（转）FileUtil.java 工具类

package com.spring.sky.dialog.download;

import java.io.File;
import java.io.IOException;
import java.sql.Timestamp;
import java.text.DecimalFormat;

import android.content.Context;
import android.os.Environment;
import android.util.Log;

/**
* 文件工具类
* @author spring sky
*
*/
public class FileUtil {
/**
* 获取目录名称
* @param url
* @return FileName
*/
public static String getFileName(String url)
{
int lastIndexStart = url.lastIndexOf("/");
if(lastIndexStart!=-1)
{
return url.substring(lastIndexStart+1, url.length());
}else{
return new Timestamp(System.currentTimeMillis()).toString();
}
}
/**
* 判断SD卡是否存在
* @return boolean
*/
public static boolean checkSDCard() {
if (android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED)) {
return true;
} else {
return false;
}
}

/**
* 保存目录目录到目录
* @param context
* @return  目录保存的目录
*/
public static String setMkdir(Context context)
{
String filePath = null;
if(checkSDCard())
{
filePath = Environment.getExternalStorageDirectory()+File.separator+"yishuabao"+File.separator+"downloads";
}else{
filePath = context.getCacheDir().getAbsolutePath()+File.separator+"yishuabao"+File.separator+"downloads";
}
File file = new File(filePath);
if(!file.exists())
{
file.mkdirs();
Log.e("file", "目录不存在   创建目录    ");
}else{
Log.e("file", "目录存在");
}
return filePath;
}

/**
* 获取路径
* @return
* @throws IOException
*/
public static  String getPath(Context context,String url)
{
String path = null;
try {
path = FileUtil.setMkdir(context)+File.separator+url.substring(url.lastIndexOf("/")+1);
} catch (Exception e) {
e.printStackTrace();
}
return path;
}

/**
* 获取文件的大小
*
* @param fileSize
*            文件的大小
* @return
*/
public static String FormetFileSize(int fileSize) {// 转换文件大小
DecimalFormat df = new DecimalFormat("#.00");
String fileSizeString = "";
if (fileSize < 1024) {
fileSizeString = df.format((double) fileSize) + "B";
} else if (fileSize < 1048576) {
fileSizeString = df.format((double) fileSize / 1024) + "K";
} else if (fileSize < 1073741824) {
fileSizeString = df.format((double) fileSize / 1048576) + "M";
} else {
fileSizeString = df.format((double) fileSize / 1073741824) + "G";
}
return fileSizeString;
}

}