在Java環境中,可以使用 java.awt.Toolkit.getScreenResolution()可以得到屏幕每英寸的象素數,但是好像沒有什么方法能知道某一臺打印機的分辨率,更別提去控制打印粒度了。于是可恥的使用著丑陋的缺省打印精度幾年后，終于找到了解決方法，不知道該高興還是悲傷，其原理說出來也是非常的簡單：
提高打印精度，其實就是把本來是A3紙的內容往A4紙里畫，也就是說，打印區域（這里對應著Java里的Graphics對象）需要縮小，然后由于缺省情況下打印是照72DPI來打的，不做改變的話，打印內容也會跟著變小。這樣就不是我們想要的效果了，所以還得把打印內容成比例放大。一個縮小，一個放大，于是畫完后，在指定大小的紙張內，便容納了比以往更多象素的內容，這下世界總算完美了。
以上做法形象的說應該是這樣：把需要產生的圖形對象先放大，畫在一張“紙上”，然后整體縮小，這樣精度就提高了。
tips 1：在一般企業報表表格打印中，使用144DPI得到的表格線的寬度看起來最舒服。
tips 2：現在號稱600DPI的打印機其實是576DPI，如果想使用這個分辨率的精度，需要用好一點的紙張，因為已經到極限了，紙張稍差點，打印墨粉就沾不上，導致線體殘缺。
附源碼（修改分辨率就改動變量iResMul就好）：
import java.awt.*;
import java.awt.print.*;
public class MyPrintableObject implements Printable 
{
public int iResMul = 1; // 1 = 72 dpi; 4 = 288 dpi
public int print(Graphics g, PageFormat pf, int iPage)
throws PrinterException {
final int FONTSIZE = 12;
final double PNT_MM = 25.4 / 72.;
if (0 != iPage)
return NO_SUCH_PAGE;
try {
int iPosX = 1;
int iPosY = 1;
int iAddY = FONTSIZE * 3 / 2 * iResMul;
int iWdth = (int) Math.round(pf.getImageableWidth() * iResMul) - 3;
int iHght = (int) Math.round(pf.getImageableHeight() * iResMul) - 3;
int iCrcl = Math.min(iWdth, iHght) - 4 * iResMul;
Graphics2D g2 = (Graphics2D) g;
PrinterJob prjob = ((PrinterGraphics) g2).getPrinterJob();
g2.translate(pf.getImageableX(), pf.getImageableY());
g2.scale(1.0 / iResMul, 1.0 / iResMul);
g2.setFont(new Font("SansSerif", Font.PLAIN, FONTSIZE * iResMul));
g2.setColor(Color.black);
g2.drawRect(iPosX, iPosY, iWdth, iHght);
g2.drawLine(iPosX, iHght / 2 + iWdth / 50, iPosX + iWdth, iHght / 2
- iWdth / 50);
g2.drawLine(iPosX, iHght / 2 - iWdth / 50, iPosX + iWdth, iHght / 2
+ iWdth / 50);
g2.drawOval(iPosX + 2 * iResMul, iHght - iCrcl - 2 * iResMul,
iCrcl, iCrcl);
iPosX += iAddY;
iPosY += iAddY / 2;
g2.drawString("PrinterJob-UserName: " + prjob.getUserName(), iPosX,
iPosY += iAddY);
g2.drawString("Betriebssystem: " + System.getProperty("os.name")
+ " " + System.getProperty("os.version"), iPosX,
iPosY += iAddY);
g2
.drawString("Java-Version: JDK "
+ System.getProperty("java.version"), iPosX,
iPosY += iAddY);
g2.drawString("Width/Height: " + dbldgt(pf.getWidth()) + " / "
+ dbldgt(pf.getHeight()) + " points = "
+ dbldgt(pf.getWidth() * PNT_MM) + " / "
+ dbldgt(pf.getHeight() * PNT_MM) + " mm", iPosX,
iPosY += iAddY);
g2.drawString("Imageable Width/Height: "
+ dbldgt(pf.getImageableWidth()) + " / "
+ dbldgt(pf.getImageableHeight()) + " points = "
+ dbldgt(pf.getImageableWidth() * PNT_MM) + " / "
+ dbldgt(pf.getImageableHeight() * PNT_MM) + " mm", iPosX,
iPosY += iAddY);
g2.drawString("Imageable X/Y: " + dbldgt(pf.getImageableX())
+ " / " + dbldgt(pf.getImageableY()) + " points = "
+ dbldgt(pf.getImageableX() * PNT_MM) + " / "
+ dbldgt(pf.getImageableY() * PNT_MM) + " mm", iPosX,
iPosY += iAddY);
g2.drawString("versuchte Druckaufl sung: " + 72 * iResMul + " dpi",
iPosX, iPosY += iAddY);
} catch (Exception ex) {
throw new PrinterException(ex.getMessage());
}
return PAGE_EXISTS;
}
private static double dbldgt(double d) {
return Math.round(d * 10.) / 10.; // show one digit after point
}
public static void main(String[] args) {
PrinterJob pj = PrinterJob.getPrinterJob();
pj.setPrintable(new MyPrintableObject());
if (pj.printDialog()) {
try {
pj.print();
} catch (PrinterException e) {
System.out.println(e);
}
}
}
}
（全文完）