为什么会提示ArrayList错误呢？

Question

代码如下public ArrayList<UserBean> getUsersByPage(int pageNow){try{ArrayList<UserBean> al=new ArrayList<UserBean>();ct=new ConnDB().getConn();rs=sm.executeQuery("select top "+pageSize+" * from users where userId not in(select top "+pageSize*(pageNow-1)+" userId from users) " );while(rs.next()){UserBean ub=new UserBean();ub.setUserId(rs.getInt(1));ub.setUserName(rs.getString(2));ub.setPasswd(rs.getString(3));ub.setEmail(rs.getString(4));ub.setGrade(rs.getInt(5));al.add(ub);}}catch(Exception e){e.printStackTrace();}finally{this.close(); }return al;}

Answer 1

public List<UserBean> getUsersByPage(int pageNow)
{
List<UserBean> al=new ArrayList<UserBean>();
try
{
ct=new ConnDB().getConn();

rs=sm.executeQuery("select top "+pageSize+" * from users where userId not in(select top "+pageSize*(pageNow-1)+" userId from users) " );
while(rs.next())
{
UserBean ub=new UserBean();
ub.setUserId(rs.getInt(1));
ub.setUserName(rs.getString(2));
ub.setPasswd(rs.getString(3));
ub.setEmail(rs.getString(4));
ub.setGrade(rs.getInt(5));

al.add(ub);
}
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
this.close(); 
}
return al;
}

Answer 2

ArrayList<UserBean> al=new ArrayList<UserBean>();

改成 如下

List<UserBean> al = new ArrayList<UserBean>();