Question

java如何实现打印功能?

java如何实现打印功能?打印一个图形化的组件时，有点自动化的感觉,默认情况下，print()方法会调用paint(),大部分情况下这样应用就足够了,但假如还想做一些特别的事情呢?就得知道页面的几何尺寸

Answer 1

Print.java－－打印内容定义

[code]
import java.awt.*;
import java.awt.event.*;
import java.awt.print.*;
import java.awt.image.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
import javax.swing.event.*;
import java.util.*;
import java.io.*;

public class Print implements Printable{
int m_wPage;
int m_hPage;
int m_orientation;
Printable m_target;
int maxNumPage=1;
String title="数据表格打印";
Font titleFont=new Font("黑体",Font.BOLD,14);
boolean hasTail=true;
int tailAlign=0;
int headAlign=0;
int topSpace=0;
int leftSpace=0;

int yStart=0;
int yEnd=0;
int xStart=topSpace;
int xEnd=0;
int x=0,y=0;

String strTemp="打印内容";

public void doPrint(){
try{
m_orientation=PageFormat.PORTRAIT;
//设置打印对象，默认纸张
PrinterJob prnJob=PrinterJob.getPrinterJob();
PageFormat pageFormat=prnJob.defaultPage();
pageFormat.setOrientation(m_orientation);
m_wPage=(int)(pageFormat.getWidth());
m_hPage=(int)(pageFormat.getHeight());

//将待打印的窗体根据默认纸张设置传入打印对象
prnJob.setPrintable(this,pageFormat);
if(!prnJob.printDialog()) return;
prnJob.print();
}catch(PrinterException ex){
ex.printStackTrace();
System.err.println("打印错误："+ex.toString());
}
}
/**
* 初始化打印参数
*/
public void initPrintParameter()
{

}

/**
*构造打印内容，以送打印机打印
*/
public int print(Graphics pg,PageFormat pageFormat,
int pageIndex) throws PrinterException{
//初始化打印参数
initPrintParameter();

//将画布设置为页面大小
pg.translate((int)pageFormat.getImageableX(),
(int)pageFormat.getImageableY());
int wPage=0;
int hPage=0;

//根据打印机页面设置调整画布大小
if(pageFormat.getOrientation()==pageFormat.PORTRAIT){
wPage=(int)pageFormat.getImageableWidth();
hPage=(int)pageFormat.getImageableHeight();
}
else{
wPage=(int)pageFormat.getImageableWidth();
wPage+=wPage/2;
hPage=(int)pageFormat.getImageableHeight();
pg.setClip(0,0,wPage,hPage);
}
wPage=wPage-2*leftSpace;
hPage=hPage-2*topSpace;
xStart=leftSpace;
xEnd=wPage-2;

//为画布设置颜色和字体
int y=topSpace;
pg.setFont(titleFont);
pg.setColor(Color.black);
//画标题，并使其居中
Font fn=pg.getFont();
FontMetrics fm=pg.getFontMetrics();
y+=fm.getAscent();
alignText(title,pg,y,xStart,xEnd,headAlign);
y+=30;

x=leftSpace+2;

Font headerFont=new Font("宋体",Font.BOLD,14);
pg.setFont(headerFont);
fm=pg.getFontMetrics();

int h=fm.getAscent();
yStart=y-1;
y+=h;

pg.setFont(headerFont);
fm=pg.getFontMetrics();
int header=y;
h=fm.getHeight();

//计算行高，每页行数，总行数和指定页码的起始行、结束行
int rowH=Math.max(h,10);
int tailH=rowH+30;
int rowPerPage=0;
int leftPix=0;
if(hasTail){
rowPerPage=(hPage-header-tailH)/rowH;
leftPix=(hPage-header-tailH)%rowH;
yEnd=hPage-leftPix-tailH+2;
}
else{
rowPerPage=(hPage-header)/rowH;
leftPix=(hPage-header)%rowH;
yEnd=hPage-leftPix+2;
}

pg.drawString(strTemp,x,y);

//画表格边框
pg.drawLine(xStart,yStart,xStart,yEnd);
pg.drawLine(xStart,yStart,xEnd,yStart);
pg.drawLine(xEnd,yStart,xEnd,yEnd);
pg.drawLine(xStart,yEnd,xEnd,yEnd);

//打印页码
if(hasTail){
int pageNumber=pageIndex+1;
String s="第"+pageNumber+"页";
alignText(s,pg,yEnd+30,xStart,xEnd,tailAlign);
}
System.gc();
return PAGE_EXISTS;
}

/**
* 文字排列，坐标在y处,显示范围（start-end）
* 0表示居中显示，1表示左对齐，2表示右对齐
*/
private void alignText(String s,Graphics pg,int y,int start,
int end,int mode){
Font fn=pg.getFont();
FontMetrics fm=pg.getFontMetrics();
int wString=fm.stringWidth(s);
int x=start;
switch(mode)
{
case 0:
if((end-start-wString)>0) x=start+(end-start-wString)/2;
break;
case 1:
break;
case 2:
if((end-start-wString)>0) x=start+(end-start-wString);
break;
}
pg.drawString(s,x,y);
}
public static void main(String[] args){
Print p=new Print();
p.doPrint();
}
}
[code]

运行方法：
>javac -d . Print.java
>java Print

自己运行一下