JSP使用JDBC完成动态验证及采用MVC完成数据查询的方法

public boolean check(){/*   if(username==null || userpass==null)     return false;   if(username.equals("zhangsan") && userpass.equals("lisi"))   {     return true;   }else{     return false;   }*/   Connection con = null;   Statement stmt = null;   ResultSet rs = null;   boolean b = true;   try{     // 指出连接数据库所需要的驱动程序     Class.forName("oracle.jdbc.driver.OracleDriver");    // 建立与数据库之间的连接// myserver修改为数据库服务器IP，mydb为数据库名    con = DriverManager.getConnection("jdbc:oracle:thin:@myserver:1521:mydb","scott","tiger");    // 编写查询数据库信息的SQL语句    String sql="select * from usertable where username='"+username+"' and userpass='"+userpass+"'";    System.err.println(sql);    // 创建语句对象，用于执行SQL语句    stmt = con.createStatement();    // 执行SQL语句得到结果集    rs = stmt.executeQuery(sql);       // 判断rs中是否有数据    if(rs.next())     b = true;    else     b = false;   }catch(Exception e){     System.out.println(e.getMessage());   }   finally{    // 关闭相关对象    if(rs!=null) try{ rs.close(); }catch(Exception ee){}    if(stmt!=null) try{ stmt.close(); }catch(Exception ee){}    if(con!=null) try{ con.close(); }catch(Exception ee){}   }   return b;}

public ArrayList getAllUser(){   Connection con = null;   Statement stmt = null;   ResultSet rs = null;   ArrayList users = new ArrayList();   try{    // 指出连接数据库所需要的驱动程序    Class.forName("oracle.jdbc.driver.OracleDriver");    // 建立与数据库之间的连接    con = DriverManager.getConnection("jdbc:oracle:thin:@myserver:1521:mydb","scott","tiger");    // 编写查询数据库信息的SQL语句    String sql="select * from usertable";    // 创建语句对象，用于执行SQL语句    stmt = con.createStatement();    // 执行SQL语句得到结果集    rs = stmt.executeQuery(sql);       // 遍历结果集    while(rs.next())    {      String username = rs.getString(1);      String userpass = rs.getString(2);      // java.util.Date birthday = rs.getDate(3);      // int age = rs.getInt(4);      User user = new User();      user.setUsername(username);      user.setUserpass(userpass);      users.add(user);    }   }catch(Exception e){     System.out.println(e.getMessage());   }   finally{    // 关闭相关对象    if(rs!=null) try{ rs.close(); }catch(Exception ee){}    if(stmt!=null) try{ stmt.close(); }catch(Exception ee){}    if(con!=null) try{ con.close(); }catch(Exception ee){}   }      return users;}

package servlet;import java.io.*;import javax.servlet.*;import javax.servlet.http.*;import javabean.*;import java.util.*;public class GetAllUser extends HttpServlet{  public void doGet(HttpServletRequest request,HttpServletResponse response)  throws IOException,ServletException  {   // 第一步：获取用户的输入信息，这里不需要   // 第二步：调用JavaBean   User user = new User();   ArrayList users=null;   users = user.getAllUser();   // 第三步：传值   request.setAttribute("users",users);   // 第四步：选择一个界面对用户进行响应   String forward="userlist.jsp";   RequestDispatcher rd = request.getRequestDispatcher(forward);   rd.forward(request,response);  }  public void doPost(HttpServletRequest request,HttpServletResponse response)  throws IOException,ServletException  {   doGet(request,response);  }}

  <servlet>   <servlet-name>getAllUser</servlet-name>   <servlet-class>servlet.GetAllUser</servlet-class>  </servlet>  <servlet-mapping>   <servlet-name>getAllUser</servlet-name>   <url-pattern>/getAllUser</url-pattern>  </servlet-mapping>

<%@ page contentType="text/html;charset=gb2312"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><c:forEach var="user" items="${users}">  用户名：${user.username} 口令：${user.userpass} <br></c:forEach>