Java打印和打印预览机制实例代码

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();    }   }  } }}