Loading parameters or static contents into a program is easily handled in Java through the Properties class.
Create an instance of the Properties class and one instance of FileInputStream class that points to the configuration file.
The actual loading of the parameters are done through the method load() on the Properties object.
In the example below config parameters are read from the configuration file and then printed out.
This is what the sample configuration file (config/config.txt) looks like:
# Application configuration # Use '#' to write any comments in config file staticParam1=value1 staticParam2=value2
ConfigExample.java
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Enumeration;
import java.util.Properties;
/**
* ConfigExample.java
*
* @author www.codes.ssingh.in
*/
public class ConfigExample{
Properties config;
/**
* Loads configuration parameters from a textfile and print them out.
*/
public void loadConfigFile() {
//Load configuration file
String filename = "confing/config.txt";
config = new Properties();
try {
config.load(new FileInputStream(filename));
} catch (FileNotFoundException ex) {
ex.printStackTrace();
return;
} catch (IOException ex) {
ex.printStackTrace();
return;
}
//Print out the configuration parameters
Enumeration en = config.keys();
System.out.println("Application configuration: ");
while (en.hasMoreElements()) {
String key = (String) en.nextElement();
System.out.println(key + " -> " + config.get(key));
}
}
/**
* Starts the program
*
* @param args the command line arguments
*/
public static void main(String[] args) {
new ConfigExample().loadConfigFile();
}
}