poi 三层表头

		// TODO Auto-generated method stub
		FileOutputStream fileOut = null;
		File file = new File("c:/1.xls");
		String[] header = { "服务器名", "IP地址", "库cache命中率_最大值", "库cache命中率_平均值",
				"连接数_最大值", "连接数_平均值", "游标数_最大值", "游标数_平均值", "session数_最大值",
				"session数_平均值", "事务数_最大值", "事务数_平均值", "数据库锁数_最大值", "数据库锁数_平均值",
				"缓冲池命中数_最大值", "缓冲池命中数_平均值", "表空间_使用率_最大值", "表空间_使用率_平均值",
				"表空间_已用空间_最大值", "表空间_已用空间_平均值", "表空间_剩余率_最大值", "表空间_剩余率_平均值",
				"表空间_剩余空间_最大值", "表空间_剩余空间_平均值", "表空间_总容量_最大值", "表空间_总容量_平均值",
				"连接状态" };
		try {
			HSSFWorkbook wb = new HSSFWorkbook();
			HSSFSheet sheet = wb.createSheet("new sheet");
			HSSFFont fontinfo = wb.createFont();
			fontinfo.setFontHeightInPoints((short) 8); // 字体大小
			HSSFFont fonthead = wb.createFont();
			fonthead.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);// 加粗
			HSSFCellStyle cellStylename = wb.createCellStyle();// 表名样式
			cellStylename.setFont(fonthead);
			HSSFCellStyle cellStyleinfo = wb.createCellStyle();// 表信息样式
			cellStyleinfo.setAlignment(HSSFCellStyle.ALIGN_RIGHT);// 对齐
			cellStyleinfo.setFont(fontinfo);
			HSSFCellStyle cellStylehead = wb.createCellStyle();// 表头样式
			cellStylehead.setFont(fonthead);
			cellStylehead.setAlignment(HSSFCellStyle.ALIGN_CENTER);
			cellStylehead.setBorderBottom(HSSFCellStyle.BORDER_THIN);// 边框
			cellStylehead.setBottomBorderColor(HSSFColor.BLACK.index);
			cellStylehead.setBorderLeft(HSSFCellStyle.BORDER_THIN);
			cellStylehead.setLeftBorderColor(HSSFColor.BLACK.index);
			cellStylehead.setBorderRight(HSSFCellStyle.BORDER_THIN);
			cellStylehead.setRightBorderColor(HSSFColor.BLACK.index);
			cellStylehead.setBorderTop(HSSFCellStyle.BORDER_THIN);
			cellStylehead.setTopBorderColor(HSSFColor.BLACK.index);
			cellStylehead.setFillForegroundColor(HSSFColor.ORANGE.index);
			cellStylehead.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
			HSSFCellStyle cellStyle = wb.createCellStyle();// 数据单元样式
			cellStyle.setWrapText(true);// 自动换行
			cellStyle.setBorderBottom(HSSFCellStyle.BORDER_THIN);
			cellStyle.setBottomBorderColor(HSSFColor.BLACK.index);
			cellStyle.setBorderLeft(HSSFCellStyle.BORDER_THIN);
			cellStyle.setLeftBorderColor(HSSFColor.BLACK.index);
			cellStyle.setBorderRight(HSSFCellStyle.BORDER_THIN);
			cellStyle.setRightBorderColor(HSSFColor.BLACK.index);
			cellStyle.setBorderTop(HSSFCellStyle.BORDER_THIN);
			cellStyle.setTopBorderColor(HSSFColor.BLACK.index);
			
			int col = header.length;
			HSSFRow row = sheet.createRow((short) 0);
			HSSFCell cell = row.createCell((short) 0);
			cell.setEncoding(HSSFCell.ENCODING_UTF_16);
			cell.setCellStyle(cellStylename);
			cell.setCellValue("oracle");// 表名
			sheet.addMergedRegion(new Region(0, (short) 0, 0, (short) 1));

			cell = row.createCell((short) 2);
			cell.setEncoding(HSSFCell.ENCODING_UTF_16);
			cell.setCellStyle(cellStyleinfo);
			cell.setCellValue("oracle"); // 信息
			sheet.addMergedRegion(new Region(0, (short) 2, 0, (short) col));

			int rows_max = 0;
			for (int i = 0; i < header.length; i++) {
				String h = header[i];
				if (h.split("_").length > rows_max) {
					rows_max = h.split("_").length;
				}
			}
			Map map = new HashMap();
			for (int k = 0; k < rows_max; k++) {
				row = sheet.createRow((short) k + 1);
				if (k == 0) {
					cell = row.createCell((short) (0));
					cell.setEncoding(HSSFCell.ENCODING_UTF_16);
					cell.setCellStyle(cellStylehead);
					cell.setCellValue("序号");
					sheet.addMergedRegion(new Region(k + 1, (short) 0, k
							+ rows_max, (short) 0));
				}
				for (int i = 0; i < header.length; i++) {
					String headerTemp = header[i];
					String[] s = headerTemp.split("_");
					String sk = "";
					int num = i + 1;
					if (s.length == 1) {
						cell = row.createCell((short) (num));
						cell.setEncoding(HSSFCell.ENCODING_UTF_16);
						cell.setCellStyle(cellStylehead);
						sheet.addMergedRegion(new Region(1, (short) (num),
								rows_max, (short) (num)));
						sk = headerTemp;
						cell.setCellValue(sk);
					} else {
						System.out.println(sk);
						
						cell = row.createCell((short) (num));
						cell.setEncoding(HSSFCell.ENCODING_UTF_16);
						cell.setCellStyle(cellStylehead);
						int cols = 0;
						if (map.containsKey(headerTemp)) {
							continue;
						}
						for (int d = 0; d <= k; d++) {
							if (d != k) {
								sk += s[d] + "_";
							} else{
								sk += s[d];
							}
						}
						if(map.containsKey(sk)){
							continue;
						}
						for (int j = 0; j < header.length; j++) {
							if (header[j].indexOf(sk) != -1) {
								cols++;
							}
						}
						cell.setCellValue(s[k]);
						sheet
								.addMergedRegion(new Region(k + 1,
										(short) num, k + 1,
										(short) (num + cols-1)));
						if (sk.equals(headerTemp)) {
							sheet.addMergedRegion(new Region(k + 1,
									(short) num, k + 1 + rows_max
											- s.length, (short) num));
						}
					}
					if (s.length > k) {
						if (!map.containsKey(sk)) {
							String key = "";
							if (k > 0) {
								key = sk;
							} else {
								key = s[k];
							}
							map.put(key, null);
						}
					}
				}
			}
			fileOut = new FileOutputStream(file);
			// modify by xywang(2007-11-19) end
			wb.write(fileOut);
		} catch (Exception e) {
			e.printStackTrace();
		}