public static String getParent(String filePath, int level) {
		final File parent = getParent(file(filePath), level);
		try {
			return null == parent ? null : parent.getCanonicalPath();
		} catch (IOException e) {
			throw new IORuntimeException(e);
		}
	}
@Test
	public void getParentTest() {
		// 只在Windows下测试
		if (FileUtil.isWindows()) {
			File parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 0);
			assertEquals(FileUtil.file("d:\\aaa\\bbb\\cc\\ddd"), parent);

			parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 1);
			assertEquals(FileUtil.file("d:\\aaa\\bbb\\cc"), parent);

			parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 2);
			assertEquals(FileUtil.file("d:\\aaa\\bbb"), parent);

			parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 4);
			assertEquals(FileUtil.file("d:\\"), parent);

			parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 5);
			assertNull(parent);

			parent = FileUtil.getParent(FileUtil.file("d:/aaa/bbb/cc/ddd"), 10);
			assertNull(parent);
		}
	}