java update properties file run time

Question

i am writing standalone java app for production monitoring. once it starts running the api is configured for default values which is set in .properties file. in running state the api's configuration can be changed and the .properties file should be updated accordingly. is there a way to achieve this ? or are there any other approaches to implement this ?

Thanks in advance

Answer 1

The Java Properties class (api here) specifies "load" and "store" methods which should do exactly that. Use FileInputStream and FileOutputStream to specify the file to save it into.

Answer 2

You could use a very simple approach based on the java.util.Properties class which has indeed a load and store methods that you can use in conjunction with a FileInputStream and FileOutputStream:

But actually, I'd recommend to use an existing configuration library like Commons Configuration (amongst others). Check the Properties Howto to see how to load, save and automatically reload a properties file using its API.

Answer 3

In addition to the load and store method of the Properties class, you can also use the Apache Commons Configuration library, which provides functions to easily manipulate configuration files (and not only .properties files).

Answer 4

java.util.Properties doesn't provide runtime reloading out-of-the-box as far as I know. Commons Configuration provides support for reloading configuration at runtime. The reload strategy can be configured by setting a ReloadingStrategy on the PropertiesConfiguration object. It also offers various other useful utilities for making your application configurable.