代码如下:

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。

*

* 事实上，我们还可以通过其他方式打印jtextarea：

*

*

{@code component.print(graphics g);} or

* {@code component.printall(graphics g);}

*

{@code component.paint(graphics g);} or

* {@code component.paintall(graphics g);} whose rending may be slightly

* different to the previous method (for example, jframe)

*

{@code jtable.print();} or {@code jtextcomponent.print();} provide

* especially powerful and convenient printing mechanism

*

*

* @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();

}

}

}

}

}

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