Java打印和打印預覽實現代碼

import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.print.PageFormat;
import java.awt.print.Printable;
import java.awt.print.PrinterException;
import java.awt.print.PrinterJob;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;
import javax.swing.text.BadLocationException;
import javax.swing.text.Document;
/**

使用了原始的分頁方式去渲染JTextArea，提供了打印預覽機制。
<p>
事實上，我們還可以通過其他方式打印JTextArea：
<ol>
<li>{@code Component.print(Graphics g);} or
{@code Component.printAll(Graphics g);}</li>
<li>{@code Component.paint(Graphics g);} or
{@code Component.paintAll(Graphics g);} whose rending may be slightly
different to the previous method (for example, <code>JFrame</code>)</li>
<li>{@code JTable.print();} or {@code JTextComponent.print();} provide
especially powerful and convenient printing mechanism</li>
</ol>

@author Gaowen
*/
public class PrintUIComponent extends JPanel implements ActionListener,

 Printable {

private static final long serialVersionUID = 4797002827940419724L;
 private static JFrame frame;
 private JTextArea textAreaToPrint;
 private PrinterJob job;
 private int[] pageBreaks;// array of page break line positions
 private String[] textLines;
 private Header header;
public PrintUIComponent() {

 super(new BorderLayout());
 textAreaToPrint = new JTextArea(50, 20);
 for (int i = 1; i <= 50; i++) {
     textAreaToPrint.append("Line " + i + "\n");
 }
 JScrollPane scrollPane = new JScrollPane(textAreaToPrint);
 scrollPane.setPreferredSize(new Dimension(250, 200));
 add(scrollPane, BorderLayout.CENTER);
 JButton printButton = new JButton("Print This TextArea");
 printButton.setName("printButton");
 printButton.addActionListener(this);
 JButton printPreviewButton = new JButton("Print Preview");
 printPreviewButton.setName("printPreviewButton");
 printPreviewButton.addActionListener(this);
 JPanel buttonGroup = new JPanel(new GridLayout(2, 1));
 buttonGroup.add(printButton);
 buttonGroup.add(printPreviewButton);
 add(buttonGroup, BorderLayout.SOUTH);

 /* Initialize PrinterJob */
 initPrinterJob();

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

 SwingUtilities.invokeLater(new Runnable() {
     @Override
     public void run() {
         createAndShowGUI();
     }
 });

}
private static void createAndShowGUI() {

 frame = new JFrame("Print UI Example");
 frame.setContentPane(new PrintUIComponent());
 frame.pack();
 frame.setLocationRelativeTo(null);
 frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
 frame.setVisible(true);

}
private void initTextLines() {

 Document doc = textAreaToPrint.getDocument();
 try {
     String text = doc.getText(0, doc.getLength());
     textLines = text.split("\n");
 } catch (BadLocationException e) {
     e.printStackTrace();
 }

}
private void initPrinterJob() {

 job = PrinterJob.getPrinterJob();
 job.setJobName("Print TextArea");// 出現在系統打印任務列表
 job.setPrintable(this);

}
@Override
 public int print(Graphics graphics, PageFormat pageFormat, int pageIndex)

     throws PrinterException {
 /*
  * It is safe to use a copy of this graphics as this will not involve
  * changes to it.
  */
 Graphics2D g2 = (Graphics2D) graphics.create();

 /* Calculate "pageBreaks" */
 Font font = new Font("Serif", Font.PLAIN, 12);
 FontMetrics metrics = g2.getFontMetrics(font);
 int lineHeight = metrics.getHeight();
 if (pageBreaks == null) {
     initTextLines();
     int linesPerPage = (int) (pageFormat.getImageableHeight() / lineHeight);
     int numBreaks = (textLines.length - 1) / linesPerPage;
     pageBreaks = new int[numBreaks];
     for (int b = 0; b < numBreaks; b++) {
         pageBreaks[b] = (b + 1) * linesPerPage;
     }
 }

 /* Condition to exit printing */
 if (pageIndex > pageBreaks.length) {
     return NO_SUCH_PAGE;
 }

 /* (0,0) is outside the imageable area, translate to avoid clipping */
 g2.translate(pageFormat.getImageableX(), pageFormat.getImageableY());

 /* Draw each line that is on this page */
 int y = 0;
 int start = (pageIndex == 0) ? 0 : pageBreaks[pageIndex - 1];
 int end = (pageIndex == pageBreaks.length) ? textLines.length
         : pageBreaks[pageIndex];
 for (int line = start; line < end; line++) {
     y += lineHeight;
     g2.drawString(textLines[line], 0, y);
 }

 /* dispose of the graphics copy */
 g2.dispose();

 /* Tell the caller that this page is part of the printed document */
 return PAGE_EXISTS;

