如何使用JTable使用MessageFormat打印多个标题行

我有一个名为table ，它填充了数据，我还有一个MessageFormat头我想用作头来打印JTable这是MessageFormat ：

 MessageFormat header = new MessageFormat("Product: " + task.getProductName() + " Job: " + task.getJobNumber() + " Task: " + task.getTaskID() ); 

我想在标题中打印3行，一行用于Product，Job和Task

我打印这个table的方式是这样的：

 table.print(JTable.PrintMode.FIT_WIDTH, header, null); 

我似乎无法弄清楚如何在3个单独的行中打印标题，我尝试使用\n创建一个新行，但这似乎不起作用。

Answer 1

这将是一个很长的答案（代码明智），因为我找到的唯一解决方案是实现自定义Printable 。 当然我自己没有编写下面的代码，我主要复制了我从jdk源代码中提取的代码并进行了一些调整。

我们到了：

这就是你说调用print方法的方式：

 DefaultTableModel dtm = new DefaultTableModel(new String[] { "Column 1" }, 1); JTable table = new JTable(dtm) { @Override public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) { return new TablePrintable(this, printMode, headerFormat, footerFormat); } }; 

其中TablePrintable是以下类（对不起这里简明扼要）：

 static class TablePrintable implements Printable { private final JTable table; private final JTableHeader header; private final TableColumnModel colModel; private final int totalColWidth; private final JTable.PrintMode printMode; private final MessageFormat headerFormat; private final MessageFormat footerFormat; private int last = -1; private int row = 0; private int col = 0; private final Rectangle clip = new Rectangle(0, 0, 0, 0); private final Rectangle hclip = new Rectangle(0, 0, 0, 0); private final Rectangle tempRect = new Rectangle(0, 0, 0, 0); private static final int H_F_SPACE = 8; private static final float HEADER_FONT_SIZE = 18.0f; private static final float FOOTER_FONT_SIZE = 12.0f; private final Font headerFont; private final Font footerFont; public TablePrintable(JTable table, JTable.PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) { this.table = table; header = table.getTableHeader(); colModel = table.getColumnModel(); totalColWidth = colModel.getTotalColumnWidth(); if (header != null) { // the header clip height can be set once since it's unchanging hclip.height = header.getHeight(); } this.printMode = printMode; this.headerFormat = headerFormat; this.footerFormat = footerFormat; // derive the header and footer font from the table's font headerFont = table.getFont().deriveFont(Font.BOLD, HEADER_FONT_SIZE); footerFont = table.getFont().deriveFont(Font.PLAIN, FOOTER_FONT_SIZE); } @Override public int print(Graphics graphics, PageFormat pageFormat, int pageIndex) throws PrinterException { // for easy access to these values final int imgWidth = (int) pageFormat.getImageableWidth(); final int imgHeight = (int) pageFormat.getImageableHeight(); if (imgWidth <= 0) { throw new PrinterException("Width of printable area is too small."); } // to pass the page number when formatting the header and footer // text Object[] pageNumber = new Object[] { Integer.valueOf(pageIndex + 1) }; // fetch the formatted header text, if any String headerText = null; if (headerFormat != null) { headerText = headerFormat.format(pageNumber); } // fetch the formatted footer text, if any String footerText = null; if (footerFormat != null) { footerText = footerFormat.format(pageNumber); } // to store the bounds of the header and footer text Rectangle2D hRect = null; Rectangle2D fRect = null; // the amount of vertical space needed for the header and footer // text int headerTextSpace = 0; int footerTextSpace = 0; // the amount of vertical space available for printing the table int availableSpace = imgHeight; // if there's header text, find out how much space is needed for it // and subtract that from the available space if (headerText != null) { graphics.setFont(headerFont); int nbLines = headerText.split("\n").length; hRect = graphics.getFontMetrics().getStringBounds(headerText, graphics); hRect = new Rectangle2D.Double(hRect.getX(), Math.abs(hRect.getY()), hRect.getWidth(), hRect.getHeight() * nbLines); headerTextSpace = (int) Math.ceil(hRect.getHeight() * nbLines); availableSpace -= headerTextSpace + H_F_SPACE; } // if there's footer text, find out how much space is needed for it // and subtract that from the available space if (footerText != null) { graphics.setFont(footerFont); fRect = graphics.getFontMetrics().getStringBounds(footerText, graphics); footerTextSpace = (int) Math.ceil(fRect.getHeight()); availableSpace -= footerTextSpace + H_F_SPACE; } if (availableSpace <= 0) { throw new PrinterException("Height of printable area is too small."); } // depending on the print mode, we may need a scale factor to // fit the table's entire width on the page double sf = 1.0D; if (printMode == JTable.PrintMode.FIT_WIDTH && totalColWidth > imgWidth) { // if not, we would have thrown an acception previously assert imgWidth > 0; // it must be, according to the if-condition, since imgWidth > 0 assert totalColWidth > 1; sf = (double) imgWidth / (double) totalColWidth; } // dictated by the previous two assertions assert sf > 0; // This is in a loop for two reasons: // First, it allows us to catch up in case we're called starting // with a non-zero pageIndex. Second, we know that we can be called // for the same page multiple times. The condition of this while // loop acts as a check, ensuring that we