java 导入Excel 为 List

用户需求中曾经有写需要把Excel中的数据导入数据库中，不过每次都要一一对应Excel中的数据然后写程序，太繁琐，

后来想了一下，改成这样的，以后就方便导入数据，直接遍历List就可以把数据导入进来了。

/**
	 * 
	 * @param filePath 文件路径
	 * @param clazz 存放的数据是那个对象的数据：类似User.class
	 * @param field 标题中那个标题对应那个对象中的那个字段：map.add("Excel标题", "user的字段值")
	 * @return
	 */
	private static List getExcel(String filePath, Class clazz,
			Map<String, String> field) {
		if (!filePath.endsWith("xls")) {
			System.out.println("文件不是Excel");
			return null;
		}
		List list = new ArrayList();
		Workbook wk = null;
		try {
			wk = Workbook.getWorkbook(new File(filePath));
			Sheet sheet = wk.getSheet(0);
			Map<Integer, String> columnMap = readTitle(field, sheet.getRow(0));
			if (columnMap == null || columnMap.size() == 0) {
				System.out.println("没有查到相应的标题");
				return null;
			}
			for (int i = 1; i < sheet.getRows(); i++) {
				Cell[] cells = sheet.getRow(i);
				if (cells.length == 0)
					continue;
				Set<Map.Entry<Integer, String>> set = columnMap.entrySet();
				Object obj = clazz.newInstance();
				for (Iterator<Map.Entry<Integer, String>> iter = set.iterator(); iter
						.hasNext();) {
					Map.Entry<Integer, String> entry = iter.next();
					String fieldValue = cells[entry.getKey()].getContents()
							.trim();
					String fieldName = entry.getValue();
					invokeMethod(clazz, obj, fieldName, fieldValue);
				}
				list.add(obj);
			}
		} catch (Exception e) {
			e.printStackTrace();
			return null;
		} finally {
			if (wk != null)
				wk.close();
		}
		return list;
	}

	private static Object invokeMethod(Class<?> clazz, Object instance,
			String fileName, String fieldValue) throws Exception {
		Method getMethod = clazz.getMethod("get" + toFirstUpper(fileName));
		Class<?> paraType = getMethod.getReturnType();
		Method setMethod = clazz.getMethod("set" + toFirstUpper(fileName),
				paraType);
		Object value = transfType(paraType, fieldValue);
		if (value != null)
			setMethod.invoke(instance, value);
		return instance;
	}

	private static Object transfType(Class<?> paraType, String target) {
		Object result = null;
		if (paraType == String.class) {
			result = target;
		} else if (paraType == Double.class) {
			result = new Double(Double.parseDouble(target));
		} else if (paraType == double.class) {
			result = Double.parseDouble(target);
		} else if (paraType == boolean.class) {
			result = Boolean.parseBoolean(target);
		} else if (paraType == Boolean.class) {
			result = Boolean.valueOf(target);
		} else if (paraType == int.class) {
			result = Integer.parseInt(target);
		} else if (paraType == Integer.class) {
			result = Integer.decode(target);
		} else if (paraType == long.class) {
			result = Long.parseLong(target);
		} else if (paraType == Long.class) {
			result = Long.decode(target);
		} else if (paraType == float.class) {
			result = Float.parseFloat(target);
		} else if (paraType == Float.class) {
			result = Float.valueOf(target);
		}
		return result;
	}

	public static String toFirstUpper(String str) {
		return str.replaceFirst(str.substring(0, 1), str.substring(0, 1)
				.toUpperCase());
	}

	private static Map<Integer, String> readTitle(Map<String, String> fieldMap,
			Cell[] cells) {
		Map<Integer, String> columnMap = new HashMap<Integer, String>();
		for (int i = 0; i < cells.length; i++) {
			String content = cells[i].getContents().trim();
			String field = fieldMap.get(content);
			if (field != null) {
				columnMap.put(i, field);
			}
		}
		return columnMap;
	}