JSP request.getParameter字符串

Question

I have the following page in JSP:

<%
    String req = request.getParameter("req");

    if (req == "Start")
        // Do something here
%>

<form>
    <input type="submit" name="req" value="Start" />
</form>

But when I press the Start button it seems that req value is not equal to Start , and the code does not enters the if statement.

What can be wrong?

Answer 1

You should write

 if (req != null && req.equals("Start"))

instead of

 if (req == "Start")

Answer 2

Use if("Start".equals(request.getParameter("req")))

Even if request.getParameter("req") is null, you won't receive any errors.

Answer 3

if (req == "Start") comparing the references of both object thats why you are not entering in if block. Use String class equals() method which compare the values instead of reference.