don't attempt to do the // calculations again when we are called subsequent times for the // same page. while (last < pageIndex) { // if we are finished all columns in all rows if (row >= table.getRowCount() && col == 0) { return NO_SUCH_PAGE; } // rather than multiplying every row and column by the scale // factor // in findNextClip, just pass a width and height that have // already // been divided by it int scaledWidth = (int) (imgWidth / sf); int scaledHeight = (int) ((availableSpace - hclip.height) / sf); // calculate the area of the table to be printed for this page findNextClip(scaledWidth, scaledHeight); last++; } // create a copy of the graphics so we don't affect the one given to // us Graphics2D g2d = (Graphics2D) graphics.create(); // translate into the co-ordinate system of the pageFormat g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY()); // to save and store the transform AffineTransform oldTrans; // if there's footer text, print it at the bottom of the imageable // area if (footerText != null) { oldTrans = g2d.getTransform(); g2d.translate(0, imgHeight - footerTextSpace); String[] lines = footerText.split("\n"); printText(g2d, lines, fRect, footerFont, imgWidth); g2d.setTransform(oldTrans); } // if there's header text, print it at the top of the imageable area // and then translate downwards if (headerText != null) { String[] lines = headerText.split("\n"); printText(g2d, lines, hRect, headerFont, imgWidth); g2d.translate(0, headerTextSpace + H_F_SPACE); } // constrain the table output to the available space tempRect.x = 0; tempRect.y = 0; tempRect.width = imgWidth; tempRect.height = availableSpace; g2d.clip(tempRect); // if we have a scale factor, scale the graphics object to fit // the entire width if (sf != 1.0D) { g2d.scale(sf, sf); // otherwise, ensure that the current portion of the table is // centered horizontally } else { int diff = (imgWidth - clip.width) / 2; g2d.translate(diff, 0); } // store the old transform and clip for later restoration oldTrans = g2d.getTransform(); Shape oldClip = g2d.getClip(); // if there's a table header, print the current section and // then translate downwards if (header != null) { hclip.x = clip.x; hclip.width = clip.width; g2d.translate(-hclip.x, 0); g2d.clip(hclip); header.print(g2d); // restore the original transform and clip g2d.setTransform(oldTrans); g2d.setClip(oldClip); // translate downwards g2d.translate(0, hclip.height); } // print the current section of the table g2d.translate(-clip.x, -clip.y); g2d.clip(clip); table.print(g2d); // restore the original transform and clip g2d.setTransform(oldTrans); g2d.setClip(oldClip); // draw a box around the table g2d.setColor(Color.BLACK); g2d.drawRect(0, 0, clip.width, hclip.height + clip.height); // dispose the graphics copy g2d.dispose(); return PAGE_EXISTS; } private void printText(Graphics2D g2d, String[] lines, Rectangle2D rect, Font font, int imgWidth) { g2d.setColor(Color.BLACK); g2d.setFont(font); for (int i = 0; i < lines.length; i++) { int tx; // if the text is small enough to fit, center it if (rect.getWidth() < imgWidth) { tx = (int) (imgWidth / 2 - g2d.getFontMetrics().getStringBounds(lines[i], g2d).getWidth() / 2); // otherwise, if the table is LTR, ensure the left side of // the text shows; the right can be clipped } else if (table.getComponentOrientation().isLeftToRight()) { tx = 0; // otherwise, ensure the right side of the text shows } else { tx = -(int) (Math.ceil(rect.getWidth()) - imgWidth); } int ty = (int) Math.ceil(Math.abs(rect.getY() + i * rect.getHeight() / lines.length)); g2d.drawString(lines[i], tx, ty); } } private void findNextClip(int pw, int ph) { final boolean ltr = table.getComponentOrientation().isLeftToRight(); // if we're ready to start a new set of rows if (col == 0) { if (ltr) { // adjust clip to the left of the first column clip.x = 0; } else { // adjust clip to the right of the first column clip.x = totalColWidth; } // adjust clip to the top of the next set of rows clip.y += clip.height; // adjust clip width and height to be zero clip.width = 0; clip.height = 0; // fit as many rows as possible, and at least one int rowCount = table.getRowCount(); int rowHeight = table.getRowHeight(row); do { clip.height += rowHeight; if (++row >= rowCount) { break; } rowHeight = table.getRowHeight(row); } while (clip.height + rowHeight <= ph); } // we can short-circuit for JTable.PrintMode.FIT_WIDTH since // we'll always fit all columns on the page if (printMode == JTable.PrintMode.FIT_WIDTH) { clip.x = 0; clip.width = totalColWidth; return; } if (ltr) { // adjust clip to the left of the next set of columns clip.x += clip.width; } // adjust clip width to be zero clip.width = 0; // fit as many columns as possible, and at least one int colCount = table.getColumnCount(); int colWidth = colModel.getColumn(col).getWidth(); do { clip.width += colWidth; if (!ltr) { clip.x -= colWidth; } if (++col >= colCount) { // reset col to 0 to indicate we're finished all columns col = 0; break; } colWidth = colModel.getColumn(col).getWidth(); } while (clip.width + colWidth <= pw); } } 

