不能第二次访问数据库
<%@ 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( "remark ")%> > </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( "remark ").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+ " ',remark= ' "+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?
[解决办法]
<%}resource.closeStmt();%>
ResultSet rw = resource.executeQuery( "select * from collectioncontent where hrefaddress= ' "+address+ " ' and username= ' " +name+ " ' ");
if(rw.next())
---------------------------------
关闭了，还用来执行？
[解决办法]
<%}resource.closeStmt();%>
ResultSet rw = resource.executeQuery( "select * from collectioncontent where hrefaddress= ' "+address+ " ' and username= ' " +name+ " ' ");
if(rw.next())
---------------------------------
关闭了，还用来执行？
[解决办法]
while(rw.next()){}循环结束后，rw的游标定位在结果集的最后了，第二次再读自然就没有数据了。可以在第二次读rw前把rw重定位到开始的位置就好。