java获取某个目录下的所有文件及文件夹 展示到jsp页面为树形表格

0.前端是用的easyui的treegrid 

<meta http-equiv="X-UA-Compatible" content="IE=9" />
<div class="easyui-layout" fit="true">
  <div region="center" id="FileLog" style="padding:0px;border:0px">
		<table id="test" title="" class="easyui-treegrid" style="width:401px;height:550px"
			url="data\treegrid_data.json"
			rownumbers="true"
			idField="id" treeField="name">
		<thead>
			<tr>
				<th field="name" width="160">名称</th>
				<th field="size" width="100" align="right">大小</th>
				<th field="date" width="110">修改日期</th>
				<div style="margin-left:340px">
					<a href="#" class="easyui-linkbutton" onclick="xiazai()" iconCls="icon-put">下 载</a>
				</div>
			</tr>
		</thead>
	</table>
  </div>
 </div>

第一句代码是为了兼容ie9 url是存放json字符串的文件位置，当时做这个功能的时候，用了这种方式，动态修改json。

1.文件对象 实体类

public class FileObject {
    private  String  id;
    private String name ;
    private String size ;
    private String date ;
    private List<FileObject> children =new ArrayList<FileObject>();
}

2.后台方法（修改json文件）

//获取tomcat所在目录
String Dpath=System.getProperty("catalina.home")+File.separator+"webapps"+File.separator+"fpxtjsp"+File.separator+"file";
File rootFile = new File(Dpath);
File[] fs = rootFile.listFiles();
Arrays.sort(fs);
// 生成的json字符串
String FileString = formatString(rootFile);
// 将字符串写入到指定文件内
try {
	// 存放json字符串的文件夹
	String Parpath = System.getProperty("catalina.home") + File.separator + "webapps" + File.separator + "fpxtjsp" + File.separator + "data";
	File parFile = new File(Parpath);
	// 如果没有文件夹 则创建
	if (!parFile.exists()) {
		parFile.mkdir();
	}
	String dataPath = Parpath + File.separator + "treegrid_data.json";
	File file = new File(dataPath);
	// 如果没有该文件 则创建
	if (!file.exists()) {
		file.createNewFile();
	}
	FileWriter fw = new FileWriter(file.getAbsoluteFile());
	BufferedWriter bw = new BufferedWriter(fw);
	bw.write(FileString);
	bw.close();
} catch (IOException e) {
	// TODO Auto-generated catch block
	e.printStackTrace();
}

3.读取文件夹 转为json字符串 

public static String formatString(File file) {
		FileObject fo = new FileObject();
		fo.setId("");
		fo = getSubFile(file, fo);
		return JSONObject.toJSONString(fo.getChildren());
	}

//递归查找文件夹
public static FileObject getSubFile(File file, FileObject fo) {
		String size = "";
		long fileS = file.length();
		// DecimalFormat df = new DecimalFormat("#.00");
		if (fileS < 1024) {
			size = fileS + "BT";
			// size = df.format((double) fileS) + "BT";
		} else if (fileS < 1048576) {
			size = fileS / 1024 + "KB";
			// size = df.format((double) fileS / 1024) + "KB";
		} else if (fileS < 1073741824) {
			size = fileS / 1048576 + "MB";
			// size = df.format((double) fileS / 1048576) + "MB";
		} else {
			size = fileS / 1073741824 + "GB";
			// size = df.format((double) fileS / 1073741824) +"GB";
		}
		fo.setSize(size);
		fo.setName(file.getName());
		Date date = new Date(file.lastModified());
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd hh:mm");
		fo.setDate(sdf.format(date));
		if (file.isDirectory()) {
			File[] files = file.listFiles();
			Arrays.sort(files, new CompratorByLastModified());
			if (files.length >= 0) {
				for (int i = 0; i < files.length; i++) {
					FileObject subfo = new FileObject();

					subfo.setId(fo.getId() + String.valueOf(i + 1));

					fo.getChildren().add(getSubFile(files[i], subfo));
				}
			}
		}
		return fo;
	}
//根据最后一次修改时间排序
static class CompratorByLastModified implements Comparator<File> {
		public int compare(File f1, File f2) {
			long diff = f1.lastModified() - f2.lastModified();
			if (diff > 0)
				return -1;
			else if (diff == 0)
				return 0;
			else
				return 1;
		}

		public boolean equals(Object obj) {
			return true;
		}
	}