jsp实现的网络通讯录

package com.operation; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; import java.util.*; import com.common.DBConnection; import com.entity.User; /* * 用户对数据库操作方法管理类 */ public class UserBo { private Connection conn;// 保存数据库连接对象 private Statement stmt;// 用于执行SQL语句 private PreparedStatement psts;// 执行SQL语句（预处理） private ResultSet rs;// 保存查询的结果集 /** * 判断当前输入用户名和密码是否正确并封装user对象 * * @param username * @param password * @return 用户对象 user */ public User validUser(String username, String password) { User user = null; String sql = "select * from user where username= ? and password= ?;"; try { conn = DBConnection.getConnection(); psts = conn.prepareStatement(sql); psts.setString(1, username); psts.setString(2, password); rs = psts.executeQuery(); if (rs.next()) { user = new User(); user.setUserid(rs.getInt("userid")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); user.setRealname(rs.getString("realname")); user.setSex(rs.getString("sex")); } } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeResultSet(rs); DBConnection.closeStatement(psts); DBConnection.closeConnection(); } return user; } /** * 通过预处理语句进行用户的添加 * * @param user * @return count影响行数 */ public int insertUser(User user) { String sql = "insert into user(username,password,realname,sex) values(?,?,?,?) "; int count = 0; try { conn = DBConnection.getConnection(); psts = conn.prepareStatement(sql); psts.setString(1, user.getUsername()); psts.setString(2, user.getPassword()); psts.setString(3, user.getRealname()); psts.setString(4, user.getSex()); count = psts.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeStatement(psts); DBConnection.closeConnection(); } return count; } /** * 根据传入的页面数和页面大小对页面进行分页并将user对象添加到链表中 * * @param pagesize * @param pagecount * @return list链表 */ public List selectAllUser(int pagesize, int pagecount) { List list = new ArrayList(); String sql = "select * from user limit " + (pagesize - 1) * pagecount + "," + pagecount; // System.out.println(sql); try { conn = DBConnection.getConnection(); stmt = conn.createStatement(); rs = stmt.executeQuery(sql); while (rs.next()) { User user = new User(); user.setUserid(rs.getInt("userid")); user.setUsername(rs.getString("username")); user.setPassword(rs.getString("password")); user.setRealname(rs.getString("realname")); user.setSex(rs.getString("sex")); list.add(user); } } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeResultSet(rs); DBConnection.closeStatement(stmt); DBConnection.closeConnection(); } return list; } /** * 根据通讯录userid删除相关信息 * * @param userid * @return 影响数据库行数 */ public int deleteUserByUserid(String userid) { String sql = "delete from user where userid= ? "; int count = 0; try { conn = DBConnection.getConnection(); psts = conn.prepareStatement(sql); psts.setString(1, userid); // System.out.println(sql); count = psts.executeUpdate(); } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeStatement(psts); DBConnection.closeConnection(); } return count; } /** * 根据用户名对密码进行更新 * @param username * @param password1 * @return */ public int UpdateUserByUserid(String username, String password1) { String sql = "update user set password='" + password1 + "' where username = '" + username + "';"; int count = 0; try { conn = DBConnection.getConnection(); stmt = conn.createStatement(); count = stmt.executeUpdate(sql); } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeStatement(stmt); DBConnection.closeConnection(); } return count; } /** * 通过对数据库查询页数 * @return 页面总页数 */ public int getAllnum() { int totalPages = 0; String sql = "select count(*) from user"; conn = DBConnection.getConnection(); try { stmt = conn.createStatement(); rs = stmt.executeQuery(sql); rs.next(); totalPages = rs.getInt(1); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return totalPages; } /** * 通过查询用户名来判断用户是否存在 * @param username * @return */ public boolean voidUser(String username) { boolean flag = false; String sql = "select * from user where username='" + username + "'"; try { conn = DBConnection.getConnection(); stmt = conn.createStatement(); rs = stmt.executeQuery(sql); if (rs.next()) { flag = true; } else { flag = false; } } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeResultSet(rs); DBConnection.closeStatement(stmt); DBConnection.closeConnection(); } return flag; } /** * 通过用户名和密码来更新用户的密码 * @param username * @param password * @return */ public boolean voidUser(String username, String password) { //System.out.println("sss" + username + "我进来了" + password); boolean flag = false; String sql = "select * from user where username='" + username + "'and password='" + password + "';"; try { conn = DBConnection.getConnection(); stmt = conn.createStatement(); rs = stmt.executeQuery(sql); if (rs.next()) { flag = true; } else { flag = false; } } catch (Exception e) { e.printStackTrace(); } finally { DBConnection.closeResultSet(rs); DBConnection.closeStatement(stmt); DBConnection.closeConnection(); } return flag; } }