Java打印和打印预览实现代码

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;    /**   * 使用了原始的分页方式去渲染JTextArea，提供了打印预览机制。   * <p>   * 事实上，我们还可以通过其他方式打印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");// 出现在系统打印任务列表    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();      }     }    }   }  }