◆如果文本框中是空的,那么request.getParameter得到的什么值?◆
A.jsp内容:
...
<form action="B.jsp" type="post">
<input type="text" name="code">
<input type="submit" name="submit" value=" OK ">
</form>
....
B.jsp内容:
...
<%
String strCode = request.getParameter("code");
if (strCode==""){
out.println("it is empty string");
}else if(strPcode == null){
out.println("it is null");
}
else {
out.println("it is nothing");
}
%>
...
code文本框里不输入内容,直接按"OK"submit,得到的结果是:
"it is nothing"
也就是说,既不是空字符串,也不是null,那么,它究竟是什么值呢?