请高手帮我看看这条if语句是出什么毛病了?

[honey_001]

代码如下,运行在weblogic8下:
int folderNO=0;
System.out.println(request.getParameter("folderNO"));
if ((request.getParameter("folderNO")!=null)&&(!request.getParameter("folderNO").equals("")))
{
System.out.println("fffffffffffffffffffff");
folderNO=Integer.parseInt(request.getParameter("folderNO"));

}
else if(request.getParameter("folderNO")==null)
{folderNO=0;}

我的folderNO的值为null时,仍执行了
System.out.println("fffffffffffffffffffff");
folderNO=Integer.parseInt(request.getParameter("folderNO"));
部分,请问是哪儿错了?

[catblue]

你跳转的语句是怎么写的？

[titaninwinter]

!request.getParameter("folderNO").equals("null");

[dvictor]

&&改成||
用或

[tom2005]

out.println(request.getParameter("folderNO")!=null);
测一下

[dvictor]

不好意思 看错了

[honey_001]

我改成||还是执行了System.out.println("fffffffffffffffffffff");
folderNO=Integer.parseInt(request.getParameter("folderNO"));
.

[catblue]

request.getParameter("folderNO")；返回的值或者是String 或者是空。
等于null只有一个情况那就是 传递给此方法的参数名没有实际的参数与之对应。

如果你的jsp里有folderNO这个参数 那就不会是null。所以肯定会执行第一个条件。
你把jsp里folderNO参数改一下名试一下，应该就执行第二个条件

[honey_001]

太奇怪了,我用out.println(request.getParameter("folderNO"));
out.println(request.getParameter("folderNO")==null);
测试,竟然答案是null,false,真是奇怪呀.

[honey_001]

to catblue(limiaomiao):
相当于我是从这个页面
<%
String folderNO=request.getParameter("folderNO");
String curPageNo="1";
if(request.getParameter("curPageNo")!=null)
{
curPageNo=request.getParameter("curPageNo");
}
String controlFolderPurView="10";
if(request.getParameter("controlFolderPurView")!=null)
{
controlFolderPurView=request.getParameter("controlFolderPurView");
}
%>
<frameset cols="214,*" frameborder="NO" border="0" framespacing="0" rows="*" onLoad='initializeTree()'>
<frame name="treeFrame" scrolling="no" noresize src="" frameborder="NO">
<frame SRC="/SowantOA?functionId=131004&folderNO=<%=folderNO%>&curPageNo=<%=curPageNo%>&controlFolderPurView=<%=controlFolderPurView%>" name="folderFrame" scrolling="AUTO" frameborder="NO" noresize>
</frameset><noframes></noframes>`
跳转到
int folderNO=0;
System.out.println(request.getParameter("folderNO"));
if ((request.getParameter("folderNO")!=null)&&(!request.getParameter("folderNO").equals("")))
{
System.out.println("fffffffffffffffffffff");
folderNO=Integer.parseInt(request.getParameter("folderNO"));

}
else if(request.getParameter("folderNO")==null)
{folderNO=0;}
该如何修改,才可以使参数传输成功,又不至于错误?

[tom2005]

返回的是字符串""
改这个试试
else if(request.getParameter("folderNO").equals(""))

[HITZXL]

int folderNO=0;
System.out.println(request.getParameter("folderNO"));
if (request.getParameter("folderNO")!=null)
{if(!(request.getParameter("folderNO").equals(""))){
System.out.println("fffffffffffffffffffff");
folderNO=Integer.parseInt(request.getParameter("folderNO"));
}
}
else if(request.getParameter("folderNO")==null)
{folderNO=0;}
应该改成这样