java - 使用 POI 时移除枚举类的依赖

Question

我想将结果集数据导出到 excelsheet。我正在使用下面的类。

public class ResultSetToExcel {
    private HSSFWorkbook workbook;
    private HSSFSheet sheet;
    private HSSFFont boldFont;
    private HSSFDataFormat format;
    private ResultSet resultSet;
    private FormatType[] formatTypes;

    public ResultSetToExcel(ResultSet resultSet, FormatType[] formatTypes, String sheetName) {
        workbook = new HSSFWorkbook();
        this.resultSet = resultSet;
        sheet = workbook.createSheet(sheetName);
        boldFont = workbook.createFont();
        boldFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        format = workbook.createDataFormat();
        this.formatTypes = formatTypes;
    }

    public ResultSetToExcel(ResultSet resultSet, String sheetName) {
        this(resultSet, null, sheetName);
    }

    private FormatType getFormatType(Class _class) {
        if (_class == Integer.class || _class == Long.class) {
            return FormatType.INTEGER;
        } else if (_class == Float.class || _class == Double.class) {
            return FormatType.FLOAT;
        } else if (_class == Timestamp.class || _class == java.sql.Date.class) {
            return FormatType.DATE;
        } else {
            return FormatType.TEXT;
        }
    }

    public void generate(OutputStream outputStream) throws Exception {
        try {
            ResultSetMetaData resultSetMetaData = resultSet.getMetaData();
            if (formatTypes != null && formatTypes.length != resultSetMetaData.getColumnCount()) {
                throw new IllegalStateException("Number of types is not identical to number of resultset columns. "
                        + "Number of types: " + formatTypes.length + ". Number of columns: "
                        + resultSetMetaData.getColumnCount());
            }
            int currentRow = 0;
            HSSFRow row = sheet.createRow(currentRow);
            int numCols = resultSetMetaData.getColumnCount();
            boolean isAutoDecideFormatTypes;
            if (isAutoDecideFormatTypes = (formatTypes == null)) {
                formatTypes = new FormatType[numCols];
            }
            for (int i = 0; i < numCols; i++) {
                String title = resultSetMetaData.getColumnName(i + 1);
                writeCell(row, i, title, FormatType.TEXT, boldFont);
                if (isAutoDecideFormatTypes) {
                    Class _class = Class.forName(resultSetMetaData.getColumnClassName(i + 1));
                    formatTypes[i] = getFormatType(_class);
                }
            }

            currentRow++; // Write report rows
            while (resultSet.next()) {
                row = sheet.createRow(currentRow++);
                for (int i = 0; i < numCols; i++) {
                    Object value = resultSet.getObject(i + 1);
                    writeCell(row, i, value, formatTypes[i]);
                }
            }
            // Autosize columns
            for (int i = 0; i < numCols; i++) {
                sheet.autoSizeColumn((short) i);
            }
            workbook.write(outputStream);
        } finally {
            outputStream.close();
        }
    }

    public void generate(File file) throws Exception {
        generate(new FileOutputStream(file));
    }

    private void writeCell(HSSFRow row, int col, Object value, FormatType formatType) throws NestableException {
        writeCell(row, col, value, formatType, null, null);
    }

    private void writeCell(HSSFRow row, int col, Object value, FormatType formatType, HSSFFont font)
            throws NestableException {
        writeCell(row, col, value, formatType, null, font);
    }

    private void writeCell(HSSFRow row, int col, Object value, FormatType formatType, Short bgColor, HSSFFont font)
            throws NestableException {
        HSSFCell cell = HSSFCellUtil.createCell(row, col, null);
        if (value == null) {
            return;
        }
        if (font != null) {
            HSSFCellStyle style = workbook.createCellStyle();
            style.setFont(font);
            cell.setCellStyle(style);
        }
        switch (formatType) {
        case TEXT:
            cell.setCellValue(value.toString());
            break;
        case INTEGER:
            cell.setCellValue(((Number) value).intValue());
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.DATA_FORMAT, HSSFDataFormat
                    .getBuiltinFormat(("#,##0")));
            break;
        case FLOAT:
            cell.setCellValue(((Number) value).doubleValue());
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.DATA_FORMAT, HSSFDataFormat
                    .getBuiltinFormat(("#,##0.00")));

            break;
        case DATE:
            cell.setCellValue((Timestamp) value);
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.DATA_FORMAT, HSSFDataFormat
                    .getBuiltinFormat(("m/d/yy")));
            break;
        case MONEY:
            cell.setCellValue(((Number) value).intValue());
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.DATA_FORMAT, format
                    .getFormat("($#,##0.00);($#,##0.00)"));
            break;
        case PERCENTAGE:
            cell.setCellValue(((Number) value).doubleValue());
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.DATA_FORMAT, HSSFDataFormat
                    .getBuiltinFormat("0.00%"));
        }
        if (bgColor != null) {
            HSSFCellUtil.setCellStyleProperty(cell, workbook, HSSFCellUtil.FILL_FOREGROUND_COLOR, bgColor);
            HSSFCellUtil
                    .setCellStyleProperty(cell, workbook, HSSFCellUtil.FILL_PATTERN, HSSFCellStyle.SOLID_FOREGROUND);
        }
    }

    public enum FormatType {
        TEXT, INTEGER, FLOAT, DATE, MONEY, PERCENTAGE
    }
}

和实现上述代码的类

ResultSetToExcel resultSetToExcel = new ResultSetToExcel(rs,        new ResultSetToExcel.FormatType[] { ResultSetToExcel.FormatType.TEXT, ResultSetToExcel.FormatType.TEXT,            ResultSetToExcel.FormatType.INTEGER, ResultSetToExcel.FormatType.MONEY }, "Employee List");    resultSetToExcel.generate(new File("c:\\employees.xls"));

参考： http: //www.codereye.com/2009/09/converting-resultset-to-excel-table-in.html

上面的代码将数据写入 excel 文件，但我需要传递列的数据类型。我的问题是如何从上面的代码中删除 FormatType 类依赖项。FormatType 是枚举并保存所有数据类型。