title: how to stop repeat request in java webservice
body: <p>I created a SOAP webservice which convert received xml to mail content and send. Now sometime user sent same request twice and the same mail were sent twice. How to stop this? I think I can create a table to store the content and eachtime when a request received first check the table content then proceed. Is that work? I guess in the process I have to lock the table should I use synchronized method? or other better ways? Thx.    </p>