引入jar包
首先，在maven中pom.xml添加
<dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>3.17</version> </dependency>
要用XSSFWorkbook和SXSSHWorkbook（处理大量数据用）还需引入
<dependency> <groupId>org.apache.poi</groupId> <artifactId>poi-ooxml</artifactId> <version>3.17</version> </dependency>
代码
新建Excel文件，并制定Excel版本，表单名称，表头，数据及Excel文件路径
/** * 新建Excel文件，New Workbook * @param excelType 可为null，Excel版本，可为2003（.xls）或者2007（.xlsx）,默认为2003版本 * @param sheetName 新建表单名称 * @param headList 表头List集合 * @param dataList 数据List<List<集合>>(行<列>) * @param path 新建excel路径 * @return */ public static boolean createWorkBook(String excelType, String sheetName, List<String> headList,List<List<String>> dataList,String path){ Workbook wb = null; /*创建文件*/ if (excelType == null || excelType.endsWith("2003")) { /*操作Excel2003以前（包括2003）的版本，扩展名是.xls */ wb = new HSSFWorkbook(); }else if (excelType.endsWith("2007")){ /*XSSFWorkbook:是操作Excel2007的版本，扩展名是.xlsx */ wb = new XSSFWorkbook(); }else { //默认为2003版本 /*操作Excel2003以前（包括2003）的版本，扩展名是.xls */ wb = new HSSFWorkbook(); } /*Excel文件创建完毕*/ CreationHelper createHelper = wb.getCreationHelper(); //创建帮助工具 /*创建表单*/ Sheet sheet = wb.createSheet(sheetName!=null?sheetName:"new sheet"); // Note that sheet name is Excel must not exceed 31 characters（注意sheet的名字的长度不能超过31个字符，若是超过的话，会自动截取前31个字符） // and must not contain any of the any of the following characters:（不能包含下列字符） // 0x0000 0x0003 colon (:) backslash (\) asterisk (*) question mark (?) forward slash (/) opening square bracket ([) closing square bracket (]) /*若是包含的话，会报错。但有一个解决此问题的方法， 就是调用WorkbookUtil的createSafeSheetName(String nameProposal)方法来创建sheet name, 若是有如上特殊字符，它会自动用空字符来替换掉，自动过滤。*/ /*String safeName = WorkbookUtil.createSafeSheetName("[O'Brien's sales*?]"); // returns " O'Brien's sales "过滤掉上面出现的不合法字符 Sheet sheet3 = workbook.createSheet(safeName); //然后就创建成功了*/ /*表单创建完毕*/ //设置字体 Font headFont = wb.createFont(); headFont.setFontHeightInPoints((short)14); headFont.setFontName("Courier New"); headFont.setItalic(false); headFont.setStrikeout(false); //设置头部单元格样式 CellStyle headStyle = wb.createCellStyle(); headStyle.setBorderBottom(BorderStyle.THICK); //设置单元格线条 headStyle.setBottomBorderColor(IndexedColors.BLACK.getIndex()); //设置单元格颜色 headStyle.setBorderLeft(BorderStyle.THICK); headStyle.setLeftBorderColor(IndexedColors.BLACK.getIndex()); headStyle.setBorderRight(BorderStyle.THICK); headStyle.setRightBorderColor(IndexedColors.BLACK.getIndex()); headStyle.setBorderTop(BorderStyle.THICK); headStyle.setTopBorderColor(IndexedColors.BLACK.getIndex()); headStyle.setAlignment(HorizontalAlignment.CENTER); //设置水平对齐方式 headStyle.setVerticalAlignment(VerticalAlignment.CENTER); //设置垂直对齐方式 //headStyle.setShrinkToFit(true); //自动伸缩 headStyle.setFont(headFont); //设置字体 /*设置数据单元格格式*/ CellStyle dataStyle = wb.createCellStyle(); dataStyle.setBorderBottom(BorderStyle.THIN); //设置单元格线条 dataStyle.setBottomBorderColor(IndexedColors.BLACK.getIndex()); //设置单元格颜色 dataStyle.setBorderLeft(BorderStyle.THIN); dataStyle.setLeftBorderColor(IndexedColors.BLACK.getIndex()); dataStyle.setBorderRight(BorderStyle.THIN); dataStyle.setRightBorderColor(IndexedColors.BLACK.getIndex()); dataStyle.setBorderTop(BorderStyle.THIN); dataStyle.setTopBorderColor(IndexedColors.BLACK.getIndex()); dataStyle.setAlignment(HorizontalAlignment.LEFT); //设置水平对齐方式 