套接字从 dataInputStream 中读取了错误的数据

Question

我想在我的应用程序中使用本地 Wi-Fi 网络发送文本和文件，我认为任何通信都是这种格式：

1字节消息模式（文件或文本）+消息长度长+消息（文本或文件）

这是我写的代码：

private void sendFile() throws JSONException {

    if (outputStream == null)
        return;
    InputStream inputFile = null;
    try {
        outputStream.writeInt(G.FILE_MODE);
        outputStream.writeLong(file.length());
        inputFile = new FileInputStream(file);
        final boolean falg = copyFile(inputFile, outputStream);**
        if (falg)
            G.logToast("not sent");
        else
            G.logToast("sent");
    }
    catch (FileNotFoundException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
        G.logToast("not sent");
    }
    catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } finally {

        try {
            outputStream.flush();
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

}

public static boolean copyFile(InputStream inputStream, OutputStream out) {
    byte[] buffer = new byte[4096];

    try {
        while (inputStream.read(buffer) > 0) {
            out.write(buffer);
        }
    }
    catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } finally
    {
        try {
            inputStream.close();
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

    }

    return true;
}

这是我阅读的代码：

private void readInputStream() {
    // TODO Auto-generated method stub
    while (true) {
        FileOutputStream fos = null;
        try {

            int mode = dataInputStream.readInt();
            G.logW("mode : " + mode);
            if (mode != G.FILE_MODE && mode != G.COMMAND_MODE)
                continue;
            int len = (int) dataInputStream.readLong();
            G.logW("len : " + len);
            file.delete();
            fos = new FileOutputStream(file);
            if (mode == G.COMMAND_MODE)
            {
                byte[] buffer = new byte[len];
                dataInputStream.read(buffer, 0, len);
                analizeCommand(new String(buffer));
            } else if (mode == G.FILE_MODE) {
                byte[] buffer = new byte[4096];

                int filesize = len; // Send file size in separate msg
                int read = 0;
                int totalRead = 0;
                int remaining = filesize;
                while ((read = dataInputStream.read(buffer, 0, Math.min(buffer.length, remaining))) > 0) {
                    totalRead += read;
                    remaining -= read;
                    System.out.println("read " + totalRead + " bytes.");
                    fos.write(buffer, 0, read);
                }
                playRecord();

                G.logW("new file received ");
            }
        }
        catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally
        {
            if (fos != null) {
                try {
                    fos.flush();
                }
                catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                try {
                    fos.close();
                }
                catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }

        }

    }
}

但是当我想在另一台设备上分析消息时，我发现它显示了错误的值

这是我登录的目标设备：

01-25 10:32:36.730 E/SMD     (  129): DCD ON
01-25 10:32:36.970 E/Watchdog(  490): !@Sync 653
01-25 10:32:39.720 W/tag     ( 1917): mode : 2
01-25 10:32:39.730 E/SMD     (  129): DCD ON
01-25 10:32:39.730 W/tag     ( 1917): len : 35840
01-25 10:32:39.750 W/PowerManagerService(  490): Timer 0x3->0x3|0x0
01-25 10:32:41.500 W/tag     ( 1917): new file received 
01-25 10:32:41.500 W/tag     ( 1917): mode : 8323227
01-25 10:32:41.500 W/tag     ( 1917): mode : 13828289
01-25 10:32:41.500 W/tag     ( 1917): mode : 14483649
01-25 10:32:41.510 W/tag     ( 1917): mode : 10813557
01-25 10:32:41.510 W/tag     ( 1917): mode : 4653117
01-25 10:32:41.510 W/tag     ( 1917): mode : 3473461
01-25 10:32:41.510 W/tag     ( 1917): mode : 3473433
01-25 10:32:41.520 W/tag     ( 1917): mode : 1638425
01-25 10:32:41.520 W/tag     ( 1917): mode : 1638425
01-25 10:32:41.520 W/tag     ( 1917): mode : 1638425
01-25 10:32:41.520 W/tag     ( 1917): mode : 65516
01-25 10:32:41.520 W/tag     ( 1917): mode : -3735638
01-25 10:32:41.530 W/tag     ( 1917): mode : -9240708
01-25 10:32:41.530 W/tag     ( 1917): mode : -7405692
01-25 10:32:41.530 W/tag     ( 1917): mode : -2424890
01-25 10:32:41.530 W/tag     ( 1917): mode : -1900554
01-25 10:32:41.530 W/tag     ( 1917): mode : -3080258
01-25 10:32:41.530 W/tag     ( 1917): mode : -4259954
01-25 10:32:41.530 W/tag     ( 1917): mode : -8061070
01-25 10:32:41.540 W/tag     ( 1917): mode : -8585330
01-25 10:32:41.540 W/tag     ( 1917): mode : -8061052
01-25 10:32:41.540 W/tag     ( 1917): mode : -8061080
01-25 10:32:41.540 W/tag     ( 1917): mode : -10420384
01-25 10:32:41.540 W/tag     ( 1917): mode : -10420384

为什么会这样？

Answer 1

socket read wrong data from dataInputStream

没有。你发错了。

经典复制循环错误。
```
while (inputStream.read(buffer) > 0) {
    out.write(buffer);
```
应该是
```
int count;
while ((count = inputStream.read(buffer)) > 0) {
    out.write(buffer, 0, count);
```
目前您在流的末尾写入垃圾，并且数据比您向对等点通告的数据多，因此对等点与应用程序协议不同步。

命令读取问题：

dataInputStream.read(buffer, 0, len);

这是您阅读命令的地方。应该是：

dataInputStream.readFully(buffer, 0, len);

file.delete(); 在 fos = new FileOutputStream(file); 之前是多余的。
您将长度作为 long 发送，然后将其向下转换为 int，并将 int 用于剩余计数。为什么？这意味着您不能发送超过 2GB 的数据，这也意味着如果您这样做，您的代码将返回到相同的 bozo 模式。您似乎从中复制了此代码的我的答案使用 long。为什么要改？

Answer 2

  while (inputStream.read(buffer) > 0) {
        out.write(buffer);
    }

应该是：

 int len = 0;
while ((len = inputStream.read(buffer)) >= 0) {
       // if len equals 0, you should read continue.
        if(len  > 0)
       {
           out.write(buffer,0,len);
       }
    }

套接字从 dataInputStream 中读取了错误的数据

socket read wrong data from dataInputStream

sockets

android

datainputstream