这是结果（我希望这是你所期望的）：

Answer 2

你可以试试

 StringBuilder builder = new StringBuilder(); builder.append("Product: "); builder.append(task.getProductName()); builder.append(System.getProperty("line.separator")); builder.append("Job: "); builder.append(task.getJobNumber()); builder.append(System.getProperty("line.separator")); builder.append("Task: "); builder.append(task.getTaskID(); MessageFormat header = new MessageFormat(builder.toString()); 

如果这不起作用，那么您将不得不设置自己的打印机作业，并根据需要精确布局标题。

Answer 3

如果您在不添加页眉/页脚文本的情况下使用getPrintable方法，则可以将返回的Printable包含/装饰在您可以更好地控制标题的位置，以及指定多行标题的位置。 请参阅提到的那种方法的javadoc

将此Printable包装在另一个中以完全有效，以便创建复杂的报告和文档。 您甚至可以请求将不同的页面呈现为不同大小的可打印区域。 实现必须准备好处理这个（可能通过动态进行布局计算）。 但是，如果必须在页面之间传播列，则为每个页面提供不同的高度可能不适用于PrintMode.NORMAL。

我对Printable的经验不足以帮助您进一步了解如何实现这一目标

Answer 4

基本上，@ data的答案是正确的：没有办法绕过自定义可打印的实现。 使用稍微少一点的c＆p来实现它的方法是使用自定义实现

• 接管页眉/页脚打印
• 委托将表格打印到默认的可打印页面

这种方法的诀窍是欺骗委托tablePrintable，使其相信页面比实际小，使用自定义pageFormat

更多细节（和代码）

Answer 5

我已经使用了两个MessageFormat数组作为解决问题的简洁方法。 您将在下面找到最终结果的打印输出：

代码概述如下：

 try { PrinterJob job = PrinterJob.getPrinterJob(); MessageFormat[] header = new MessageFormat[6]; // Assign the arrays with 6 String values for the headers header[0] = new MessageFormat(""); header[1] = new MessageFormat(theExamSelection); header[2] = new MessageFormat(""); header[3] = new MessageFormat("Scrud 60 - Grade Returns - Random Sample"); header[4] = new MessageFormat(""); header[5] = new MessageFormat(theSubjectSelection+" - "+theLevelSelection+" - "+thePaperSelection); MessageFormat[] footer = new MessageFormat[4]; // Assign the 4 Strings to the footer array footer[0] = new MessageFormat("Assistant Examiner Signature:______________ Date:___ /___ /_____ "); footer[1] = new MessageFormat(""); footer[2] = new MessageFormat(""); footer[3] = new MessageFormat("Advising Examiner Signature:______________ Date:___ /___ /_____ "); //here you place the JTable to print // in this case its called randomSample_gradeBreakdown_jTable // along with the header and footer arrays job.setPrintable(new PrintTableMultiLine(randomSample_gradeBreakdown_jTable, JTable.PrintMode.FIT_WIDTH, header, footer )); job.print(); } catch (java.awt.print.PrinterException e) { System.err.format("Cannot print %s%n", e.getMessage()); JOptionPane.showMessageDialog(this, "Check that your printer is working correctly","PRINT ERROR",JOptionPane.ERROR_MESSAGE ); }