FileUtil.java

package com.keju.maomao.util;

import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.text.DecimalFormat;

import android.content.Context;

/**
 * 文件处理工具类
 * 
 * @author Zhoujun
 * 
 */
public class FileUtil {
	/**
	 * 读取assets下的文本数据
	 * 
	 * @param fileName
	 * @return
	 */
	public static String getStringFromAssets(Context context, String fileName) {
		try {
			InputStreamReader inputReader = new InputStreamReader(context.getResources().getAssets().open(fileName));
			BufferedReader bufReader = new BufferedReader(inputReader);
			String line = "";
			String Result = "";
			while ((line = bufReader.readLine()) != null)
				Result += line;
			return Result;
		} catch (Exception e) {
			e.printStackTrace();
		}
		return null;
	}

	/**
	 * 读取文本流文件
	 * 
	 * @param is
	 * @return
	 */
	public static String readStream(InputStream is) {
		try {
			ByteArrayOutputStream bo = new ByteArrayOutputStream();
			int i = is.read();
			while (i != -1) {
				bo.write(i);
				i = is.read();
			}
			return bo.toString();
		} catch (IOException e) {
			return "";
		}
	}

	/**
	 * 获得文件大小
	 * 
	 * @param filePath
	 * @return
	 * @throws IOException
	 */
	public static long getFileSize(File f) throws IOException {
		long s = 0;
		if (f.exists()) {
			FileInputStream fis = null;
			fis = new FileInputStream(f);
			s = fis.available();
		}
		return s;
	}

	/**
	 * 格式化文件大小
	 * 
	 * @param fileS
	 * @return
	 * @throws IOException
	 */
	public static String formatFileSize(File f) {// 转换文件大小
		String fileSizeString = "";
		try {
			long fileS = getFileSize(f);
			DecimalFormat df = new DecimalFormat("#.00");
			if (fileS < 1024) {
				fileSizeString = df.format((double) fileS) + "b";
			} else if (fileS < 1048576) {
				fileSizeString = df.format((double) fileS / 1024) + "kb";
			} else if (fileS < 1073741824) {
				fileSizeString = df.format((double) fileS / 1048576) + "mb";
			} else {
				fileSizeString = df.format((double) fileS / 1073741824) + "gb";
			}
		} catch (Exception e) {
		}
		return fileSizeString;
	}

	/**
	 * 拷贝资源文件到sd卡
	 * 
	 * @param context
	 * @param resId
	 * @param databaseFilename
	 *            如数据库文件拷贝到sd卡中
	 */
	public static void copyResToSdcard(Context context, int resId, String databaseFilename) {// name为sd卡下制定的路径
		try {
			// 不存在得到数据库输入流对象
			InputStream is = context.getResources().openRawResource(resId);
			// 创建输出流
			FileOutputStream fos = new FileOutputStream(databaseFilename);
			// 将数据输出
			byte[] buffer = new byte[8192];
			int count = 0;
			while ((count = is.read(buffer)) > 0) {
				fos.write(buffer, 0, count);
			}
			// 关闭资源
			fos.close();
			is.close();
		} catch (Exception e) {
		}
	}

	/**
	 * 递归删除某个目录下所有文件；
	 */
	public static Boolean deleteFiles(File file) {
		if (file.isFile() || file.list().length == 0) {
//			file.delete();
		} else {
			if (file.length() != 0) {
				File[] files = file.listFiles();
				for (File f : files) {
					deleteFiles(f);
					f.delete();
				}
//				file.delete();
			} else {
				return false;
			}
		}
		return true;
	}

}