java - 通过 Socket 发送图像

Question

我在通过套接字(客户端-服务器)发送图像时遇到一个小问题，我只收到“UTF”文本，但没有收到图像对象，代码有问题吗？，

此代码仅发送 UTF txt，并在服务器端接收它，我使用 UTF 文本在服务器端识别图像(名称)，识别后可以将图像对象发送到客户端

    /*
     * ServerSide
     * 
     */
    package Interface_class;

    import configuraciones.procesador;
    import java.awt.image.BufferedImage;
    import java.io.DataInputStream;
    import java.io.DataOutputStream;
    import java.io.File;
    import java.io.IOException;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.net.SocketTimeoutException;
    import javax.imageio.ImageIO;

    /**
     *
     * @author TheCoder
     */
    public class img_monitor extends Thread{
            ServerSocket serverSocket;
           Socket server;
           BufferedImage bimg;
            byte[] bytes;
           public img_monitor() 
           {
               try{
//Opening server socket
              serverSocket = new ServerSocket(6066);
              System.out.println("Conectado al Socket!");
    }
               catch(IOException ex){
                   System.out.println("Error en: "+ex);

              }
           }

           public void run()
           {
//This class gets the path from a property file (works well)
            procesador obj = new procesador();
            obj.UBARCHIVO_CONFIG();

               while(true)
              {
                   try
                   {

                      server = serverSocket.accept();
                      System.out.println("Nuevo cliente conectado!");
                      DataInputStream din=new DataInputStream(server.getInputStream());
                      DataOutputStream dout=new DataOutputStream(server.getOutputStream());                 
    //Receiving image "name" from client as txt
                      String nombre = din.readUTF();
                      System.out.println(nombre);
//Using path+name of image to identify and send over socket
                      bimg = ImageIO.read(new File(obj.getRuta_arch_img()+nombre));
                      System.out.println(obj.getRuta_arch_img()+nombre);
                      ImageIO.write(bimg,"JPG",dout);
                      System.out.println("Image sent!!!");
    //                  server.close();

                      //lblimg.setIcon(img);
                  }
                 catch(IOException e)
                 {
                      e.printStackTrace();
                      break;
                 }
                 catch(Exception ex)
                {
                      System.out.println(ex);
                }
              }
           }

    }

客户端

    /*
     * Client Side 
     * 
     */
    package Interface_class;

    import java.awt.image.BufferedImage;
    import java.io.DataInputStream;
    import java.io.DataOutputStream;
    import java.io.IOException;
    import java.net.ServerSocket;
    import java.net.Socket;
    import java.net.SocketTimeoutException;
    import javax.imageio.ImageIO;

    /**
     *
     * @author TheCoder
     */
    public class Obtener_imagen extends Thread {

        public Obtener_imagen() {
            System.out.println("Loading  Socket!");

        }

        public void run() {
//The class below gets info from database
            CLIENTINFO_CLASS obj = new CLIENTINFO_CLASS();
            obj.consulta();
            try {
                Socket socket = new Socket("localhost", 6066);
    //              DataInputStream din = new DataInputStream(socket.getInputStream());
                DataOutputStream dout = new DataOutputStream(socket.getOutputStream());
               //Using this to send image "name" to server, so it can identify and send image to client
 dout.writeUTF(obj.getImg_name());
                BufferedImage img = ImageIO.read(ImageIO.createImageInputStream(socket.getInputStream()));
                System.out.println("Image received!!!!");
    //                socket.close();
            } catch (IOException ex) {
                System.out.println("Error al abrir el socket" + ex);
            }
        }
    }

Answer 1

发送图像后，您不会关闭套接字，因此客户端永远不会停止读取。服务器应该关闭套接字输出流，并在finally block 中关闭套接字本身。

客户端还应该在finally block 中关闭他的套接字。

编辑:您不需要使用 ImageIO 在服务器上读取和写入图像文件，除非您要更改格式。只需复制字节即可。