JSP/Servlet 数据库分页 原理 解析 下载

package org.zzz.page.dao; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import org.zzz.page.common.PageModel; import org.zzz.page.dto.User; public class UserListDao { public List<User> getUserByPage(PageModel pageModel) { Connection conn = null; List<User> userlist = new ArrayList<>(); try{ Class.forName("com.mysql.jdbc.Driver"); conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/page", "root", "root"); PreparedStatement pstmt = conn.prepareStatement("select count(*) from tb_user"); ResultSet rs = pstmt.executeQuery(); int resultCount = 0; while(rs.next()){ resultCount = rs.getInt(1); } if(resultCount ==0){ return userlist; } pageModel.setResultCount(resultCount); String sql = "SELECT * FROM tb_user limit ?,?"; pstmt = conn.prepareStatement(sql); pstmt.setInt(1,pageModel.getStartPosition()); pstmt.setInt(2,PageModel.getResultlimit()); rs = pstmt.executeQuery(); while (rs.next()){ User user = new User(); user.setId(rs.getInt(1)); user.setUsername(rs.getString(2)); user.setPassword(rs.getString(3)); userlist.add(user); } return userlist; }catch(Exception e){ e.printStackTrace(); }finally{ try{ if (conn != null) conn.close(); }catch(Exception ex){ ex.printStackTrace(); } } return null; } }