If you are displaying values in some input boxes in your current servlet then you can reterive the same in the next servlet using(provided the input boxes are inside the <form> tag),
Request.getParameter(String parameterName) method.
The second case is, if you are displaying it as labels in the current servlet then u can use hidden fileds in your current servlet and populate the hidden fields with the values. Then on Submit of the form you can retrive the same values in your next servlet using the same method mentioned above.
If you are not using the submit button, instead if you are using a hyper link to go to the next servlet then you can append the values at the end of the URL as follows(example), http://localhost/WebApp/Servlet2?userName=xyz,
then you can retrive the id value in your next servlet as follows,
String name = request.getParameter(userName);
Hope this helps you.