使计时器在属性文件中可配置

Question

I have a java program where I wrote a scheduler, or a timer where once it starts running. It will call the function every N minutes interval indefinitely. For now, I set N to 5 minutes.

I want to sent out this program in a form of jar file along with some sort of properties file where the tester or anyone else can configure N; so it's much more convenient and I do not have to change in the code itself.

This is an example:

public void schedule() throws Exception {

    Timer t=new Timer();
    t.scheduleAtFixedRate(
        new TimerTask() {
            @Override
            public void run() {
              // System.out.println("HELEOELE");

                try {
                    test.index();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        },
      0,
        300000);
}

In this case, N = 300000.

I am not too familiar with jar file but I do have a properties file with db connection created.

This is how I called the properties:

 Properties props=new Properties();


        InputStream in = getClass().getResourceAsStream("/config.properties");

        props.load(in);
        in.close();
        int value=Integer.parseInt(props.getProperty("value"));

So I would appreciate is there any way to do this?

Answer 1

You can read the properties file from the classpath in case it is present in your jar only.

Refer this: Load properties file in JAR?

But, if you wan't to store the properties file out of the jar and be able to make changes in it, then there are multiple options :

• store it on the file system at a specified location from where your code reads it.

• instead of a properties file, you can also have a system property defined, which stores the required value. But, you would have to restart your container every time you change the value.

• you could also consider reading this value directly from the database (optionally loading it into an in-memory cache). But, here, another API would needed to make changes in the database.

• Store it outside the jar. Refer the following link Read properties file outside JAR file