How do I send data between servlets?

Question

I am pretty new to servlets and web development in general.

So basically I have a servlet that queries a database and returns some values, like a name. What I want is to turn the name into a link that opens a details page for that name (which another servlet would handle). How can I send the name to the other servlet so it can query a database for the relevant details?

Maybe I'm taking the wrong approach?

Edit: I am using Tomcat 5.5

score 3 · Accepted Answer · edited May 23 '17 at 11:44

3

Pass it as request parameter.

Either add it to the query string of the URL of the link to the other servlet which is then available by request.getParameter("name") in the doGet() method.

<a href="otherservlet?name=${name}">link</a>

Or add it as a hidden input field in a POST form which submits to the other servlet which is then available by request.getParameter("name") in the doPost() method.

<form action="otherservlet" method="post">
    <input type="hidden" name="name" value="${name}" />
    <input type="submit" />
</form>

2

Yep. Servlets do not usually communicate with each other. They only serve requests to clients. – cherouvim Mar 19 '11 at 19:35
Sorry for another newbie question but what does "${whatever}" mean/do? – Mojo Chinto Mar 19 '11 at 21:07
Thanks this actually worked well for me! I used the getParameter in the doGet() method. However, I did not need to add "${}" around the name. – Mojo Chinto Mar 19 '11 at 21:39

score 0 · Answer 2 · answered Mar 19 '11 at 19:32

0

Not sure if I understand correctly, but you may look at javax.servlet.RequestDispatcher and forward the url to the second servlet. The url could be created using the name:

http://myhost.mydomain/my.context/servlet2.do?name=John

answered Mar 19 '11 at 19:32

Riccardo Cossu

2,699
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1

He want to pass it by a link. Plus, forwarding isn't a good idea for inter servlet interaction. Including is better, see also http://stackoverflow.com/questions/3024949/how-do-i-execute-a-sequence-of-servlets – BalusC Mar 19 '11 at 19:34

score 0 · Answer 3 · answered Mar 19 '11 at 21:55

0

I would create the URL either in the first servlet or in a client using a configurable template for the URL. This way both servlets are clearly separated - you can even have each one on different machine.

answered Mar 19 '11 at 21:55

Rostislav Matl

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How do I send data between servlets?

3 Answers3

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