package javabean;
public class User
{
  private String username;
  private String userpass;
  public String getUsername()
  {
   return username;
  }
  public void setUsername(String username)
  {
   this.username = username;
  }
  public String getUserpass()
  {
   return userpass;
  }
  public void setUserpass(String userpass)
  {
   this.userpass = userpass;
  }
  public boolean check()
  {
   if(username==null || userpass==null)
     return false;
   if(username.equals("zhangsan") && userpass.equals("lisi"))
   {
     return true;
   }else{
     return false;
   }
  }
}

import javabean;
…
  User user = new User(); // 定义对象，并且实例化
  user.setUsername("zaaaa"); // 对成员变量进行初始化
  user.setUserpass("sssss");  // 对用户口令进行初始化
  boolean b = user.check();  // 调用业务方法进行验证

<%@ page contentType="text/html;charset=gb2312"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

${pageScope.pageAttribute}
${requestScope.requestAttribute}
${sessionScope.sessionAttribute}
${applicationScope.applicationAttribute}

<%@ page contentType="text/html;charset=gb2312"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>

${pageScope.pageAttribute}
${requestScope.requestAttribute}
${sessionScope.sessionAttribute}
${applicationScope.applicationAttribute}

String username = request.getParameter("username");
user.setUsername(username);

String username = request.getParameter("username");
user.setUsername(username);
String userpass = request.getParameter("usernpass");
user.setUsernpass (userpass);

<%
  boolean b = user.check();
%>