dataStyle.setVerticalAlignment(VerticalAlignment.CENTER); //设置垂直对齐方式 //dataStyle.setShrinkToFit(true); //自动伸缩 /*创建行Rows及单元格Cells*/ Row headRow = sheet.createRow(0); //第一行为头 for (int i=0;i<headList.size();i++){ //遍历表头数据 Cell cell = headRow.createCell(i); //创建单元格 cell.setCellValue(createHelper.createRichTextString(headList.get(i))); //设置值 cell.setCellStyle(headStyle); //设置样式 } int rowIndex = 1; //当前行索引 //创建Rows for (List<String> rowdata : dataList){ //遍历所有数据 Row row = sheet.createRow(rowIndex++); //第一行为头 for (int j = 0;j< rowdata.size();j++){ //编译每一行 Cell cell = row.createCell(j); cell.setCellStyle(dataStyle); cell.setCellValue(createHelper.createRichTextString(rowdata.get(j))); } } /*创建rows和cells完毕*/ /*设置列自动对齐*/ for (int i =0;i<headList.size();i++){ sheet.autoSizeColumn(i); } try (OutputStream fileOut = new FileOutputStream(path)) { //获取文件流 wb.write(fileOut); //将workbook写入文件流 } catch (FileNotFoundException e) { e.printStackTrace(); return false; } catch (IOException e) { e.printStackTrace(); return false; } return true; }
工具类其他方法
public static Workbook getWorkBook(String path) throws IOException, InvalidFormatException { File file = new File(path); //目标Excel文件 File parent = new File(file.getParent()); //Excel的父文件夹 if (!parent.exists()){ //判断父文件夹是否存在 parent.mkdirs(); //建立父文件夹 } Workbook wb = null; if(file.exists()){ //如果文件存在 wb = WorkbookFactory.create(file); //打开文件 }else { //如果目标文件不存在 if (path.endsWith(".xls")) { /*操作Excel2003以前（包括2003）的版本，扩展名是.xls */ wb = new HSSFWorkbook(); } else if (path.endsWith(".xlsx")) { /*XSSFWorkbook:是操作Excel2007的版本，扩展名是.xlsx */ wb = new XSSFWorkbook(); } else { new Exception(path + "后缀名错误!"); } } /*获取表单总数*/ int sheetCount = wb.getNumberOfSheets(); /*获取某一表单总行数*/ Sheet sheet = wb.createSheet(); //Sheet sheet = wb.getSheetAt(0); System.out.println("表单数:"+sheetCount); System.out.println("第一行索引:"+sheet.getFirstRowNum()); System.out.println("最后一行索引"+sheet.getLastRowNum()); int rowIndex = sheet.getLastRowNum()+1; for (int i=0;i<=3;i++) { Row row = sheet.createRow(rowIndex++); for (int j = 0; j < 10; j++) { Cell cell = row.createCell(j); cell.setCellValue("格"+i + j); } } try (OutputStream fileOut = new FileOutputStream(file)) { //获取文件流 fileOut.flush(); wb.write(fileOut); //将workbook写入文件流 } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } return wb; } //创建一个不存在的excel文件 private static Workbook createNewWorkbookIfNotExist(String fileName) throws Exception { Workbook wb = null; if(fileName.endsWith(".xls")) { wb = new HSSFWorkbook(); } else if(fileName.endsWith(".xlsx")) { wb = new XSSFWorkbook(); } else { throw new Exception("文件类型错误！既不是.xls也不是.xlsx"); } try{ OutputStream output = new FileOutputStream(fileName); wb.write(output); }catch(FileNotFoundException e) { System.out.println("文件创建失败，失败原因为：" + e.getMessage()); throw new FileNotFoundException(); } System.out.println(fileName + "文件创建成功！"); return wb; } //创建一个新的或者已存在的Excel文档的Workbook public static Workbook createWorkbook(String fileName) throws Exception { InputStream input = null; Workbook wb = null; try{ input = new FileInputStream(fileName); wb = WorkbookFactory.create(input); if (!new File(fileName).exists()){ //如果不存在 wb = createNewWorkbookIfNotExist(fileName); //创建新的 } } catch(OldExcelFormatException e) { System.out.println("文件打开失败，原因：要打开的Excel文件版本过低！"); throw new OldExcelFormatException("文件版本过低"); } finally { if(input != null) { input.close(); } } return wb; } //创建sheet public static Sheet createSheet(Workbook wb , String sheetName) { Sheet sheet = wb.getSheet(sheetName); if(sheet == null) { System.out.println("表单" + sheetName + "不存在，试图创建该sheet，请稍后……"); sheet = wb.createSheet(sheetName); System.out.println("名为" + sheetName +"的sheet创建成功！"); } return sheet; } //创建行row public static Row createRow(Sheet sheet , int rowNum) { Row row = sheet.getRow(rowNum); if(row == null) { System.out.println("行号为：" + rowNum + "的行不存在，正试图创建该行，请稍后……"); row = sheet.createRow(rowNum); System.out.println("行号为：" + rowNum + "的行创建成功！"); } return row; } //创建单元格cell public static Cell createCell(Row row , int cellNum) { Cell cell = row.getCell(cellNum); if(cell == null) { System.out.println("该单元格不存在，正在试图创建该单元格，请稍后……"); cell = row.createCell(cellNum); System.out.println("该单元格创建成功！"); } return cell; } /** * 追加到已有excel * @param dataList 数据 * @param name 文件名 */ public static void addExcel(List<LinkedHashMap<String,Object>> dataList, String name) throws IOException { FileInputStream fileInputStream=new FileInputStream("d://"+name+".xls"); //获取d://test.xls,建立数据的输入通道 POIFSFileSystem poifsFileSystem=new POIFSFileSystem(fileInputStream); //使用POI提供的方法得到excel的信息 HSSFWorkbook Workbook=new HSSFWorkbook(poifsFileSystem);//得到文档对象 HSSFSheet sheet=Workbook.getSheet(name); //根据name获取sheet表 HSSFCellStyle cellStyle = Workbook.createCellStyle(); /*cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN); //下边框 cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);//左边框 cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);//上边框 cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);//右边框 cellStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER); // 居中*/ // HSSFRow row=sheet.getRow(0); //获取第一行 System.out.println("最后一行的行号 :"+sheet.getLastRowNum() + 1); //分别得到最后一行的行号，和第3条记录的最后一个单元格 //System.out.println("最后一个单元格 :"+row.getLastCellNum()); //分别得到最后一行的行号，和第3条记录的最后一个单元格 // HSSFRow startRow=sheet.createRow((short)(sheet.getLastRowNum()+1)); // 追加开始行 // -----------------追加数据------------------- int start = sheet.getLastRowNum() + 1; //插入数据开始行 for (int i = 0; i < dataList.size(); i++){ HSSFRow startRow = sheet.createRow(i+start); AtomicInteger j = new AtomicInteger(); LinkedHashMap<String ,Object> ltem = dataList.get(i); } // 输出Excel文件 FileOutputStream out=new FileOutputStream("d://"+name+".xls"); //向d://test.xls中写数据 out.flush(); Workbook.write(out); out.close(); } public static void readExcel(String name) throws IOException { FileInputStream fileInputStream=new FileInputStream("d:\\"+name+".xls"); //获取d://test.xls,建立数据的输入通道 POIFSFileSystem poifsFileSystem=new POIFSFileSystem(fileInputStream); //使用POI提供的方法得到excel的信息 HSSFWorkbook Workbook=new HSSFWorkbook(poifsFileSystem);//得到文档对象 HSSFSheet sheet=Workbook.getSheet(name); //根据name获取sheet表 HSSFRow row=sheet.getRow(1); //获取第二行（第一行一般是标题） int lastRow = sheet.getLastRowNum(); // 返回的是值从0开始的 System.out.println("总行数：" + (lastRow + 1)); int lastCell = row.getLastCellNum(); // 返回的值是从1开始的..... System.out.println("总列数：" + lastCell); for (int i = 0; i <= lastRow; i++){ row=sheet.getRow(i); if (row != null){ for (int j = 0; j < lastCell; j++){ HSSFCell cell = row.getCell(j); if (cell != null) System.out.println(cell.getStringCellValue()); } } } }
代码