使用POI生成Excel文件

Apache POI 是用Java编写的免费开源的跨平台的 Java API，提供对Microsoft Office格式档案读和写的功能。

使用POI导出EXCEL的例子很多，这里列出一个比较完善的实例 http://blog.csdn.net/xw13106209/article/details/6619092

我在此例子上进行了改造，实现了在一个Excel文件中保存两个Sheet。

方法很简单：在写第一个Sheet时新建一个工作薄HSSFWorkbook workbook = new HSSFWorkbook();

                        在写第二个Sheet时打开创建好的工作薄InputStream myxls = new FileInputStream(fileName);  HSSFWorkbook workbook = new HSSFWorkbook(myxls);

                        然后就都一样了，生成表格写数据。

具体代码如下：

public class ExportExcelTwoSheet<T> {// public void exportExcel(String title, Collection<T> dataset, OutputStream// out) {// exportExcel(title, null, dataset, out, "yyyy-MM-dd");// }public void exportExcel(String title, String[] headers, Collection<T> dataset, String fileName, String type) {try {exportExcel(title, headers, dataset, fileName, "yyyy-MM-dd", type);} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}// public void exportExcel(String[] headers, Collection<T> dataset,// OutputStream out, String pattern) {// exportExcel("测试POI导出EXCEL文档", headers, dataset, out, pattern);// }/** * 这是一个通用的方法，利用了JAVA的反射机制，可以将放置在JAVA集合中并且符号一定条件的数据以EXCEL 的形式输出到指定IO设备上 *  * @param title *            表格标题名 * @param headers *            表格属性列名数组 * @param dataset *            需要显示的数据集合,集合中一定要放置符合javabean风格的类的对象。此方法支持的 *            javabean属性的数据类型有基本数据类型及String,Date,byte[](图片数据) * @param out *            与输出设备关联的流对象，可以将EXCEL文档导出到本地文件或者网络中 * @param pattern *            如果有时间数据，设定输出格式。默认为"yyy-MM-dd" * @throws IOException * @throws FileNotFoundException */@SuppressWarnings("unchecked")public void exportExcel(String title, String[] headers, Collection<T> dataset, String fileName, String pattern, String type)throws FileNotFoundException, IOException {// 声明一个工作薄HSSFWorkbook workbook = null;if (type.equals("new")) {workbook = new HSSFWorkbook();} else if (type.equals("add")) {InputStream myxls = new FileInputStream(fileName);workbook = new HSSFWorkbook(myxls);myxls.close();}// 生成一个表格HSSFSheet sheet = workbook.createSheet(title);// 设置表格默认列宽度为15个字节sheet.setDefaultColumnWidth((short) 15);// 生成一个样式HSSFCellStyle style = workbook.createCellStyle();// 设置这些样式style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);style.setBorderBottom(HSSFCellStyle.BORDER_THIN);style.setBorderLeft(HSSFCellStyle.BORDER_THIN);style.setBorderRight(HSSFCellStyle.BORDER_THIN);style.setBorderTop(HSSFCellStyle.BORDER_THIN);style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 生成一个字体HSSFFont font = workbook.createFont();font.setColor(HSSFColor.VIOLET.index);font.setFontHeightInPoints((short) 12);font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);// 把字体应用到当前的样式style.setFont(font);// 生成并设置另一个样式HSSFCellStyle style2 = workbook.createCellStyle();style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);style2.setBorderRight(HSSFCellStyle.BORDER_THIN);style2.setBorderTop(HSSFCellStyle.BORDER_THIN);style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 生成另一个字体HSSFFont font2 = workbook.createFont();font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);// 把字体应用到当前的样式style2.setFont(font2);// 声明一个画图的顶级管理器HSSFPatriarch patriarch = sheet.createDrawingPatriarch();// 定义注释的大小和位置,详见文档HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0, 0, 0, 0, (short) 4, 2, (short) 6, 5));// 设置注释内容comment.setString(new HSSFRichTextString("可以在POI中添加注释！"));// 设置注释作者，当鼠标移动到单元格上是可以在状态栏中看到该内容.comment.setAuthor("leno");// 产生表格标题行HSSFRow row = sheet.createRow(0);for (short i = 0; i < headers.length; i++) {HSSFCell cell = row.createCell(i);cell.setCellStyle(style);HSSFRichTextString text = new HSSFRichTextString(headers[i]);cell.setCellValue(text);}// 遍历集合数据，产生数据行Iterator<T> it = dataset.iterator();int index = 0;while (it.hasNext()) {index++;row = sheet.createRow(index);T t = (T) it.next();// 利用反射，根据javabean属性的先后顺序，动态调用getXxx()方法得到属性值Field[] fields = t.getClass().getDeclaredFields();for (short i = 0; i < fields.length; i++) {HSSFCell cell = row.createCell(i);cell.setCellStyle(style2);Field field = fields[i];String fieldName = field.getName();String