java - Properties setting via Servlet -

i want set data configures.properties via servlet. configures.properties locating in web-inf/classes. how i'm getting data:

public static string getdbpassword() {         properties prop = new properties();         try {             // load properties file             inputstream in = configures.class.getresourceasstream(input_file);             prop.load(in);              // property value             return prop.getproperty("dbpassword");          } catch (ioexception ex) {             ex.printstacktrace();         }         return null;     } 

but how set? how did:

public static void setdbpassword(string str) {             properties prop = new properties();             try {                 //load properties file                 inputstream in = configures.class.getresourceasstream(input_file);                 prop.load(in);                 prop.setproperty("dbpassword", str);                 prop.store(new fileoutputstream(input_file), null);              } catch (ioexception ex) {                 ex.printstacktrace();             }         } 

but i'm catching java.io.filenotfoundexception after this. think happens after prop.store(new fileoutputstream(input_file), null);. how should modify outputstream?

upd: how input_file looks:

private static final string input_file = "/config.properties"; 

your input_file resource path getresourceasstream resolve relative classpath, you're trying pass same string fileoutputstream constructor try , treat absolute path relative root of filesystem. these 2 different locations.

you use servletcontext.getrealpath("web-inf/classes" + input_file) path need fileoutputstream.

but higher level issue here shouldn't assume web application have write access web-inf, or directory exists on disk @ (e.g. if app running directly war rather directory unpacked on disk). if want store configuration data can change should go in file @ known location outside web app (the location of file init parameter) know have read , write permission. stops changes being overwritten when deploy new version of app.