如果要创建文件并多次写入文件并向其添加数据，请使用以下代码，如果不存在则将创建文件，如果存在则将添加数据。

SimpleDateFormat formatter = new SimpleDateFormat("yyyy_MM_dd");

Date now = new Date();

String fileName = formatter.format(now) + ".txt";//like 2016_01_12.txt

try

{

File root = new File(Environment.getExternalStorageDirectory()+File.separator+"Music_Folder", "Report Files");

//File root = new File(Environment.getExternalStorageDirectory(), "Notes");

if (!root.exists())

{

root.mkdirs();

}

File gpxfile = new File(root, fileName);

FileWriter writer = new FileWriter(gpxfile,true);

writer.append(sBody+"\n\n");

writer.flush();

writer.close();

Toast.makeText(this, "Data has been written to Report File", Toast.LENGTH_SHORT).show();

}

catch(IOException e)

{

e.printStackTrace();

}