为什么加上这一句就出现异常？请高手看看！

[村北头的码农]

<%
String name = sqlbean.toByteString(request.getParameter("name"));
String password = sqlbean.toByteString(request.getParameter("password"));
String username = sqlbean.toByteString(request.getParameter("username"));
String question = sqlbean.toByteString(request.getParameter("question"));
String answer = sqlbean.toByteString(request.getParameter("answer"));
String email = sqlbean.toByteString(request.getParameter("email"));
String mobile = sqlbean.toByteString(request.getParameter("mobile"));
String tel = sqlbean.toByteString(request.getParameter("tel"));
String depart = sqlbean.toByteString(request.getParameter("company"));
String ip = request.getRemoteAddr();
String pagesize = request.getParameter("pagesize");
String sex =sqlbean.toByteString(request.getParameter("sex"));
String Address =sqlbean.toByteString(request.getParameter("Address"));
String marriage =sqlbean.toByteString(request.getParameter("marriage"));

String sql = "select * from Usr where username='"+ username +"' or name='"+ name +"'";
sqlbean.executeQuery(sql);
if(sqlbean.next())//为什么加上这一句后就出现异常
{
out.println(。。。。。);//内容省略
}
else
{
}
去掉if(sqlbean.next())后，就正常输出，错误如下：
java.lang.NullPointerException
我测试了几次，发现错误就在if(sqlbean.next())这一句，
请高手指点，这一句改咋写？

[trumplet]

sqlbean是啥类型的？从代码看，应该是Statement。

Statement有next()方法吗？

[Net8Java]

rs=sqlbean.executeQuery(sql);
if(rs.next()){
out.println(.......);
}
else{
}

[wangwei8117]

sqlbean.executeQuery(sql)是有返回值的啊！应该ResultSet rs=sqlbean.executeQuery(sql);
rs.next();
sqlbean不是记录集，怎么会有next()方法呢！

[aspgreener]

回复人： trumplet(检查) ( ) 信誉：99 2004-11-03 21:59:00 得分: 0


sqlbean是啥类型的？从代码看，应该是Statement。

Statement有next()方法吗？


Top

回复人： Net8Java(杜杜) ( ) 信誉：100 2004-11-04 02:46:00 得分: 0


rs=sqlbean.executeQuery(sql);
if(rs.next()){
out.println(.......);
}
else{
}





Top

回复人： wangwei8117(Jack_David) ( ) 信誉：100 2004-11-04 08:26:00 得分: 0


sqlbean.executeQuery(sql)是有返回值的啊！应该ResultSet rs=sqlbean.executeQuery(sql);
rs.next();
sqlbean不是记录集，怎么会有next()方法呢！

[aoleiaolei]

ResultSet rs = sqlbean.executeQuery(sql.toString());
if (rs.next()){
}
必须生成ResultSet du对象

[wandou999]

只有ResultSet才可以这样写,
ResultSet rs=sqlbean.executeQuery(sql);
while(rs.next())
{...}