JPanel保存为图片

Question

是这样的：JMenuBar中有一个JMenu，JMenu中增加了一个JMenuItem，单击JMenuItem弹出JFileChooser，然后选择路径，最后把一个JPanel保存成图片，这能实现吗？
知道的麻烦告诉一下，不胜感激，最好能给点代码看看！

Answer 1

@Override
public boolean exportOtherShapesImage(File f, DrawPanel panel) {
Dimension imageSize = panel.getSize();
BufferedImage image = new BufferedImage(imageSize.width,
imageSize.height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = image.createGraphics();
panel.paint(g);
g.dispose();
try {
ImageIO.write(image, "png", f);
} catch (IOException e) {
e.printStackTrace();
return false;
}
System.out.println("export Image -->" + f.getAbsoluteFile());
return true;
}

Answer 2

import java.awt.BorderLayout;
import java.awt.EventQueue;
import javax.swing.ImageIcon;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
import javax.swing.filechooser.FileNameExtensionFilter;
import javax.swing.JToolBar;
import javax.swing.JButton;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.FlowLayout;public class Application extends JFrame { /**
 * 
 */
private static final long serialVersionUID = 1L;
private JPanel contentPane;
private JPanel picturePanel;
private JLabel pictureLabel; /**
 * Launch the application.
 */
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Application frame = new Application();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
} /**
 * Create the frame.
 */
public Application() {
setTitle("\u56FE\u7247\u6D4F\u89C8\u5668");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 458, 304);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(new BorderLayout(0, 0));
{
JToolBar toolBar = new JToolBar();
contentPane.add(toolBar, BorderLayout.NORTH);
{
JButton openButton = new JButton("\u6253\u5F00");
openButton.addMouseListener(new MouseAdapter() {
@Override
public void mousePressed(MouseEvent arg0) {
JFileChooser chooser = new JFileChooser();
    FileNameExtensionFilter filter = new FileNameExtensionFilter(
        "JPG & GIF Images", "jpg", "gif");
    chooser.setFileFilter(filter);//设置过滤器
    int returnVal = chooser.showOpenDialog(null);
    if(returnVal == JFileChooser.APPROVE_OPTION) {
       System.out.println(chooser.getSelectedFile()
        .getAbsolutePath());
       pictureLabel.setIcon(new ImageIcon(
        chooser.getSelectedFile().getAbsolutePath()));
    }     
}
});
toolBar.add(openButton);
}
}
{
picturePanel = new JPanel();
contentPane.add(picturePanel, BorderLayout.CENTER);
picturePanel.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));
{
pictureLabel = new JLabel("");
picturePanel.add(pictureLabel);
}
}
}
}

Answer 3

2楼的正确又有问题，如果你那样用panel.paint(g);来设置panel的画笔，到最后你所保存的图片就是所画上去的内容，并不能够将Jpanel上添加的组建画上去，public class PanelImage extends JPanel
{
protected void paintComponent(Graphics g)
{
super.paintComponent(g);
g.drawLine(10, 10, 50, 50);
} public boolean exportOtherShapesImage(File f, JPanel panel)
{
Dimension imageSize = panel.getSize();
BufferedImage image = new BufferedImage(imageSize.width,
imageSize.height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = image.createGraphics();
panel.paint(g);
g.dispose();
try
{
ImageIO.write(image, "png", f);
}
catch (IOException e)
{
e.printStackTrace();
return false;
}
System.out.println("export Image -->" + f.getAbsoluteFile());
return true;
} public static void main(String[] args)
{
PanelImage p = new PanelImage();
p.add(new JLabel("this is my Label"));
p.setSize(500, 500);
p.setVisible(true);
p.exportOtherShapesImage(new File("d:/1.png"), p); JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setBounds(100, 100, 500, 500);
f.add(p);
f.setVisible(true);
}
}运行下就知道保存的只是用g.drawLine方法的图片将添加组建画上去貌似还没有什么方案能行,既然要保存成图片，应该这个JPanel内容都应该用画笔将其画上去

Answer 4

我就是用2楼的办法，也能将JPanel上的组件保存到图片中

Answer 5

 public boolean exportOtherShapesImage(File f, DrawPanel panel) {
        Dimension imageSize = panel.getSize();
        BufferedImage image = new BufferedImage(imageSize.width,
                imageSize.height, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g = image.createGraphics();
        panel.paint(g);
        g.dispose();
        try {
            ImageIO.write(image, "png", f);
        } catch (IOException e) {
            e.printStackTrace();
            return false;
        }
        System.out.println("export Image -->" + f.getAbsoluteFile());
        return true;
    }

Answer 6

private JMenuItem getJMenuItemSaveAs() {
if (jMenuItemSaveAs == null) {
jMenuItemSaveAs = new JMenuItem("另存为");
jMenuItemSaveAs.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
JFileChooser fileChooser=new JFileChooser();
fileChooser.setSelectedFile(new File("default.png"));
int returnVal = fileChooser.showSaveDialog(jMenuItemSaveAs);
if(returnVal==JFileChooser.APPROVE_OPTION){
Dimension imageSize = jPanelTopologyDiscovery.getSize();
BufferedImage image = new BufferedImage(imageSize.width,
                imageSize.height, BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = image.createGraphics();
jPanelTopologyDiscovery.paint(g);
g.dispose();
File topologyImage=fileChooser.getSelectedFile();
 try {
  if(!topologyImage.exists()){
  ImageIO.write(image, "png", topologyImage);
  JOptionPane notice=new JOptionPane ();
notice.showMessageDialog(null, "恭喜，图片保存成功！","保存成功",JOptionPane.INFORMATION_MESSAGE);
  }else{
  int returnValue=0;
  JOptionPane notice=new JOptionPane ();
  returnValue=notice.showConfirmDialog(fileChooser,  "文件"+topologyImage.getName()+"已经存在，是否覆盖？", "保存文件",JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
  if(returnValue==JOptionPane.YES_OPTION){
  ImageIO.write(image, "png", topologyImage);
  //JOptionPane notice=new JOptionPane ();
notice.showMessageDialog(null, "恭喜，图片保存成功！","保存成功",JOptionPane.INFORMATION_MESSAGE);
  }else{
  actionPerformed(e);
  }
  }
            
        } catch (IOException e1) {
            e1.printStackTrace();
        } }
}
});
}
return jMenuItemSaveAs;
}