getMethodName = "get" + fieldName.substring(0, 1).toUpperCase() + fieldName.substring(1);try {Class tCls = t.getClass();Method getMethod = tCls.getMethod(getMethodName, new Class[] {});Object value = getMethod.invoke(t, new Object[] {});// 判断值的类型后进行强制类型转换String textValue = null;// if (value instanceof Integer) {// int intValue = (Integer) value;// cell.setCellValue(intValue);// } else if (value instanceof Float) {// float fValue = (Float) value;// textValue = new HSSFRichTextString(// String.valueOf(fValue));// cell.setCellValue(textValue);// } else if (value instanceof Double) {// double dValue = (Double) value;// textValue = new HSSFRichTextString(// String.valueOf(dValue));// cell.setCellValue(textValue);// } else if (value instanceof Long) {// long longValue = (Long) value;// cell.setCellValue(longValue);// }if (value instanceof Boolean) {boolean bValue = (Boolean) value;textValue = "男";if (!bValue) {textValue = "女";}} else if (value instanceof Date) {Date date = (Date) value;SimpleDateFormat sdf = new SimpleDateFormat(pattern);textValue = sdf.format(date);} else if (value instanceof byte[]) {// 有图片时，设置行高为60px;row.setHeightInPoints(60);// 设置图片所在列宽度为80px,注意这里单位的一个换算sheet.setColumnWidth(i, (short) (35.7 * 80));// sheet.autoSizeColumn(i);byte[] bsValue = (byte[]) value;HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0, 1023, 255, (short) 6, index, (short) 6, index);anchor.setAnchorType(2);patriarch.createPicture(anchor, workbook.addPicture(bsValue, HSSFWorkbook.PICTURE_TYPE_JPEG));} else {// 其它数据类型都当作字符串简单处理textValue = value.toString();}// 如果不是图片数据，就利用正则表达式判断textValue是否全部由数字组成if (textValue != null) {Pattern p = Pattern.compile("^//d+(//.//d+)?{1}");Matcher matcher = p.matcher(textValue);if (matcher.matches()) {// 是数字当作double处理cell.setCellValue(Double.parseDouble(textValue));} else {HSSFRichTextString richString = new HSSFRichTextString(textValue);HSSFFont font3 = workbook.createFont();font3.setColor(HSSFColor.BLUE.index);richString.applyFont(font3);cell.setCellValue(richString);}}} catch (SecurityException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (NoSuchMethodException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalArgumentException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (InvocationTargetException e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {// 清理资源}}}OutputStream out = null;try {out = new FileOutputStream(fileName);workbook.write(out);} catch (IOException e) {e.printStackTrace();}finally {if (out != null) {try {out.close();} catch (IOException e) {e.printStackTrace();}}}}public static void main(String[] args) {// 测试学生ExportExcelTwoSheet<Student> ex = new ExportExcelTwoSheet<Student>();String[] headers = { "学号", "姓名", "年龄", "性别", "出生日期" };List<Student> dataset = new ArrayList<Student>();dataset.add(new Student(10000001, "张三", 20, true, new Date()));dataset.add(new Student(20000002, "李四", 24, false, new Date()));dataset.add(new Student(30000003, "王五", 22, true, new Date()));// 测试图书ExportExcelTwoSheet<Book> ex2 = new ExportExcelTwoSheet<Book>();String[] headers2 = { "图书编号", "图书名称", "图书作者", "图书价格", "图书ISBN", "图书出版社", "封面图片" };List<Book> dataset2 = new ArrayList<Book>();try {BufferedInputStream bis = new BufferedInputStream(new FileInputStream("book.jpg"));byte[] buf = new byte[bis.available()];while ((bis.read(buf)) != -1) {//}dataset2.add(new Book(1, "jsp", "leno", 300.33f, "1234567", "清华出版社", buf));dataset2.add(new Book(2, "java编程思想", "brucl", 300.33f, "1234567", "阳光出版社", buf));dataset2.add(new Book(3, "DOM艺术", "lenotang", 300.33f, "1234567", "清华出版社", buf));dataset2.add(new Book(4, "c++经典", "leno", 400.33f, "1234567", "清华出版社", buf));dataset2.add(new Book(5, "c#入门", "leno", 300.33f, "1234567", "汤春秀出版社", buf));String fileName = "E://all.xls";ex.exportExcel("Student", headers, dataset, fileName, "new");ex2.exportExcel("Book", headers2, dataset2, fileName, "add");JOptionPane.showMessageDialog(null, "导出成功!");System.out.println("excel导出成功！");} catch (FileNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}}