envconfig

Environment Variable Based Configuration for Java

Inspired by the excellent Golang library github.com/kelseyhightower/envconfig

To use this facility, simply add annotations to desired configuration variables in a class. Then call the EnvConfig.load() method to statically set the variables. Variables can be any primitive type and strings. Note that arrays and maps are not currently supported.

The name variable in the annotation specifies which environment variable should be loaded into the field.

package com.example;

import com.sentinel.config.Config;
import com.sentinel.config.EnvConfig;

public class Configuration {
    @Config(name="INT_VAR", defaultValue="1")
    public static int intVar;
    
    @Config(name="DOUBLE_VAR", defaultValue="1.0")
    public static double doubleVar;
    
    @Config(name="STRING_VAR", defaultValue="Hello World!")
    public static String stringVar;
}

public static void main(String[] args) {
    EnvConfig.load(Configuration.class);
}

#!/bin/bash
export INT_VAR="2"
export DOUBLE_VAR="3.14"
export STRING_VAR="Goodbye Cruel World!"

By sourcing the script prior to execution, the values in the Configuration class will be set according to the variables in the shell.