比较常用的文件处理类

package com.aijia.util;
/**
* 一些文件处理
*/

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.util.Log;
import android.widget.ImageView;

public class FileUtil {
/**
* 显示图片的缩略图
*
* @param uri  图片路径
* @param size图片比例
* @return
*/
public static Bitmap getOpBitmap(String uri, int size) {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;

Bitmap bitmap = BitmapFactory.decodeFile(uri, options);

options.inJustDecodeBounds = false;

int be = (int) (options.outHeight / (float) size);

if (be <= 0)
be = 1;
options.inSampleSize = be;
options.inPreferredConfig = Bitmap.Config.RGB_565;
File file = new File(uri);
InputStream in = null;
try {
in = new FileInputStream(file);

} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
if (in != null) {
bitmap = BitmapFactory.decodeStream(in, null, options);
try {
in.close();
} catch (IOException e) {

e.printStackTrace();
}
}

// bitmap = BitmapFactory.decodeFile(uri, options);
return bitmap;
}

/**
* 删除文件夹
*
* @param folderPath
*/
public static void delFolder(String folderPath) {
try {
delAllFile(folderPath); // 删除完里面所有内容
String filePath = folderPath;
filePath = filePath.toString();
java.io.File myFilePath = new java.io.File(filePath);
myFilePath.delete(); // 删除空文件夹

} catch (Exception e) {
System.out.println("删除文件夹操作出错");
e.printStackTrace();

}
}
/**
* 删除所有文件
* @param path
*/

public static void delAllFile(String path) {
File file = new File(path);
if (!file.exists()) {
return;
}
if (!file.isDirectory()) {
return;
}
String[] tempList = file.list();
File temp = null;
for (int i = 0; i < tempList.length; i++) {
if (path.endsWith(File.separator)) {
temp = new File(path + tempList[i]);
} else {
temp = new File(path + File.separator + tempList[i]);
}
if (temp.isFile()) {
temp.delete();
}
if (temp.isDirectory()) {
delAllFile(path + "/" + tempList[i]);// 先删除文件夹里面的文件
delFolder(path + "/" + tempList[i]);// 再删除空文件夹
}
}
}

/**
* 判断指定路徑的文件是否存在
*
* @param path
* @return
*/
public static boolean existFile(String path) {
File file = new File(path);
if (file.exists()) {
return true;
} else {
return false;
}

}

/**
* 如果给定路径不存在这个文件夹，创建文件夹
*
* @param path
*/
public static void createFolder(String path) {
File file = new File(path);
if (!file.exists()) {
file.mkdirs();
}

}
/**
* 如果給定路徑存在這個文件，刪除這個文件
* @param path
*/
public static void deleteFile(String path) {
File file = new File(path);
if (file.exists()) {
file.delete();
}

}

/**
* 下载图片到本地
*
* @param urlPath
* @param savePath
* @throws Exception
*/
public static void downloadImg(String urlPath, String savePath)
throws Exception {// 获取图片
if (!existFile(savePath)) {//如果不存在这个文件

String folderpath = savePath
.substring(0, savePath.lastIndexOf("/"));
createFolder(folderpath);//创建相应的文件夹

String str = java.net.URLEncoder.encode(urlPath, "UTF-8");
str = str.replaceAll("%2F", "/");// 需要把网址的特殊字符转过来
str = str.replaceAll("%3A", ":");

URL url = new URL(str);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(3 * 1000);
if (conn.getResponseCode() == 200) {
InputStream inSream = conn.getInputStream();
File file = new File(savePath);

FileOutputStream outStream = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = -1;
while ((len = inSream.read(buffer)) != -1) {
outStream.write(buffer, 0, len);
}
outStream.close();
inSream.close();

}

}

}
}