package con.edu.bean;
    public class Add{
        private int a;
        private int b;
        public Add(int a, int b){this.a=a; yhis.b=b; }
        public Add(){}
        public int sum(){
          int c, s=0;
          if(a＞b){c=a; a=b; b=c; }
          for(int x=a; x＜=b; ++x){ s += x; }
          return s;
        }
      //省略了各屬性的setter/getter方法
    }

    ＜body＞ ＜%
          Integer d1=(Integer)request.getAttribute("out1");
          Integer d2=(Integer)request.getAttribute("out2");
          Integer sum=(Integer)request.getAttribute("out_sum"); %＞
          ＜p＞＜%=d1%＞加到＜%= d2%＞的和值是： ＜%= sum%＞ ＜/p＞
    ＜/body＞

    package edu.com.model;
    public class Student {
      private int id;
      private String username;
      private String userpassword;
      //省略了各屬性的getter/setter方法
    }

    package com.db;
    import java.sql.*;
    public class DbConnect {
      private static String driverName="com.mysql.jdbc.Driver";  //驅(qū)動(dòng)程序名
      private static String userName="root";                //數(shù)據(jù)庫(kù)用戶名
      private static String userPwd="123456";               //密碼
      private static String dbName="user";                  //數(shù)據(jù)庫(kù)名
      public static Connection getDBconnection(){
        String  url1="jdbc:mysql://localhost/"+dbName;
        String  url2="? user="+userName+"&password="+userPwd;
        String  url3="&useUnicode=true&characterEncoding=UTF-8";
        String  url=url1+url2+url3;
        Connection con=null;
        try{
            Class.forName(driverName);
            con=DriverManager.getConnection(url);
          }catch (Exception e) {e.printStackTrace(); }
        return con;
        }
        public static void closeDB(Connection con, PreparedStatement pstm, ResultSet rs){
        try{
          if(rs! =null) rs.close();
          if(pstm! =null) pstm.close();
          if(con! =null) con.close();
        }catch (SQLException e) {e.printStackTrace(); }
      }
    }

    package edu.com.dao;
    //省略了import;
    public class UserDAO{
        //實(shí)現(xiàn)向數(shù)據(jù)庫(kù)中添加記錄的方法
      public int insert(User user) throws Exception{
        Connection con=null;
        PreparedStatement prepStmt=null;
        ResultSet rs=null;
        con=DbConnect.getDBconnection();
        String sql="insert into user_b(username, userpassword) values (? , ? )";
        prepStmt =con.prepareStatement(sql);
        prepStmt.setString(1, user.getUsername());
        prepStmt.setString(2, user.getUserpassword());
        int n=prepStmt.executeUpdate();
        close(prepStmt); close(con);
        return n;
      }
    //實(shí)現(xiàn)查詢數(shù)據(jù)庫(kù)中對(duì)指定的記錄是否存在的方法
      public User find(User user) throws Exception {
          Connection con=null;
          PreparedStatement prepStmt=null;
          ResultSet rs=null;
          User user2 = null;
          con=getDBconnection();
          String sql="select * from user_b where username=? and userpassword=? ";
          prepStmt = con.prepareStatement(sql);
          prepStmt.setInt(1, user.getUsername());
          prepStmt.setInt(2, user.getUserpassword());
          rs = prepStmt.executeQuery();
          if (rs.next()){
              user2 = new User();
              user2.setId(rs.getInt("id"));
              stu2.setUsername(rs.getString("username"));
              stu.setUserpassword(rs.getString("userpassword"));
          }
          close(rs); close(prepStmt); close(con);
          return user2;
      }
      //實(shí)現(xiàn)列出數(shù)據(jù)庫(kù)全部記錄的方法
      public List＜Student＞ findAll() throws Exception {//給出實(shí)現(xiàn)方法}
      //實(shí)現(xiàn)刪除數(shù)據(jù)庫(kù)中指定的記錄的方法
      public void remove(Student stu)throws Exception{//給出實(shí)現(xiàn)方法 }
      //實(shí)現(xiàn)用指定的對(duì)象修改數(shù)據(jù)庫(kù)中記錄的方法
      public void update(Student stu) throws Exception {//給出實(shí)現(xiàn)方法}
    }

    ＜body＞
        ＜form  action="userChecked"method="post"＞
            用 戶 名：＜input type="text"name="xm"＞＜br＞＜br＞
            用戶密碼：＜input type="password" name="mm"＞＜br＞＜br＞
            ＜input type="submit" value="登錄"＞
        ＜/form＞
    ＜/body＞

    ＜html＞
      ＜head＞ ＜title＞登錄驗(yàn)證成功頁(yè)面＜/title＞ ＜/head＞
      ＜body＞＜%=request.getParameter("xm")%＞：登錄成功?。糱r＞  ＜/body＞
    ＜/html＞

    ＜html＞
      ＜head＞ ＜title＞登錄驗(yàn)證出錯(cuò)頁(yè)面＜/title＞ ＜/head＞
      ＜body＞ ＜%=request.getParameter("xm") %＞：登錄失?。。糱r＞ ＜/body＞
    ＜/html＞