-26-64119-6010577-12263-4-74-44-11028-216447727-5082-104100-3410673529-8970-27110-81-90-1221185-22-249510515-123-157817-43-11961-93141-8512-77-7352

log from client:

Packet content= 8312654-7646-55-71-522462106-89115-98-107-66-9445-61-78-99-43-52528422-10765-3719-1243-114-115-5869-119-92-113591131276057-905042126-7557940-2850118-9737-6512759-93-393-89-96104-789-7694747-118-61-79-97-872-4369-82-11923-805-62-9527-38-1195-13107673425588-92-49-44-97-7811812416-781244-100
Packet content= 000110-10295-4-73-809789-87-97-9095-55-11-7440100-2871-89-68-59-3739-2073-1286290-21-106-2-25-1263646-107-84-9-42-4491-418419-469395-61-52-32-85-38-107-8385-6559-1286575-56-1029-5991-7551-10390-25-94-5072-2318-62-12360-818-11719-73710076121-584012212645-20-170-45089-87401082110113-7-103
Packet content= 4873-877000110-37-732-59-1071015223-34-2745-4322265-18-108-97126-22-56083-131-61-16069536-10-7092-36-50-96-72-3133-79-11751-3671-91-48-14-54-113-8295-124-18-78125-117-12811911042-34108-94-33-92-113268272-41-23992553-69-72997619-1166735417-76-126-58121-7595-443265-944-44-124104-201040
Packet content= -803310126-125-8449-8000110-102110606194-6037-2-63-6025-112-17-36-3629-93112-86-116-54-14118-124121315341-11923-119-12246-1-973-31-22-9-111-12614-37-1456-10456-9450-11823811378-779-111101-31-101-843217-124-16107-108107101-7743-108-100-5475113119-6647-7185-96-683-12710756-9896111-1072318-3982-6288
Packet content= -7496-5514-18373957-71108-3232000110-6689-124263-68321112-19-6730-68-12223-125105-51444110862-11063-114-41-76-5275-7-15105-865826-5049-12386124123-121-10460-863108-65-481142910461-97-11912453-10718-6711787-91-37-97910-22-1963-88-116114-138375-2082027-128126-8529-3632242-772-105106-35-41
Packet content= -44-573126-7512038-62-733838-434433-9-59000110-9652035246-1482-59-63699991-47-25-2-15127-55-42-97-106-11966-15-4344462-68-2-916794121-31-11164-40-73-8104342-69-38-122986-11584-57-106-35-49-120-15138-19121-32-88-62-5127-95114-26-34-75-377155-6911914-4210849-116-7028-8180-817585-108-76
Packet content= -3337-21-4589108-121794-85109-6810644-102101106-68-5-127000110-127-124-61-24479910112178-45-47-952540-122-70100-120-17-5114-127-69-12-38-100-111-21-111-44113-10-12490-72884-9549-1115580-7653-16100-7889-22103-747-476698-9-68-83-301112667-1712127-64-45-746-1054497-7071108-109-9-8946-4259-121-106-121-27-67
Packet content= 61-3447-1177476-7271-95-75-107-42-331886-119-10578-6098-128-2287-520001105244-100-68-1215109-27-6810-774491-11-29102-6267-621964-975427701107495-33578037-1924-5611657210-46-16-94-53-92-5282-11353-10359-38-1-385212480-12710119-597634-108-67-49109101-69-7933-10189120-76104-46106-64223-44
Packet content= -10-4789-1213910192-125-60-5-20-37-901-5-104103-739314-4414-1123759-31-45-72000110119-4161558-7832-8310329-118-91122-85-37-33-30-52-101087-123784011115-57-31-1166-31-55-43-13-49-5812464-16-1382-30-3810445117659-70810584-46113-11-5111-1251-428299112-816596-1091021353-4679-3526-10363100
Packet content= -10-4-318-49-117-10449103105-11190-94-5310633-2-123-5268-119124-12297-106-114-102110-35-12094-128000110-381-70-109-26112-2552-92-40-39-22966-36-69-118-116-19-4848-9-12869-102-4558-2198362-121-553776-84-118-93125-12374128555-8688-2-729-43126-3-10083-26-64119-6010577-12263-4-74-44-11028-216447727-5082

Everyone can see there are always 6 integers "000110" inserted into the received packets after the first packet, how do I edit these code to prevent this problem and ensure the sent packets and received packets are equal? Please help me, I would appreciate your kind help. :)

Answer 1

You're assuming that read() filled the buffer, without checking the return value. It isn't specified to do that, only to transfer at least one byte. Use readFully() to get that behaviour.