转（详细的java excel生成）

• 转载出处：http://www.cnblogs.com/bxljoy/p/3939409.html
• 官方介绍

HSSF is the POI Project‘s pure Java implementation of the Excel ‘97(-2007) file format. XSSF is the POI Project‘s pure Java implementation of the Excel 2007 OOXML (.xlsx) file format.

从官方文档中了解到：POI提供的HSSF包用于操作 Excel ‘97(-2007)的.xls文件，而XSSF包则用于操作Excel2007之后的.xslx文件。

• 需要的jar包

POI官网上下载包并解压获取java操作excel文件必须的jar包：

其中dom4j-1.6.1.jar和xbean.jar（下载地址：http://mirror.bjtu.edu.cn/apache/xmlbeans/binaries/   网站：http://xmlbeans.apache.org ）并不包含在POI提供的jar包中，需要单独下载，否则程序会抛出异常：java.lang.ClassNotFoundException:org.apache.xmlbeans.XmlOptions。

• 具体代码

在Eclipse中创建一个java project，将上面列出来的jar包都加入到工程的classpath中，否则引用不到jar包会报错。

直接上代码（代码基本框架来自Apache POI官方网站，自行调整部分）：

创建excel文件并写入内容：

public static void createWorkbook() throws IOException {
        Workbook wb = new HSSFWorkbook();
        String safeName1 = WorkbookUtil.createSafeSheetName("[O‘sheet1]");
        Sheet sheet1 = wb.createSheet(safeName1);

        CreationHelper createHelper = wb.getCreationHelper();
        // Create a row and put some cells in it. Rows are 0 based.
        Row row = sheet1.createRow((short) 0);

        // Create a cell and put a value in it.
        Cell cell = row.createCell(0);
        cell.setCellValue(1234);

        // Or do it on one line.
        row.createCell(2).setCellValue(
                createHelper.createRichTextString("This is a string"));
        row.createCell(3).setCellValue(true);

        // we style the second cell as a date (and time). It is important to
        // create a new cell style from the workbook otherwise you can end up
        // modifying the built in style and effecting not only this cell but
        // other cells.
        CellStyle cellStyle = wb.createCellStyle();
        cellStyle.setDataFormat(createHelper.createDataFormat().getFormat(
                "m/d/yy h:mm"));
        cell = row.createCell(1);
        cell.setCellValue(new Date());
        cell.setCellStyle(cellStyle);

        // you can also set date as java.util.Calendar
        CellStyle cellStyle1 = wb.createCellStyle();
        cellStyle1.setDataFormat(createHelper.createDataFormat().getFormat(
                "yyyyMMdd HH:mm:ss"));
        cellStyle1.setBorderBottom(CellStyle.BORDER_THIN);
        cellStyle1.setBottomBorderColor(IndexedColors.BLACK.getIndex());
        cellStyle1.setBorderLeft(CellStyle.BORDER_THIN);
        cellStyle1.setLeftBorderColor(IndexedColors.GREEN.getIndex());
        cellStyle1.setBorderRight(CellStyle.BORDER_THIN);
        cellStyle1.setRightBorderColor(IndexedColors.BLUE.getIndex());
        cellStyle1.setBorderTop(CellStyle.BORDER_MEDIUM_DASHED);
        cellStyle1.setTopBorderColor(IndexedColors.BLACK.getIndex());
        cell = row.createCell(4);
        cell.setCellValue(Calendar.getInstance());
        cell.setCellStyle(cellStyle1);

        FileOutputStream fileOut = new FileOutputStream("e:/test/workbook.xls");

        wb.write(fileOut);
        fileOut.close();

    }

读取excel文件的内容：

public static void readExcel() throws InvalidFormatException, IOException {
        // Use a file
        Workbook wb1 = WorkbookFactory.create(new File("e:/test/userinfo.xls"));

        Sheet sheet = wb1.getSheetAt(0);
        // Decide which rows to process
        // int rowStart = Math.min(10, sheet.getFirstRowNum());
        // int rowEnd = Math.max(40, sheet.getLastRowNum());
        int rowStart = sheet.getLastRowNum();
        int rowEnd = sheet.getLastRowNum() + 1;

        logger.info(sheet.getFirstRowNum());
        logger.info(sheet.getLastRowNum());

        for (int rowNum = rowStart; rowNum < rowEnd; rowNum++) {
            Row r = sheet.getRow(rowNum);
            int lastColumn = Math.max(r.getLastCellNum(), 10);
            logger.info(lastColumn);
            // To get the contents of a cell, you first need to know what kind
            // of cell it is (asking a string cell for its numeric contents will
            // get you a NumberFormatException for example). So, you will want
            // to switch on the cell‘s type, and then call the appropriate
            // getter for that cell.
            for (int cn = 0; cn < lastColumn; cn++) {
                // Cell cell = r.getCell(cn, Row.RETURN_BLANK_AS_NULL);
                Cell cell = r.getCell(cn);

                switch (cell.getCellType()) {
                case Cell.CELL_TYPE_STRING:
                    logger.info(cell.getRichStringCellValue().getString());
                    break;
                case Cell.CELL_TYPE_NUMERIC:
                    if (DateUtil.isCellDateFormatted(cell)) {
                        logger.info(cell.getDateCellValue());
                    } else {
                        logger.info(cell.getNumericCellValue());
                    }
                    break;
                case Cell.CELL_TYPE_BOOLEAN:
                    logger.info(cell.getBooleanCellValue());
                    break;
                case Cell.CELL_TYPE_FORMULA:
                    logger.info(cell.getCellFormula());
                    break;
                default:
                    logger.info("empty");
                }
            }
        }

