数据库拷贝到本地 sqlite

private void copyDB(){
    File dbFile = new File(Environment.getDataDirectory().getAbsolutePath()+"/data/com.example.main/databases/mydb.db");
    FileInputStream fis = null;
    FileOutputStream fos = null;
    try {
        fis = new FileInputStream(dbFile);
        fos = new FileOutputStream(Environment.getExternalStorageDirectory().getAbsolutePath()+"/copy.db");
        int len = 0;
        byte[] buffer = new byte[2048];
        while(-1!=(len=fis.read(buffer))){
            fos.write(buffer, 0, len);
        }
        fos.flush();

    } catch (Exception e) {
        e.printStackTrace();
    }finally{
        try{
            if(fos!=null)fos.close();
            if (fis!=null)fis.close();
        }catch(IOException e){
            e.printStackTrace();
        }
    }
}