首先我是想实现修改的功能，后来显示出Value '0000-00-00' can not be represented as java.sql.Date这样一个问题，按照网上教的方法在连接数据库语句后面添加zeroDateTimeBehavior=convertToNull，结果所有date类型的值都为0000-00-00了，怎么办呢?其实不是很明白网上这个方法的用意，求指教！下面是修改页面和显示页面的代码：
update_cooperation.jsp：
<%@ page contentType="text/html; charset=gb2312" language="java" import="java.sql.*" errorPage="" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>无标题文档</title>
</head>
<body>
<%
Class.forName("com.mysql.jdbc.Driver").newInstance();
String url= "jdbc:mysql://localhost:3306/graduationproject?user=root&password=123&useUnicode=true&characterEncoding=GB2312&zeroDateTimeBehavior=convertToNull";
Connection connection=DriverManager.getConnection(url);
Statement statement = connection.createStatement();
String number=request.getParameter("number");
String sql="select * from cooperations where number='"+number+"'";
ResultSet rs = statement.executeQuery(sql);
%>
<table width="1572">
<tr>
<th width="169" scope="col"> 起始时间</th>
<th width="169" scope="col">结束时间</th>
<th width="166" scope="col">物料</th>
<th width="168" scope="col">项目编号</th>
<th width="169" scope="col"> 项目名称</th>
<th width="167" scope="col">ICP</th>
<th width="168" scope="col"> 供应商名称</th>
<th width="169" scope="col">合作价格</th>
<th width="169" scope="col">状态</th>
</tr>
</table>
<% while(rs.next()) {%>
<form id="form1" name="form1" method="post" action="deal_update_cooperation.jsp">
<table width="1698">
<tr>
<th width="168" height="49" scope="col">
<div align="center">
<input type="hidden" name="number" value="<%=request.getParameter("number")%>"/>
<input type="text" name="begintime" value="<%=rs.getTime("begintime")%>" />
</a></div></th>
<th width="168" scope="col">
<div align="center">
<input type="text" name="endtime" value="<%=rs.getTime("endtime")%>" />
</div></th>
<th width="168" scope="col">
<div align="center">
<input type="text" name="material" value="<%=rs.getString("material")%>" />
</div></th>
<th width="168" scope="col"><div align="center">
<input name="p_number" type="text" value="<%=rs.getString("p_number")%>" />
</div></th>
<th width="168" scope="col">