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 block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.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 block
					e.printStackTrace();
				} catch (NoSuchMethodException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IllegalArgumentException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (IllegalAccessException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				} catch (InvocationTargetException e) {
					// TODO Auto-generated catch block
					e.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 block
			e.printStackTrace();
		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}