public ArrayList<Serch> list() throws SQLException
{
    ArrayList<Serch> L=new  ArrayList();
      ResultSet rs=null; 
      String  sql="select * from book";
      DB sqle=new DB();
      rs= sqle.db(sql);
     
      while(rs.next())
      {
           Serch s=new Serch();
           s.setBid(rs.getString(1));
           s.setBname(rs.getString(2));
            s.setNumber(rs.getInt(5)-rs.getInt(6));
            L.add(s);
           int a= L.size();
           
         System.out.println(a);
         
      }
      System.out.println("测试链表长度："+L.size());
      return L;
}

}

JSP显示：
用<s:iterator >标签，
经测试没问题....