java 读取系统配置文件

import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class Test {

public static void main(String[] args) throws IOException {
Test t =new Test();
t.a();
}

public void a() throws IOException{
ClassLoader classLoader = getClass().getClassLoader();
String configFilePath = classLoader.getResource("config.properties").getFile();
FileInputStream is = null;
Properties dbproperties = new Properties();
is = new FileInputStream(configFilePath);
dbproperties.load(is);
String db_url = dbproperties.getProperty("db_url").toString();

System.out.println(db_url);
}
}