How can pass a form parameter value to a same jsp file?

K

kaiwing18

Hi,


I have a following jsp file called "showAsset.jsp" :

<form action="showAsset.jsp" method="post">
<tr BGCOLOR=YELLOW>

<td><input name="sort" type="submit" value="Asset_Number" > </td>
<td><input name="sort" type="submit" value="Description"></td>
<td><input name="sort" type="submit" value="Quantity"></td>
<td><input name="sort" type="submit" value="Sub System"></td>
<td><input name="sort" type="submit" value="Model"></td>

</tr>
</form>

<% String sort1=request.getParameter("sort");
String i=" ";
if (sort1.equals("Asset_Number"))
i="Asset_Number";
else if(sort1.equals("Description"))
i="Description";
else
i="Type";
%>

<%=i%>

But when i put it in Tomcat5.0 server, It give me the following error
message:
-------------------------------------------------------------------------------
HTTP Status 500 -



type Exception report

message

description The server encountered an internal error () that prevented
it from fulfilling this request.

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:358)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)


root cause

java.lang.NullPointerException
org.apache.jsp.testdb.showAsset1_jsp._jspService(showAsset1_jsp.java:61)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:311)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
-------------------------------------------------------------------------------

My question is that how can i pass a form value to a same jsp file



Thank you

Ricky
 
S

Sudsy

java.lang.NullPointerException
org.apache.jsp.testdb.showAsset1_jsp._jspService(showAsset1_jsp.java:61)

So what's happening on line 61 of showAsset1.jsp? Kind of hard to
offer a solution without all the pieces of the puzzle...
 
J

Jesper Mortensen

Hi,


I have a following jsp file called "showAsset.jsp" :

<form action="showAsset.jsp" method="post">
<tr BGCOLOR=YELLOW>

<td><input name="sort" type="submit" value="Asset_Number" > </td>
<td><input name="sort" type="submit" value="Description"></td>
<td><input name="sort" type="submit" value="Quantity"></td>
<td><input name="sort" type="submit" value="Sub System"></td>
<td><input name="sort" type="submit" value="Model"></td>

</tr>
</form>

<% String sort1=request.getParameter("sort");

The first time the page loads, the 'sort' parameter does not exist, so the
request.getParameter("sort") returns null, hereby the NullPointerException.

You could do something like this :

String i = null;
if ((i = request.getParameter("sort")) == null)
{
i = "Type";
}
else if (!i.equals("Asset_Number") || !i.equals("Description")){
i = "Type";
}

(It could be done in one ternary sentence, but don't, others would proberly
not be able to understand the meaning later on :) )
String i=" ";
if (sort1.equals("Asset_Number"))
i="Asset_Number";
else if(sort1.equals("Description"))
i="Description";
else
i="Type";
%>

<%=i%>

But when i put it in Tomcat5.0 server, It give me the following error
message:
-------------------------------------------------------------------------- -----
HTTP Status 500 -



type Exception report

message

description The server encountered an internal error () that prevented
it from fulfilling this request.

exception

org.apache.jasper.JasperException
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:3
58)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:301)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:248)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)


root cause

java.lang.NullPointerException
org.apache.jsp.testdb.showAsset1_jsp._jspService(showAsset1_jsp.java:61)
org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:133)
javax.servlet.http.HttpServlet.service(HttpServlet.java:856)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:3
11)
-----

My question is that how can i pass a form value to a same jsp file



Thank you

Ricky

Hope it helps !

Best

/Jesper P Mortensen

"According to Kentucky state law, every person must take a bath at least
once a year !"
 
G

GaryM

String i = null;
if ((i = request.getParameter("sort")) == null)
{
i = "Type";
}
else if (!i.equals("Asset_Number") || !i.equals("Description")){
i = "Type";
}

Doesn't 'if("Assest_Number".equals(i) .... etc' remove the need for the
null check?
 

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