访问SDCARD工具类

public class FileUtils {
  private String SDPATH;

  public String getSDPATH() {
   return SDPATH;
  }
  public FileUtils() {
   //得到当前外部存储设备的目录
   // /SDCARD
   SDPATH = Environment.getExternalStorageDirectory() + "/";
  }
  /**
   * 在SD卡上创建文件
   *
   * @throws IOException
   */
  public File creatSDFile(String fileName) throws IOException {
   File file = new File(SDPATH + fileName);
   file.createNewFile();
   return file;
  }
  
  /**
   * 在SD卡上创建目录
   *
   * @param dirName
   */
  public File creatSDDir(String dirName) {
   File dir = new File(SDPATH + dirName);
   dir.mkdir();
   return dir;
  }

  /**
   * 判断SD卡上的文件夹是否存在
   */
  public boolean isFileExist(String fileName){
   File file = new File(SDPATH + fileName);
   return file.exists();
  }
  
  /**
   * 将一个InputStream里面的数据写入到SD卡中
   */
  public File write2SDFromInput(String path,String fileName,InputStream input){
   File file = null;
   OutputStream output = null;
   try{
    creatSDDir(path);
    file = creatSDFile(path + fileName);
    output = new FileOutputStream(file);
    byte buffer [] = new byte[4 * 1024];
    while((input.read(buffer)) != -1){
     output.write(buffer);
    }
    output.flush();
   }
   catch(Exception e){
    e.printStackTrace();
   }
   finally{
    try{
     output.close();
    }
    catch(Exception e){
     e.printStackTrace();
    }
   }
   return file;
  }

 }