java 浏览器在线预览excel例子

以下是一个使用Java浏览器在线预览Excel的示例代码：

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.InputStream;
import java.net.URL;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;

public class ExcelViewer extends JFrame {
    private static final long serialVersionUID = 1L;
    private JTable table;

    public ExcelViewer(String url) {
        super("Excel Viewer");
        setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                dispose();
            }
        });
        Container contentPane = getContentPane();
        contentPane.setLayout(new BorderLayout());
        JPanel panel = new JPanel();
        panel.setLayout(new BorderLayout());
        table = new JTable();
        panel.add(new JScrollPane(table));
        contentPane.add(panel, BorderLayout.CENTER);
        pack();
        setLocationRelativeTo(null);

        try {
            URL excelUrl = new URL(url);
            InputStream is = excelUrl.openStream();
            Workbook wb = new HSSFWorkbook(is);
            Sheet sheet = wb.getSheetAt(0);
            int numColumns = sheet.getRow(0).getLastCellNum();
            String[] columnNames = new String[numColumns];
            for (int i = 0; i < numColumns; i++) {
                columnNames[i] = sheet.getRow(0).getCell(i).getStringCellValue();
            }
            DefaultTableModel model = new DefaultTableModel(columnNames, 0);
            for (int i = 1; i <= sheet.getLastRowNum(); i++) {
                Row row = sheet.getRow(i);
                Object[] rowData = new Object[numColumns];
                for (int j = 0; j < numColumns; j++) {
                    Cell cell = row.getCell(j);
                    if (cell != null) {
                        switch (cell.getCellType()) {
                            case Cell.CELL_TYPE_BLANK:
                                rowData[j] = "";
                                break;
                            case Cell.CELL_TYPE_BOOLEAN:
                                rowData[j] = cell.getBooleanCellValue();
                                break;
                            case Cell.CELL_TYPE_ERROR:
                                rowData[j] = cell.getErrorCellValue();
                                break;
                            case Cell.CELL_TYPE_FORMULA:
                                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                                wb.write(baos);
                                InputStream formulaIs = new ByteArrayInputStream(baos.toByteArray());
                                Workbook formulaWb = new HSSFWorkbook(formulaIs);
                                Sheet formulaSheet = formulaWb.getSheetAt(0);
                                Cell formulaCell = formulaSheet.getRow(row.getRowNum())
                                        .getCell(cell.getColumnIndex());
                                switch (formulaCell.getCachedFormulaResultType()) {
                                    case Cell.CELL_TYPE_BLANK:
                                        rowData[j] = "";
                                        break;
                                    case Cell.CELL_TYPE_BOOLEAN:
                                        rowData[j] = formulaCell.getBooleanCellValue();
                                        break;
                                    case Cell.CELL_TYPE_ERROR:
                                        rowData[j] = formulaCell.getErrorCellValue();
                                        break;
                                    case Cell.CELL_TYPE_NUMERIC:
                                        rowData[j] = formulaCell.getNumericCellValue();
                                        break;
                                    case Cell.CELL_TYPE_STRING:
                                        rowData[j] = formulaCell.getStringCellValue();
                                        break;
                                }
                                break;
                            case Cell.CELL_TYPE_NUMERIC:
                                rowData[j] = cell.getNumericCellValue();
                                break;
                            case Cell.CELL_TYPE_STRING:
                                rowData[j] = cell.getStringCellValue();
                                break;
                        }
                    } else {
                        rowData[j] = "";
                    }
                }
                model.addRow(rowData);
            }
            table.setModel(model);
        } catch (Exception e) {
            JOptionPane.showMessageDialog(this, "Error loading Excel file: " + e.getMessage(), "Error", JOptionPane.ERROR_MESSAGE);
        }
    }

    public static void main(String[] args) {
        new ExcelViewer("http://example.com/example.xls").setVisible(true);
    }
}

这个Java程序可以从指定的URL加载Excel文件，并将其显示在一个JTable中。可以使用此代码作为基础，根据需要进行修改和扩展。