Problem with cache

[matteo belloni]

I've a servlet that write on a file. If the Tomcat is running the first time the application rewrite the file, the other time this file is appended but, If I first shutdown the webserver, the information in a file isn't appended and the application function correctly. This appen because this file is keeping in the web server's cache. How can I solve this problem and writing every time on a file instead of append the information? I must modify web.xml? And how? Please help me. Thanks in advance