}
@Override
 public void actionPerformed(ActionEvent e) {

 Object actionEventSource = e.getSource();
 if (actionEventSource instanceof JButton) {
     JButton button = (JButton) actionEventSource;
     if (button.getName().equals("printButton")) {
         pageBreaks = null;// reset pagination
         boolean ok = job.printDialog();
         if (ok) {
             try {
                 job.print();
             } catch (PrinterException ex) {
                 /* The job did not successfully complete */
                 ex.printStackTrace();
             }
         }
     } else if (button.getName().equals("printPreviewButton")) {
         pageBreaks = null;// reset pagination
         createAndShowPreviewDialog();
     }
 }

}
private void createAndShowPreviewDialog() {

 JDialog previewDialog = new JDialog(frame, "Print Preview Dialog", true);
 JPanel contentPane = new JPanel(new BorderLayout());
 PreviewArea previewArea = new PreviewArea();
 previewArea.addMouseListener(new PreviewAreaMouseAdapter(previewArea));
 JScrollPane scrollPane = new JScrollPane(previewArea);
 contentPane.add(scrollPane, BorderLayout.CENTER);
 header = new Header(previewArea);
 contentPane.add(header, BorderLayout.NORTH);
 previewDialog.setContentPane(contentPane);
 previewDialog.setSize(600, 600);
 previewDialog
         .setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
 previewDialog.setVisible(true);

}
private class Header extends Component {

 private static final long serialVersionUID = -1741188309769027249L;
 private PreviewArea previewArea;
 private boolean paintable;

 private Header(PreviewArea previewArea) {
     this.previewArea = previewArea;
 }

 private void setPaintable(boolean paintable) {
     this.paintable = paintable;
 }

 @Override
 public void paint(Graphics g) {
     if (paintable) {
         g.setColor(Color.GRAY);
         g.drawString(
                 String.valueOf(previewArea.getPageIndex() + 1)
                         + "/"
                         + String.valueOf(pageBreaks.length + 1)
                         + " pages (Click left mouse button to preview next page; right to previous)",
                 10, 15);
     }
 }

 @Override
 public Dimension getPreferredSize() {
     return new Dimension(super.getPreferredSize().width, 20);
 }

}
private class PreviewArea extends Component {

 private static final long serialVersionUID = -6384174997251439843L;
 private PageFormat pageFormat;
 private int pageIndex;
 private int w;
 private int h;
 private final int marginX = 10;
 private final int marginY = 20;

 private PreviewArea() {
     pageFormat = job.pageDialog(job.defaultPage());
     pageIndex = 0;
     w = (int) pageFormat.getWidth();
     h = (int) pageFormat.getHeight();
 }

 private int getPageIndex() {
     return pageIndex;
 }

 private void setPageIndex(int pageIndex) {
     this.pageIndex = pageIndex;
 }

 @Override
 public Dimension getPreferredSize() {
     return new Dimension(w + 2 * marginX, h + 2 * marginY);
 }

 @Override
 public void paint(Graphics g) {
     Graphics2D g2 = (Graphics2D) g.create();
     g2.translate(marginX, marginY);
     g2.drawRect(0, 0, w, h);
     int ix = (int) (pageFormat.getImageableX() - 1);
     int iy = (int) (pageFormat.getImageableY() - 1);
     int iw = (int) (pageFormat.getImageableWidth() + 1);
     int ih = (int) (pageFormat.getImageableHeight() + 1);
     g2.setStroke(new BasicStroke(1f, BasicStroke.CAP_ROUND,
             BasicStroke.JOIN_ROUND, 10f, new float[] { 5, 5 }, 0f));
     g2.drawRect(ix, iy, iw, ih);
     try {
         PrintUIComponent.this.print(g2, pageFormat, pageIndex);
     } catch (PrinterException e) {
         e.printStackTrace();
     }
     g2.dispose();
     header.setPaintable(true);
     header.repaint();
 }

}
private class PreviewAreaMouseAdapter extends MouseAdapter {

 private PreviewArea previewArea;

 private PreviewAreaMouseAdapter(PreviewArea previewArea) {
     this.previewArea = previewArea;
 }

 @Override
 public void mouseClicked(MouseEvent e) {
     int currentIndex = previewArea.getPageIndex();
     if (e.getButton() == MouseEvent.BUTTON1) {
         /* next page */
         if (currentIndex < pageBreaks.length) {
             previewArea.setPageIndex(currentIndex + 1);
             previewArea.repaint();
         }
     } else if (e.getButton() == MouseEvent.BUTTON3) {
         /* previous page */
         if (currentIndex > 0) {
             previewArea.setPageIndex(currentIndex - 1);
             previewArea.repaint();
         }
     }
 }

}
}</pre>