<%@ page language="java" import="java.sql.*" pageEncoding="GB18030"%>
<%request.setCharacterEncoding("gb2312");%>
<html>
<head>
</head>
<body bgColor=#4e7dd1>
<form action="webedit.jsp" method="post">
<table align="center">
<tr><td align="center"><FONT style="FONT-SIZE: 15pt" color=#eff5fa>后台网络收藏夹管理</FONT></td></tr>
<jsp:useBean id="resource" scope="page" class="sju.sjumis.yuanding.util.TeacherDBBean"></jsp:useBean>
<%String address = request.getParameter("webaddress");
String name = "benwei";
ResultSet rs = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rs.next())
{%>
<tr><td>网站名称:</td><td><input type="text" name="text1" value=<%=rs.getString("webname")%>></td></tr>
<tr><td>网站地址:</td><td><input type="text" name="text2" value=<%=rs.getString("hrefaddress")%>></td></tr>
<tr><td>网站名称:</td><td><input type="text" name="text3" value=<%=rs.getString("re")%>></td></tr>
<tr><td><input type="hidden" name="text4" value=<%=rs.getString("hrefaddress")%>></td></tr>
<%}
else
{%>
<tr><td>网站名称:</td><td><input type="text" name="text1"></td></tr>
<tr><td>网站地址:</td><td><input type="text" name="text2"></td></tr>
<tr><td>网站名称:</td><td><input type="text" name="text3"></td></tr>
<%}resource.closeStmt();%>
<tr>
<td align="center"><input name="" type="submit" value="提交" /></td>
<td align="center"><input name="" type="reset" value="重置" /></td>
</tr>
</table>
<%
String text1Value = request.getParameter("text1");
String text2Value = request.getParameter("text2");
String text3Value = request.getParameter("text3");
String text4Value = request.getParameter("text4");
if(text1Value == null && text1Value == null && text1Value == null)
{
ResultSet rw = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rw.next())
{
if(rw.getString("webname").equals(text1Value) && rw.getString("hrefaddress").equals(text1Value) && rw.getString("re").equals(text1Value))
out.print("<script>alert('请修改信息后再提交...');</script>");
else
{
//out.print(text1Value+"<br>");out.print(text2Value+"<br>");out.print(text3Value+"<br>");out.print(text4Value+"<br>");
resource.executeUpdate("update collectioncontent set webname='"+text1Value+"',hrefaddress='"+text2Value+"',re='"+text3Value+"' where hrefaddress='"+ text4Value + "' and username='" +name+"'");
out.print("<script>alert('信息也成功修改...');</script>");
out.print("<script>window.close();</script>");
}
}
}
</form>
</body>
</html>为什么第二个ResultSet rw执行不了...
因没有rs.next()是false
所以"if(rw.next()){...."下面都不执行了?
<%request.setCharacterEncoding("gb2312");%>
<html>
<head>
</head>
<body bgColor=#4e7dd1>
<form action="webedit.jsp" method="post">
<table align="center">
<tr><td align="center"><FONT style="FONT-SIZE: 15pt" color=#eff5fa>后台网络收藏夹管理</FONT></td></tr>
<jsp:useBean id="resource" scope="page" class="sju.sjumis.yuanding.util.TeacherDBBean"></jsp:useBean>
<%String address = request.getParameter("webaddress");
String name = "benwei";
ResultSet rs = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rs.next())
{%>
<tr><td>网站名称:</td><td><input type="text" name="text1" value=<%=rs.getString("webname")%>></td></tr>
<tr><td>网站地址:</td><td><input type="text" name="text2" value=<%=rs.getString("hrefaddress")%>></td></tr>
<tr><td>网站名称:</td><td><input type="text" name="text3" value=<%=rs.getString("re")%>></td></tr>
<tr><td><input type="hidden" name="text4" value=<%=rs.getString("hrefaddress")%>></td></tr>
<%}
else
{%>
<tr><td>网站名称:</td><td><input type="text" name="text1"></td></tr>
<tr><td>网站地址:</td><td><input type="text" name="text2"></td></tr>
<tr><td>网站名称:</td><td><input type="text" name="text3"></td></tr>
<%}resource.closeStmt();%>
<tr>
<td align="center"><input name="" type="submit" value="提交" /></td>
<td align="center"><input name="" type="reset" value="重置" /></td>
</tr>
</table>
<%
String text1Value = request.getParameter("text1");
String text2Value = request.getParameter("text2");
String text3Value = request.getParameter("text3");
String text4Value = request.getParameter("text4");
if(text1Value == null && text1Value == null && text1Value == null)
{
ResultSet rw = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rw.next())
{
if(rw.getString("webname").equals(text1Value) && rw.getString("hrefaddress").equals(text1Value) && rw.getString("re").equals(text1Value))
out.print("<script>alert('请修改信息后再提交...');</script>");
else
{
//out.print(text1Value+"<br>");out.print(text2Value+"<br>");out.print(text3Value+"<br>");out.print(text4Value+"<br>");
resource.executeUpdate("update collectioncontent set webname='"+text1Value+"',hrefaddress='"+text2Value+"',re='"+text3Value+"' where hrefaddress='"+ text4Value + "' and username='" +name+"'");
out.print("<script>alert('信息也成功修改...');</script>");
out.print("<script>window.close();</script>");
}
}
}
</form>
</body>
</html>为什么第二个ResultSet rw执行不了...
因没有rs.next()是false
所以"if(rw.next()){...."下面都不执行了?
就为:
if(text1Value != null && text1Value != null && text1Value != null)
ResultSet rw = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rw.next())
---------------------------------
关闭了,还用来执行?
ResultSet rw = resource.executeQuery("select * from collectioncontent where hrefaddress='"+address+"' and username='" +name+"'");
if(rw.next())
---------------------------------
关闭了,还用来执行?
又发现一个问题:从数据库取出来的字符串能不能和字符变量比较?即:
rw.getString("webname").equals(text1Value)
rw.getString("webname")取出来的值为空就不能比较了,会抛空指针异常。
text1Value是一次取出来的.
再取一次比较为什么就不行了呢?