    }

下面给出一个具体的例子，实例中的excel文件内容如下：

我们的程序要做的事情是：根据第一行标题的顺序来读取每一行文件的内容，实际标题和内容的顺序是不确定的，但是我们要求按照给定的顺序输出文件内容。

代码如下：

public static void readUserInfo() throws InvalidFormatException,
            IOException {
        String[] titles = { "收费编号", "收费性质", "姓名", "家庭住址", "工作单位", "电话", "手机",
                "小区楼号", "单元号", "楼层", "房间号", "建筑面积（㎡）", "面积依据", "A面积", "A超",
                "A轻体", "B面积", "B超", "B轻体", "用户编号", "所属楼前表表号" };

        //用来存储标题和顺序的map，key为标题，value为顺序号
        Map<String, Integer> titleMap = new HashMap<String, Integer>();
        //将既定顺序写入map
        for (int i=0 ; i<titles.length; i++) {
            titleMap.put(titles[i], i);
        }

        Workbook wb = WorkbookFactory.create(new File("e:/test/userinfo.xls"));
        for (int numSheet = 0; numSheet < wb.getNumberOfSheets(); numSheet++) {
            Sheet xSheet = wb.getSheetAt(numSheet);
            if (xSheet == null) {
                continue;
            }

            // 获取第一行的标题内容
            Row tRow = xSheet.getRow(0);
            //存储标题顺序的数组
            Integer[] titleSort = new Integer[tRow.getLastCellNum()];

            //循环标题
            for (int titleNum = 0; titleNum < tRow.getLastCellNum(); titleNum++) {
                Cell tCell = tRow.getCell(titleNum);
                String title = "";
                if (tCell == null || "".equals(tCell)) {

                } else if (tCell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN) {// 布尔类型处理
                    // logger.info(xCell.getBooleanCellValue());
                } else if (tCell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC) {// 数值类型处理
                    title = doubleToString(tCell.getNumericCellValue());
                } else {// 其他类型处理
                    title = tCell.getStringCellValue();
                }
                //通过获取的标题，从map中读取顺讯号，写入保存标题顺序号的数组
                Integer ts = titleMap.get(title);
                if (ts != null) {
                    titleSort[titleNum] = ts;
                }
            }

            // 循环行Row
            for (int rowNum = 1; rowNum < xSheet.getLastRowNum() + 1; rowNum++) {
                Row xRow = xSheet.getRow(rowNum);
                if (xRow == null) {
                    continue;
                }
                // 循环列Cell
                String[] v = new String[titleSort.length];

                for (int cellNum = 0; cellNum < titleSort.length; cellNum++) {
                    Cell xCell = xRow.getCell(cellNum);
                    String value = "";
                    if (xCell == null || "".equals(xCell)) {

                    } else if (xCell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN) {// 布尔类型处理
                     logger.info(xCell.getBooleanCellValue());
                    } else if (xCell.getCellType() == XSSFCell.CELL_TYPE_NUMERIC) {// 数值类型处理
                        value = doubleToString(xCell.getNumericCellValue());
                    } else {// 其他类型处理
                        value = xCell.getStringCellValue();
                    }

                    //按照标题顺序的编号来存储每一行记录
                    v[titleSort[cellNum]] = value;
//                    logger.info("v[" + titleSort[cellNum] + "] = " + v[titleSort[cellNum]]);
                }

                //循环结果数组，获取的与既定顺序相同
                for (int i = 0; i < v.length; i++) {
                    logger.info(v[i]);
                }
            }
        }
    }

上段程序中用到的工具类doubleToString（将excel中的double类型转为String类型，处理了科学计数法形式的数）：

private static String doubleToString(double d) {
        String str = Double.valueOf(d).toString();
        // System.out.println(str);
        String result = "";
        if (str.indexOf("E") > 2) {
            int index = str.indexOf("E");
            int power = Integer.parseInt(str.substring(index + 1));
            BigDecimal value = new BigDecimal(str.substring(0, index));
            value = value.movePointRight(power);
            result = value.toString();
        } else {
            if (str.indexOf(".0") > 0)
                result = str.substring(0, str.indexOf(".0"));
            else
                result = str;
        }
        return result;
    }

目前对于POI的应用只限于此，并没有再深入，以后写了新的相关内容会继续补充，请大大们批评指正！