java - Java中通过Socket编程传输图像文件

Question

在我的代码中，客户端向服务器发送图像，服务器应该能够接收它并显示图像名称(此处的HelloNewPic.jpg)并将图像保存在桌面中。

服务器:

public class Server1 {

ServerSocket serverSocket = null;
Socket socket = null;
DataInputStream dataInputStream = null;

public Server1() {
    try {
        serverSocket = new ServerSocket(6002);
        System.out.println("Server is Waiting for request...");
        socket = serverSocket.accept();
        System.out.println("Connected with: " + socket.getInetAddress());
        dataInputStream = new DataInputStream(socket.getInputStream());
        System.out.println("Server Read from client: " + dataInputStream.readUTF());
        BufferedImage image = ImageIO.read(socket.getInputStream());
        System.out.println("Server: Image received from client.");

    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static void main(String[] args) {
    new Server1();
}
}

客户:

public class Client1 {

Socket clientSocket = null;
OutputStream outputStream = null;
DataOutputStream dataOutputStream = null;
InputStream inputStream = null;

public Client1() {
    try {
        clientSocket = new Socket("localhost", 6002);
        outputStream = clientSocket.getOutputStream();
        dataOutputStream = new DataOutputStream(outputStream);
        inputStream = clientSocket.getInputStream();

        dataOutputStream.writeUTF("Hello");
        System.out.println("Client to server says: Hello");
        BufferedImage image = ImageIO.read(new File("HelloNewPic.jpg"));
        ImageIO.write(image, "JPG", clientSocket.getOutputStream());
        System.out.println("Client: Image sent to server");

    } catch (Exception e) {
        e.printStackTrace();
    }
}

public static void main(String[] args) {
    new Client1();
}
}

在客户端，也不异常(exception):

Client to server says: Hello
Client: Image sent to server

但服务器端出现异常:

Server is Waiting for request...
Connected with: /127.0.0.1
Server Read from client: Hello
java.net.SocketException: Connection reset
    at java.net.SocketInputStream.read(SocketInputStream.java:189)
    at java.net.SocketInputStream.read(SocketInputStream.java:121)
    at javax.imageio.stream.FileCacheImageInputStream.readUntil(FileCacheImageInputStream.java:141)
    at javax.imageio.stream.FileCacheImageInputStream.read(FileCacheImageInputStream.java:187)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.readImage(Native Method)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.readInternal(JPEGImageReader.java:1158)
    at com.sun.imageio.plugins.jpeg.JPEGImageReader.read(JPEGImageReader.java:966)
    at javax.imageio.ImageIO.read(ImageIO.java:1448)
    at javax.imageio.ImageIO.read(ImageIO.java:1352)
    at networking.Server1.<init>(Server1.java:23)
    at networking.Server1.main(Server1.java:32)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)

Answer 1

1. 您的主要问题是客户端永远不会关闭连接，它只是退出，这会导致某些操作系统执行中止关闭，从而在接收器处产生“连接重置”。

2. 您不需要仅使用 ImageIO 来发送图片。只需读取和写入字节即可。使用 ImageIO 只会浪费大量时间和空间。服务器应该能够使用 ImageIO 作为图像读取字节，无论 ImageIO 发送它们还是直接来自 JPEG 文件。