31 AndroidがSdcardカードからデータを読み込む

/**
	 *  Sdcard       
	 * @param fileName
	 * @return
	 */
	public String readtextFromSdcard(String fileName)
	{
		File root=Environment.getExternalStorageDirectory();
		FileInputStream inputStream=null;
		ByteArrayOutputStream outputStream=new ByteArrayOutputStream();
		String state=Environment.getExternalStorageState();
		if(state.equals(Environment.MEDIA_MOUNTED))
		{
			File file=new File(root.getAbsolutePath()+"/txt");
			File file2=new File(file, fileName);
			int len=0;
			byte[] data=new byte[1024];
			if(file2.exists())
			{
				try {
					inputStream=new FileInputStream(file2);
					while ((len=inputStream.read(data)) != -1) {
			           outputStream.write(data, 0, len);
					}
					return new String(outputStream.toByteArray());
				} catch (Exception e) {
					// TODO: handle exception
					e.printStackTrace();
				}finally{
					if(outputStream != null)
					{
						try {
							outputStream.close();
						} catch (Exception e2) {
							// TODO: handle exception
							e2.printStackTrace();
						}
					}
				}
			}
			
		}
		
		return null;
	}

テストクラスの関連コード:

public void read() {
		FileService service = new FileService();
		String str = service.readtextFromSdcard("aa.txt");
		System.out.println("------>>>>>>>" + str);

	}