JSF启动数据库报错

[Bone2]

高手帮我分析下 我的一个受管bean类实现了对数据库查询操作，但是登陆系统的时候tomcat报错
exception

javax.servlet.ServletException
javax.faces.webapp.FacesServlet.service(FacesServlet.java:256)

root cause

java.lang.NullPointerException
org.jia.EManage.web.SelectExperimentBean.getAdminExperiment(SelectExperimentBean.java:85)

其中报错的85行代码为

public ArrayList<Experiment> getAdminExperiment()throws Exception
	  {
		  return experimentDaoImpl.getAdminExperiment();
	  }

其中具体的数据库操作方法代码为

	public ArrayList<Experiment> getAdminExperiment() throws Exception{
		ArrayList<Experiment> result=new ArrayList<Experiment>();	
		Connection conn=null;
		PreparedStatement stmt=null;
		ResultSet rs=null;
		try{
			conn=DBConn.getCon();
			String sql="select * from experiment where status = ?";
			stmt=conn.prepareStatement(sql);
			stmt.setInt(1, 0);

			while(rs.next()){
				//查询结果转化为Experiment对象
				Experiment experiment=new Experiment();

				experiment.setId(rs.getInt("id"));
				experiment.setAim(rs.getString("aim"));
				experiment.setDescribe(rs.getString("describes"));
				experiment.setComments(rs.getString("comments"));
				experiment.setName(rs.getString("name"));
				experiment.setStatus(rs.getInt("status"));
				experiment.setInitiatedId(rs.getInt("initiatedId"));
			
				result.add(experiment);
			}	
			//取得初始状态的实验列表
				
		}catch(SQLException sqle){
				throw new SQLException("select data exception:"+
						sqle.getMessage());
			}catch(Exception e){

			}
			return result;
			
	}

[Bone2]

晕 居然犯了这样的错误 但是改过之后还是老问题 怎么回事呀！

[hornbilltofy]

rs是在什么地方付值的?
应该有rs=stmt.executeQuery(sql);