一个关于图片存储，操作SD卡的工具类

package com.yzxy.tool;

import java.io.BufferedInputStream;

import java.io.BufferedOutputStream;

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.io.OutputStream;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;

public class FileUtils {

    private String SDCardRoot;
    private String SDStateString ;
    private final static String ALBUM_PATH  = Environment.getExternalStorageDirectory() + "/yueqiu/";
    
    public FileUtils() 
    {
        //得到当前外部存储设备的目录
        SDCardRoot = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator;
        // 获取扩展SD卡设备状态
        SDStateString = Environment.getExternalStorageState();

    }



public File createFileInSDCard(String dir ,String fileName) throws IOException {

File file = new File(SDCardRoot+ dir + File.separator + fileName);

file.createNewFile();

return file;

}



public File creatSDDir(String dir) {

File dirFile = new File(SDCardRoot + dir + File.separator);

if( !dirFile.exists() ){

dirFile.mkdirs();

}

return dirFile;

}


public boolean isFileExist(String fileName){

File file = new File(ALBUM_PATH + fileName);

return file.exists();

}



public String getFilePath(String dir,String fileName){

return SDCardRoot + dir + File.separator + fileName;

}



public long getSDAvailableSize(){

if (SDStateString.equals(android.os.Environment.MEDIA_MOUNTED)) {

// 取得sdcard文件路径

File pathFile = android.os.Environment.getExternalStorageDirectory();

android.os.StatFs statfs = new android.os.StatFs(pathFile.getPath());

// 获取SDCard上每个block的SIZE

long nBlocSize = statfs.getBlockSize();

// 获取可供程序使用的Block的数量

long nAvailaBlock = statfs.getAvailableBlocks();

// 计算 SDCard 剩余大小Byte

long nSDFreeSize = nAvailaBlock * nBlocSize ;

return nSDFreeSize;

}

return 0;

}


public boolean write2SD(String dir,String fileName,byte[] bytes){

if(bytes == null ){

return false;

}

OutputStream output = null;

try {

// 拥有可读可写权限，并且有足够的容量

if (SDStateString.equals(android.os.Environment.MEDIA_MOUNTED) && bytes.length < getSDAvailableSize() ) {

File file = null;

creatSDDir(dir);

file = createFileInSDCard(dir,fileName);

output = new BufferedOutputStream(new FileOutputStream(file));

output.write(bytes);

output.flush();

return true;

}

} catch (IOException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}finally{

try{

if( output != null ){

output.close();

}

}

catch(Exception e){

e.printStackTrace();

}

}

return false;

}

public Bitmap readbitmap(String path)
{
    File file = new File(ALBUM_PATH+path);
    BitmapFactory.Options opt = new BitmapFactory.Options();
     if( !file.exists() )
     {
             return null;
     }
     InputStream inputStream = null;

     try 
     {
             inputStream = new BufferedInputStream(new FileInputStream(file));           
           opt.inPreferredConfig = Bitmap.Config.RGB_565;   
           opt.inPurgeable = true;  
           opt.inInputShareable = true;  
     }
     catch (FileNotFoundException e) 
     {
             e.printStackTrace();
     } catch (IOException e)
     {
             e.printStackTrace();

     }
//    Bitmap bit = BitmapFactory.decodeFile(ALBUM_PATH+path);
//    return bit;
     return BitmapFactory.decodeStream(inputStream,null,opt);
}

 public byte[] readFromSD(String dir,String fileName)
 {

     File file = new File(SDCardRoot + dir + File.separator + fileName);

     if( !file.exists() ){

             return null;

     }

     InputStream inputStream = null;

     try {

         inputStream = new BufferedInputStream(new FileInputStream(file));

         byte[] data = new byte[inputStream.available()];

         inputStream.read(data);

         return data;

         } catch (FileNotFoundException e) 
         {
             e.printStackTrace();
         } catch (IOException e)
         {
             e.printStackTrace();

         }finally{

             try {

                 if( inputStream != null ){

                     inputStream.close();

                 }

         } catch (IOException e) {

// TODO Auto-generated catch block

             e.printStackTrace();

         }

         }

         return null;

 }


public File write2SDFromInput(String dir,String fileName,InputStream input){

File file = null;

OutputStream output = null;

try {

int size = input.available();

// 拥有可读可写权限，并且有足够的容量

if (SDStateString.equals(android.os.Environment.MEDIA_MOUNTED) && size < getSDAvailableSize() ) {

creatSDDir(dir);

file = createFileInSDCard(dir,fileName);

output = new BufferedOutputStream(new FileOutputStream(file));

byte buffer [] = new byte[4*1024];

int temp ;

while((temp = input.read(buffer)) != -1){

output.write(buffer,0,temp);

}

output.flush();

}

} catch (IOException e1) {

// TODO Auto-generated catch block

e1.printStackTrace();

}finally{

try{

if( output != null ){

output.close();

}

}

catch(Exception e){

e.printStackTrace();

}

}

return file;

}


public void saveFile(Bitmap bm, String fileName) throws IOException {   
    File dirFile = new File(ALBUM_PATH); 
    fileName=fileName.replace("/", "_");
    if(!dirFile.exists())
    {   
        dirFile.mkdir();   
    }   
    File myCaptureFile = new File(ALBUM_PATH + fileName);   
    BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(myCaptureFile));   
    bm.compress(Bitmap.CompressFormat.JPEG, 80, bos);   
    bos.flush();   
    bos.close(); 
    System.out.println("保存成功");
}
}