public List<Message> queryMessageList(String command,String description ){
??DBAccess dbAccess = new DBAccess();
??SqlSession sqlSession = null;
??List<Message> list = new ArrayList<Message>();
??try {
???dbAccess.getSqlSession();
???//通過sqlSession執行sql語句
???list = sqlSession.selectList("Message.queryMessageList");//空指針異常
??} catch (IOException e) {
???e.printStackTrace();
??} finally {
???if(sqlSession!=null){
????sqlSession.close();
???}
??}
??return list;
??
?}