分页显示

//从数据库中取出数据
        //到数据库中去验证
                Connection conn = null;
                PreparedStatement ps = null;
                ResultSet rs = null;
                //分页定义变量
                
                int pageNow=1;//当前页
                //接受用户的pageNow
                String spageNow=request.getParameter("pageNow");
                if(spageNow!=null){
                    pageNow=Integer.parseInt(spageNow);
                }
                int pageSize=3;//指定显示3条记录
                int pageCount=1;//该值是计算出来的
                int rowCount=1;//该共有多少记录，数据库计算出来的
                try{
                    //1加载驱动
                    
                    Class.forName("com.mysql.jdbc.Driver");
                    //2.得到连接
                    
                    conn = DriverManager.getConnection(
                            "jdbc:mysql://localhost:3306/user", "root", "123456");
                   
                     
                    //算出共有多少页
                //1.查询rowcount
                    String sql1 ="select count(*)  from user";
                    ps = conn.prepareStatement(sql1);
                    rs=ps.executeQuery();
                    rs.next();
                    rowCount=rs.getInt(1);
                    pageCount=rowCount%pageSize==0?rowCount/pageSize:rowCount/pageSize+1;
                    
                    
                    //3.创建PrepareSatement
                    //请大家思考，如果条件是pageNow=2，pageSize=3
                    String sql = "select t.*  from (select * from user order by id) t  limit "+(pageNow-1)*pageSize+","+pageSize+"";
                   //执行操作
                    ps = conn.prepareStatement(sql);
                    rs=ps.executeQuery();
                    out.println("<table border=1px bordercolor=green 0 width=500px>");
                    out.println("<tr><th>ID</th><th>用户名</th><th>密码</th></tr>");
                    while(rs.next()){
                        out.println("<tr><td>"+rs.getInt(1)+
                                "</td><td>"+rs.getString(2)+
                                "</td><td>"+rs.getString(3)+
                                "</td></tr>");
                    }
                    out.println("</table>");
                    //显示上一页
                    if(pageNow!=1){
                    out.println("<a href=‘/LoginServlet/ManageUsers?pageNow="+(pageNow-1)+"‘>上一页</a>");
                    }
                    //显示分页
                    for(int i=1;i<=pageCount;i++){
                        out.println("<a href=‘/LoginServlet/ManageUsers?pageNow="+i+"‘><"+i+"></a>");
                    }
                    //显示上一页
                    if(pageNow!=pageCount){
                    out.println("<a href=‘/LoginServlet/ManageUsers?pageNow="+(pageNow+1)+"‘>下一页</a>");
                    }
                    
                    //显示分页信息
                    out.println("&nbsp;&nbsp;&nbsp;当前页"+pageNow+"/总页数"+pageCount+"<br>");
                    out.println("跳转到<input type=‘text‘ id=‘pageNow‘ name=‘pageNow‘><input type=‘button‘ onClick=‘gotoPageNow()‘ value=‘跳‘/>");
                    
                    
                    }catch(Exception e){
            
        }finally{
            if (ps != null) {
                try {
                    ps.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }
            if (conn != null) {
                try {
                    conn.close();
                } catch (SQLException e) {
                    e.printStackTrace();
                }
            }