jsp中调用bean不能执行的问题。在线等！！！

jsp中调用bean不能执行的问题。在线等！！！adminlogin.java:package com;
//import db;
public class adminlogin{
private String Password;
private String Username;
private db db = new db();public String getUsername() {
return Username;
}public void setUsername(String newUsername) {
Username = db.toChinese(newUsername);
}public String getPassword() {
return Password;
}public void setPassword(String newPassword) {
Password = newPassword;
}public boolean CheckAdmin() {
boolean Checktig = false;
try {System.out.print(Username);
String sSql = "select * from admin where username='" + Username + "' and password='"+Password+"'";
if ((db.executeQuery(sSql)).next()) {
Checktig = false;
} else {
Checktig = true;
}
} catch (Exception ex) {
System.err.println("Admin.CheckAdmin: " + ex.getMessage());
} finally {}
return Checktig;
}}有个form:<form name="form1" method="post" action="loginin.jsp">
<div align="center">用户： 
<input name="Username" type="text" id="Username" size="12">
<br>
<br>
密码： 
<input name="Password" type="password" id="Password" size="12">
<br>
<br>
<input type="submit" name="Submit" value="确定">
<input type="reset" name="Submit2" value="重写">
</div>
</form>loginin.jsp:<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<jsp:useBean id="adminlogin" class="com.adminlogin" scope="page"/> 
<jsp:setProperty name="adminlogin" property="*"/> 
<html>
<head>
<title>loginin</title>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
</head><body><% 
String Username = request.getParameter("Username");
out.println("username="+Username);
out.println(adminlogin.getUsername());
if(adminlogin.CheckAdmin()){ 
out.print(adminlogin.getUsername());
//session.setAttribute("login","1");
//response.sendRedirect("manage.jsp");
}else{%> <%
out.println("帐号或者密码不正确！");
out.println(adminlogin.getUsername());
out.println(adminlogin.getPassword());
return;
}%> 
</body>
</html>
输入与数据库中有关和无关的信息，全部不能登陆，比如输入1，输出信息为：username=1 null null 请问我的错误在那里，在线等呀！！！！！！！！