Question

我正在尝试将BufferedImage发送到套接字，但它不起作用，但我发现了一种方法来发送它：

// Capture screen
        Robot clientrobot = new Robot();
        Rectangle robotrectangle = new Rectangle(Toolkit.getDefaultToolkit().getScreenSize());
        BufferedImage image = clientrobot.createScreenCapture(robotrectangle);


        ImageIcon imageIcon = new ImageIcon(image);


        // Send captured screen to the server
        output.writeObject(imageIcon);
        output.flush();

但问题是我正在使用javaFX而imageicon是javax.swing这是一个问题所以我需要将它从ImageIcon转换为JavaFX图像所以我找到了一个解决方案，我认为我将其转换为图像：

ImageIcon imageIcon = (ImageIcon) input.readObject();
                            //java.awt.Image awtimage = imageIcon.getImage();
                            BufferedImage bi = new BufferedImage(
                                    imageIcon.getIconWidth(),
                                    imageIcon.getIconHeight(),
                                    BufferedImage.TYPE_INT_RGB);
                                Graphics g = bi.createGraphics();
                                // paint the Icon to the BufferedImage.
                                imageIcon.paintIcon(null, g, 0,0);
                                g.dispose();
                            Image img = SwingFXUtils.toFXImage(bi, null);
                            RemoteDesktopFormController.desktopimage = img;

Soo我将转换后的图像发送到其他类公共静态图像img;然后当我尝试使用这个设置图像时：imgviewhere.setImage（desktopimage）;它给我带来了3个错误：

“JavaFX Application Thread”java.lang.RuntimeException：java.lang.reflect.InvocationTargetException
java.lang.reflect.InvocationTargetException
显示java.lang.NullPointerException

错误3让我感到惊讶它说它的null意味着代码没有执行任何东西所以我发送一个空的空图像？我不这么认为可能是转换错误？我不这么认为，因为我从stackoverflow问题抓到了22票，soo有没有人有解决我的问题？如果你需要一个完整的错误日志，那就是：

CLICK ME PASTEBIN LINK

如果你需要别的东西告诉我，我会发布它。感谢

完整的RemoteDesktopFormController类代码：

package application;

import java.net.URL;
import java.util.ResourceBundle;

import javafx.event.ActionEvent;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.CheckBox;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.input.KeyEvent;
import javafx.scene.input.MouseEvent;

public class RemoteDesktopFormController implements Initializable {

    @SuppressWarnings("unused")
    private boolean remotecontrolenabled = false;
    public static boolean receivingdesktop = false;
    public static Image desktopimage;
    //private int desktopreceiverate = 50;

    @FXML
    private ImageView RemoteDekstopFormDesktopImageView;

    @FXML
    private CheckBox RemoteDekstopFormRemoteControlCheckBox;

    public void startreceivingscreen(ActionEvent event){

        if (receivingdesktop == false){

            try {

                MainController.output.writeObject("RECEIVEDESKTOP-configstream");
                MainController.output.flush();

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

        } else if(receivingdesktop == true){

            System.out.println("Already receiving desktop!");

        }

    }

    public void stopreceivingscreen(ActionEvent event){

        if (receivingdesktop == true){

            try {

                MainController.output.writeObject("RECEIVEDESKTOP-configstream");
                MainController.output.flush();
                receivingdesktop = false;

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

        } else if (receivingdesktop == false){

            System.out.println("You aren't receiving desktop!");

        }

    }

    public void enableremotecontrol(ActionEvent event){

        if (RemoteDekstopFormRemoteControlCheckBox.isSelected() == true){

            RemoteDekstopFormDesktopImageView.setImage(desktopimage);
            remotecontrolenabled = true;

        } else if(RemoteDekstopFormRemoteControlCheckBox.isSelected() == false){

            remotecontrolenabled = false;

        }

    }

    // Remote Control Events
    public void mouseMoved(MouseEvent event){

    }

    public void mousePressed(MouseEvent event){

    }

    public void mouseReleased(MouseEvent event){

    }

    public void keyPressed(KeyEvent event){

    }

    public void keyReleased(KeyEvent event){

    }

    @Override
    public void initialize(URL location, ResourceBundle resources) {



    }

Answer 1

NullPointerException发生在RemoteDesktopFormController.java，第76行：

RemoteDekstopFormDesktopImageView.setImage(desktopimage);

这意味着当执行通过该行时，引用RemoteDekstopFormDesktopImageView为null。解决方案：在捕获操作事件之前，您必须确保正确初始化。

Java通过套接字发送BufferedImage并转换为图像

1 个答案: