java中Property类配置文件，反射创建实例并调用这个类的方法

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


public class Client4 {
    public static void main(String[] args) throws Exception {
        // 最Low的方法
//        PrinterDriverV1 v1 = new PrinterDriverV1();
//        v1.print("Low");
//        
//        // 
//        PrinterDriver v2 = new PrinterDriverV1();
//        v2.print("2 Low");


        Properties pps = new Properties();
        pps.load(new FileInputStream("d:/driver.properties"));
        Class<?> driverClass = Class.forName(pps.getProperty("PrinterDriver"));
        PrinterDriver v3 = (PrinterDriver)driverClass.newInstance();
        v3.print("High");
    }
}


interface PrinterDriver {
    public void print(String content);
}


class PrinterDriverV1 implements PrinterDriver{
    @Override
    public void print(String content) {
        System.out.println("Printer V1 content:" + content);
    }
}


class PrinterDriverV2 implements PrinterDriver{
    @Override
    public void print(String content) {
        System.out.println("Printer V2 content:" + content);
    }
}


class PrinterDriverV3 implements PrinterDriver{
    @Override
    public void print(String content) {
        System.out.println("Printer V3 content:" + content);
    }

}

driver.properties文件

PrinterDriver=PrinterDriverV2