第一种：
ClassPathResource classPathResource = new ClassPathResource("excleTemplate/test.xlsx"); InputStream inputStream =classPathResource.getInputStream();第二种：
InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("excleTemplate/test.xlsx");第三种：
InputStream inputStream = this.getClass().getResourceAsStream("/excleTemplate/test.xlsx");第四种：
File file = ResourceUtils.getFile("classpath:excleTemplate/test.xlsx"); InputStream inputStream = new FileInputStream(file);第一种
System.getProperty("user.dir");第二种
File directory = new File("src/main/resources"); String courseFile = directory.getCanonicalPath();这种方式也能获取到一样的结果第三种
request.getServletContext().getRealPath("/")//获得的路径不是项目路径，而是c盘下一个tomcat目录路径）Creating Date Cells
Workbook wb = new HSSFWorkbook(); //Workbook wb = new XSSFWorkbook(); CreationHelper createHelper = wb.getCreationHelper(); Sheet sheet = wb.createSheet("new sheet"); // Create a row and put some cells in it. Rows are 0 based. Row row = sheet.createRow(0); // Create a cell and put a date value in it. The first cell is not styled // as a date. Cell cell = row.createCell(0); cell.setCellValue(new Date()); // 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 cell = row.createCell(2); cell.setCellValue(Calendar.getInstance()); cell.setCellStyle(cellStyle); // Write the output to a file try (OutputStream fileOut = new FileOutputStream("workbook.xls")) { wb.write(fileOut); }alignment options
水平对齐（HorizontalAlignment ）和垂直对齐（VerticalAlignment） ==》枚举
Cell cell = row.createCell(column); CellStyle cellStyle = wb.createCellStyle(); // GENERAL,LEFT,CENTER,RIGHT,FILL,JUSTIFY,CENTER_SELECTION,DISTRIBUTED; cellStyle.setAlignment(HorizontalAlignment.CENTER); // TOP,CENTER,BOTTOM,JUSTIFY,DISTRIBUTED; cellStyle.setVerticalAlignment(VerticalAlignment.BOTTOM); cell.setCellStyle(cellStyle);Working with borders
设置边框及边框颜色
Cell cell = row.createCell(column); CellStyle style = wb.createCellStyle(); style.setBorderBottom(BorderStyle.THIN); style.setBottomBorderColor(IndexedColors.BLACK.getIndex()); style.setBorderLeft(BorderStyle.THIN); style.setLeftBorderColor(IndexedColors.GREEN.getIndex()); style.setBorderRight(BorderStyle.THIN); style.setRightBorderColor(IndexedColors.BLUE.getIndex()); style.setBorderTop(BorderStyle.MEDIUM_DASHED); style.setTopBorderColor(IndexedColors.BLACK.getIndex()); cell.setCellStyle(cellStyle);Iterate over rows and cells
情况一：迭代器，可以对workbook中的任意一个cell进行样式等的操作
for (Sheet sheet : wb) { for (Row row : sheet) { for (Cell cell : row) { CellStyle cellStyle = wb.createCellStyle(); cellStyle.setAlignment(HorizontalAlignment.CENTER); cellStyle.setVerticalAlignment(VerticalAlignment.BOTTOM); cellStyle.setBorderBottom(BorderStyle.THIN); cellStyle.setBorderTop(BorderStyle.THIN); cellStyle.setTopBorderColor(IndexedColors.BLACK.getIndex()); cellStyle.setBorderRight(BorderStyle.THIN); cellStyle.setBorderLeft(BorderStyle.THIN); cell.setCellStyle(cellStyle); } } }情况二：getCell(int，MissingCellPolicy)
//MissingCellPolicy{RETURN_NULL_AND_BLANK,RETURN_BLANK_AS_NULL,CREATE_NULL_AS_BLANK;} Cell cell = row.getCell(0, Row.RETURN_BLANK_AS_NULL);Getting the cell contents
// import org.apache.poi.ss.usermodel.*; DataFormatter formatter = new DataFormatter(); Sheet sheet1 = wb.getSheetAt(0); for (Row row : sheet1) { for (Cell cell : row) { CellReference cellRef = new CellReference(row.getRowNum(), cell.getColumnIndex()); System.out.print(cellRef.formatAsString()); System.out.print(" - "); // get the text that appears in the cell by getting the cell value and applying any data formats (Date, 0.00, 1.23e9, $1.23, etc) String text = formatter.formatCellValue(cell); System.out.println(text); // Alternatively, get the value and format it yourself switch (cell.getCellType()) { case CellType.STRING: System.out.println(cell.getRichStringCellValue().getString()); break; case CellType.NUMERIC: if (DateUtil.isCellDateFormatted(cell)) { System.out.println(cell.getDateCellValue()); } else { System.out.println(cell.getNumericCellValue()); } break; case CellType.BOOLEAN: System.out.println(cell.getBooleanCellValue()); break; case CellType.FORMULA: System.out.println(cell.getCellFormula()); break; case CellType.BLANK: System.out.println(); break; default: System.out.println(); } } }