I have created a report in jaspersoft studio, in this reports I have four fields and one parameter, the parameter is to be receive the date to select records in mysql db sent by hashmap in my servlet. The problem is that, when I click in the preview button of jaspersoft studio screen and I inform the date desired, the preview show me the records of my mysql db without problem. But, when I execute my servlet to generate the report I not generate the report and I do not receive any type of error.
You have a processRequest(...) method declared. And in its comments it says
This is not correct. It actually does nothing. So if you submit a GET request, you'll get nothing. (Which appears to be what is happening.) You will only get something returned if you submit a POST request. (Warning: I haven't looked at your doPost(...) method in case I was right already.)
It's better not to use the trick where doGet and doPost both call a method which does the actual work. For one thing you normally shouldn't have GET and POST requests which do the same thing.
When I search the web I see a lot of pages which suggest that a <button> element always uses the GET method, regardless of what the <form> says which contains the <button>. They also suggest you use <input type="submit"> instead.
If they are right, and I expect they are, then my original post which points out that your servlet does nothing for GET requests is also right.