我只是使用Java通过socket发送部分图像

Question

我使用了代码从这里如下，只得到了一半的图片发送，谁能告诉我原因吗？获取大小和读取大小的代码对我来说太复杂了，所以我搞不清楚。

public class Send {

public static void main(String[] args) throws Exception {
    Socket socket = new Socket("localhost", 13085);
    OutputStream outputStream = socket.getOutputStream();

    BufferedImage image = ImageIO.read(new File("C:\\Users\\Jakub\\Pictures\\test.jpg"));

    ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
    ImageIO.write(image, "jpg", byteArrayOutputStream);

    byte[] size = ByteBuffer.allocate(4).putInt(byteArrayOutputStream.size()).array();
    outputStream.write(size);
    outputStream.write(byteArrayOutputStream.toByteArray());
    outputStream.flush();
    System.out.println("Flushed: " + System.currentTimeMillis());

    Thread.sleep(120000);
    System.out.println("Closing: " + System.currentTimeMillis());
    socket.close();
}
}


public class Receive {

public static void main(String[] args) throws Exception {
    ServerSocket serverSocket = new ServerSocket(13085);
    Socket socket = serverSocket.accept();
    InputStream inputStream = socket.getInputStream();

    System.out.println("Reading: " + System.currentTimeMillis());

    byte[] sizeAr = new byte[4];
    inputStream.read(sizeAr);
    int size = ByteBuffer.wrap(sizeAr).asIntBuffer().get();

    byte[] imageAr = new byte[size];
    inputStream.read(imageAr);

    BufferedImage image = ImageIO.read(new ByteArrayInputStream(imageAr));

    System.out.println("Received " + image.getHeight() + "x" + image.getWidth() + ": " + System.currentTimeMillis());
    ImageIO.write(image, "jpg", new File("C:\\Users\\Jakub\\Pictures\\test2.jpg"));

    serverSocket.close();
}
} 

正如@EJP评论的那样，最可能的问题是在receive部分，InputStream.Read(Byte[]byteArray)不能完全加载byteArray。如果我使用dataInputStreamdis=new DataInputStream(inputStream)，那么调用dis.readally(byteArray)，它将加载byteArray。虽然我不知道inputStream不能工作的原因。希望有人能说明原因，这将是很好的赞赏。修正后的代码如下：

public class Send {

public static void main(String[] args) throws Exception {
Socket socket = new Socket("localhost", 13085);
OutputStream outputStream = socket.getOutputStream();

BufferedImage image = ImageIO.read(new File("test.jpg"));

ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(image, "jpg", byteArrayOutputStream);

byte[] size = ByteBuffer.allocate(4).putInt(byteArrayOutputStream.size()).array();
outputStream.write(size);
outputStream.write(byteArrayOutputStream.toByteArray());
outputStream.flush();
System.out.println("Flushed: " + System.currentTimeMillis());

Thread.sleep(120000);
System.out.println("Closing: " + System.currentTimeMillis());
socket.close();
}
}

public class Receive {

public static void main(String[] args) throws Exception {
ServerSocket serverSocket = new ServerSocket(13085);
Socket socket = serverSocket.accept();
InputStream inputStream = socket.getInputStream();
DataInputStream dataInputStream=new DataInputStream(inputStream);

System.out.println("Reading: " + System.currentTimeMillis());

byte[] sizeAr = new byte[4];
dataInputStream.read(sizeAr);
int size = ByteBuffer.wrap(sizeAr).getInt();

byte[] imageAr = new byte[size];
dataInputStream.readFully(imageAr);
BufferedImage image = ImageIO.read(new ByteArrayInputStream(imageAr));

System.out.println("Received " + image.getHeight() + "x" + image.getWidth() + ": " + System.currentTimeMillis());
ImageIO.write(image, "jpg", new File("received.jpg"));

serverSocket.close();
}
}

Answer 1

去掉字节数组流，对套接字流执行ImageIO直接操作。

问题是，您假设read()填充了缓冲区，但如果您按照上面的操作，您将完全删除read()。

发送长度也是没有意义的，因为您将关闭他们的套接字之后无论如何。流的结尾足以分隔图像。

也别再睡觉了。网络代码中不需要sleeps。