Android外置存储器（SD卡）工具种

/** *  */package com.lurencun.android.util;import java.io.File;import java.io.IOException;import android.os.Environment;/** * @author chenyoca [桥下一粒砂] ([email protected]) * @date 2011-12-8 * @desc 外置存储器（通常是SD卡）辅助使用类 */public class ExternalStorager {	private static final String STATE = Environment.getExternalStorageState();	private static final String MKDIR_MSG = "Cannot make diretory on external storager ! It might be your application have no permission to write on external storager .";	private static final String STORAGER_NOT_READY_MSG = "External storager do not ready to rw !";	public static final String TAG = "SDCardLOG";		/**	 * 判断外置存储器是否已经就绪。就绪状态是指外置存储器已经挂载并且系统拥有对其可读可写权限。	 * @return 就绪则返回true，否则返回false。	 */	public static boolean isExternalStorageReady() {		return Environment.MEDIA_MOUNTED.equals(STATE);	}	/**	 * 在外置存储器中创建目录。	 * @param folder 需要创建外置存储器中的目录路径	 * @return 如果创建成功或者已经存在，返回目录的完整路径(路径末尾包括File.separator符号“/”)。	 * @throws IOException 当外置存储器未就绪，或者写入外置存储器失败（可能是应该没有读写权限）时，抛出此异常。	 */	public static String mkdir(String folder) throws IOException {		String _storage_path = getExternalStoragePath();		if (null == _storage_path) throw new IOException(STORAGER_NOT_READY_MSG);		StringBuffer _path = new StringBuffer(_storage_path);		if(!folder.startsWith(File.separator)) _path.append(File.separator);		_path.append(folder);		if(!folder.endsWith(File.separator)) _path.append(File.separator);		File _dir = new File(_path.toString());		if(!_dir.exists()){			if(!_dir.mkdirs())throw new IOException(MKDIR_MSG);		}		return _path.toString();	}		/**	 * 获取外置存储器的路径	 * @return 外置存储器已经就绪，返回其路径，否则返回null。	 */	public static String getExternalStoragePath() {		String _path = isExternalStorageReady() ? 				Environment.getExternalStorageDirectory().getPath() : null;		return _path;	}}