可打印不正常

Question

我有一个系统，用户可以在这个系统中注册每个科目的学生，科目和学生成绩，以及主题和日期。您可以通过输入学生代码并从组合框中选择主题来搜索特定主题中的特定学生成绩。如果你搜索它，这些东西都会显示在jTable1中。

然后，我有一个PRINT按钮。当用户单击“打印”按钮时，jTable1中显示的内容将转到jTable2，这两个表之间的区别在于jTable1显示学生的名称和主题的名称，但是jTable2没有按＆＃39;吨。这是一张更好理解的图片：

http://i.stack.imgur.com/37SNh.png

因此，当用户点击按钮打印jTable2时，我正在使用此代码：

        MessageFormat header = new MessageFormat("Ficha Pedagógica - "+jComboBox1.getSelectedItem());

    MessageFormat footer = new MessageFormat("Página {0,number,integer}");

    try{
        jTable2.print(JTable.PrintMode.NORMAL, header, null);
    }
    catch(java.awt.print.PrinterException e){
        System.out.println("error");
    }

事实是，我想要打印2个标题，但是使用内置打印功能无法实现这一点。所以，在Stack Overflow中，我找到了这个主题：

How to print multiple header lines with MessageFormat using a JTable

在我发现这个之后，我尝试使用那里给出的代码。由于我是初学者，即使代码中包含所有注释，我也无法完全理解它。所以，我试图实现它，但现在，当我点击＆＃34;打印＆＃34;按钮，没有任何反应。这是我打印按钮的代码：

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
        try{
        Class.forName(driver);
        con = DriverManager.getConnection(str_conn,usuario,senha);
        stmt = con.createStatement();
        sql = "select topico, nota, datanota from notas where notas.cod_aluno ="+jTextField1.getText()+" and notas.cod_curso ="+jTextField2.getText()+" order by notas.datanota";
        rs = stmt.executeQuery(sql);
        if(rs == null){
            return;
        }
        ResultSetMetaData rsmd;
        rsmd = rs.getMetaData();
        Vector vetColuna = new Vector();
        for(int i = 0;i<rsmd.getColumnCount();i++){
            vetColuna.add(rsmd.getColumnLabel(i+1));
        }
        Vector vetLinhas = new Vector();

        while(rs.next()){
            Vector vetLinha = new Vector();
            for(int i = 0;i<rsmd.getColumnCount();i++){
                vetLinha.add(rs.getObject(i+1));
            }
            vetLinhas.add(vetLinha);
            jTable2.setModel(new DefaultTableModel(vetLinhas,vetColuna));
        }
    }catch(ClassNotFoundException ex){
        JOptionPane.showMessageDialog(null,"Erro\nNão foi possível carregar o driver.");
        System.out.println("Nao foi possivel carregar o driver");
        ex.printStackTrace();
    }catch(SQLException ex){
        JOptionPane.showMessageDialog(null,"Erro\nCertifique-se de que todos os\ncampos estejam preenchidos corretamente.");
        System.out.println("Problema com o SQL");
        ex.printStackTrace();
    }

    /*MessageFormat header = new MessageFormat("Ficha Pedagógica - "+jComboBox1.getSelectedItem());

    MessageFormat footer = new MessageFormat("Página {0,number,integer}");

    try{
        jTable2.print(JTable.PrintMode.NORMAL, header, null);
    }
    catch(java.awt.print.PrinterException e){
        System.out.println("gsgd");
    }*/    
DefaultTableModel dtm = new DefaultTableModel(new String[] { "Column 1" }, 1);
JTable jTable2 = new JTable(dtm) {
@Override
public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
   return new TablePrintable(this, printMode, headerFormat, footerFormat);
        }
    };
}         

＆＃34; TablePrintable＆＃34;的代码class是以下：

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);

    }
}

但是，就像我说的，当我点击＆＃34;打印＆＃34;按钮，没有任何反应。可能出现什么问题？

Answer 1

使用新修改的JTable，您只需要调用它print方法。

DefaultTableModel dtm = new DefaultTableModel(new String[] { "Column 1" }, 1);
JTable jTable2 = new JTable(dtm) {
    @Override
    public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
        return new TablePrintable(this, printMode, headerFormat, footerFormat);
    }
};

try{
    jTable2.print(JTable.PrintMode.NORMAL, header, null);
}
catch(java.awt.print.PrinterException e){
    System.out.println("error");
}

因为您已覆盖getPrintable方法以返回自己的实现，所以这将用于物理打印表...

<强>更新

标题文字需要用\n分隔，例如......

MessageFormat header = new MessageFormat("Testing, 01\n02\n03");

哪个可以产生......

<强>更新

尽管我已经知道，但是无法完全运行代码，您的打印代码看起来应该像......

private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {

    Vector vetColuna = new Vector();
    Vector vetLinhas = new Vector();
    try {
        Class.forName(driver);
        con = DriverManager.getConnection(str_conn, usuario, senha);
        stmt = con.createStatement();
        sql = "select topico, nota, datanota from notas where notas.cod_aluno =" + jTextField1.getText() + " and notas.cod_curso =" + jTextField2.getText() + " order by notas.datanota";
        rs = stmt.executeQuery(sql);
        if (rs == null) {
            return;
        }
        ResultSetMetaData rsmd;
        rsmd = rs.getMetaData();
        for (int i = 0; i < rsmd.getColumnCount(); i++) {
            vetColuna.add(rsmd.getColumnLabel(i + 1));
        }

        while (rs.next()) {
            Vector vetLinha = new Vector();
            for (int i = 0; i < rsmd.getColumnCount(); i++) {
                vetLinha.add(rs.getObject(i + 1));
            }
            vetLinhas.add(vetLinha);
        }
    } catch (ClassNotFoundException ex) {
        JOptionPane.showMessageDialog(null, "Erro\nNão foi possível carregar o driver.");
        System.out.println("Nao foi possivel carregar o driver");
        ex.printStackTrace();
    } catch (SQLException ex) {
        JOptionPane.showMessageDialog(null, "Erro\nCertifique-se de que todos os\ncampos estejam preenchidos corretamente.");
        System.out.println("Problema com o SQL");
        ex.printStackTrace();
    }

    MessageFormat header = new MessageFormat("Ficha Pedagógica - " + jComboBox1.getSelectedItem() + "\nNome do Aluno - " + jTextField1.getText());

    DefaultTableModel dtm = new DefaultTableModel(vetLinhas, vetColuna);
    JTable jTable2 = new JTable(dtm) {
        @Override
        public Printable getPrintable(PrintMode printMode, MessageFormat headerFormat, MessageFormat footerFormat) {
            return new TablePrintable(this, printMode, headerFormat, footerFormat);
        }
    };
    try {
        jTable2.setSize(jTable2.getPreferredSize());
        JTableHeader tableHeader = jTable2.getTableHeader();
        tableHeader.setSize(tableHeader.getPreferredSize());
        jTable2.print(JTable.PrintMode.FIT_WIDTH);
    } catch (PrinterException ex) {
        ex.printStackTrace();
    }

}