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String compare with Form field

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Join Date: Mar 2009

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ninadg

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String compare with Form field

Mar 11th, 2009

I am new to JSP and am having trouble comparing string with the value in a form field submitted.

The following is the code that I am executing through Tomcat and is not giving me the desired result:

 Help with Code Tags 
 java Syntax (Toggle Plain Text) 
<%
String myvar = request.getParameter("var1");
boolean first = false;
if (myvar == null) {  
        first = true;
} else {
        if (myvar == "compareme") out.println("string matches"); else out.println("string MISMATCH");                  
}
%>
<html>
<head><title>String compare with Form Input</title></head>
<body>
<h2>If you enter input as "compareme", I should say "MATCH", 
else "MISMATCH"</h2>
<% if (! first) { %>
Input was <%= myvar %> <br>
<% }  %>
<hr>
<form>Please enter a string <input name=var1>
 and <input type=submit></form>
</body>
</html>
<%
String myvar = request.getParameter("var1");
boolean first = false;
if (myvar == null) {  
        first = true;
} else {
        if (myvar == "compareme") out.println("string matches"); else out.println("string MISMATCH");                  
}
%>
<html>
<head><title>String compare with Form Input</title></head>
<body>
<h2>If you enter input as "compareme", I should say "MATCH", 
else "MISMATCH"</h2>
<% if (! first) { %>
Input was <%= myvar %> <br>
<% }  %>
<hr>
<form>Please enter a string <input name=var1>
 and <input type=submit></form>
</body>
</html>

You will notice that even though the correct string "compareme" is submitted in the form, the string comparison still fails. I have tried appending .toString() and .trim() to myvar but that has not helped either.

I am obviously missing something very basic in JSP. Please help.

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Re: String compare with Form field

Mar 11th, 2009

You are missing something basic in Java which is why you should leave JSP and practice more:

 Help with Code Tags 
 JSP Syntax (Toggle Plain Text) 
if (myvar.equals("compareme")) 
   out.println("string matches"); 
else 
   out.println("string MISMATCH");
if (myvar.equals("compareme")) 
   out.println("string matches"); 
else 
   out.println("string MISMATCH");