Java JSP getParameter显示空字

Question

I have a "Hello World JSP" i need to get the users name from the URL and display it, It works fine but it needs to display a generic "World" if not user name is there. 我有一个“ Hello World JSP”，我需要从URL中获取用户名并显示它，它可以正常工作，但是如果没有用户名，则需要显示一个通用的“ World”。

Im not sure how to accomplish that? 我不确定如何做到这一点？ were do i put "world" in my code to make it display if no user name is present? 如果没有用户名，我应该在代码中放入“世界”以使其显示吗？

Thanks! 谢谢！

 <HTML>
<BODY>
Hello <b><%= request.getParameter("user") %>World</b>!
</Body>
</HTML>

Answer 1

You can avoid the scriptlet by using JSP EL's ternary operator: 您可以通过使用JSP EL的三元运算符来避免scriptlet：

<HTML>
<BODY>
Hello <b>${not empty requestScope.user ?  requestScope.user: 'World'}</b>!
</Body>
</HTML>

Answer 2

Because you want to do this in an old fashioned way , do as below: 因为您想以老式的方式进行操作 ，所以请执行以下操作：

<%

String user = "", wordDisplay = "";

user = request.getParameter("user");

if(user != null && !user.equals(""))    
wordDisplay = user;     
else    
wordDisplay = "World";

%>

<HTML>
<BODY>
Hello <b><%= wordDisplay %></b>!
</Body>
</HTML>

Answer 3

I suggest you to do not use style of coding. 我建议您不要使用编码样式。 But still if you are interested ,then 但是如果你有兴趣的话

Try this :- 尝试这个：-

<%
String vuser=request.getParameter("user");
if(vuser==null || vuser.equals("")){
   vuser="World";
}

%>

JSP Code :- JSP代码：-

<HTML>
   <BODY>
       Hello <%=vuser%> 
   </Body>
</HTML>

Hope it will help you. 希望对您有帮助。

Java JSP getParameter显示空字

问题描述

3 个解决方案

解决方案1
1 2013-05-24 00:31:26

解决方案2
0 已采纳 2013-05-24 01:31:27

解决方案3
0 2013-05-24 02:31:32

Java JSP getParameter显示空字

问题描述

3 个解决方案

解决方案1 1 2013-05-24 00:31:26

解决方案2 0 已采纳 2013-05-24 01:31:27

解决方案3 0 2013-05-24 02:31:32

解决方案1
1 2013-05-24 00:31:26

解决方案2
0 已采纳 2013-05-24 01:31:27

解决方案3
0 2013-05-24 02:31:32