- package reflect;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.util.Properties;
- interface fruit{
- public abstract void eat() ;
- }
- class Apple implements fruit{
- public void eat() {
- System.out.println("eat Apple");
- }
- }
- class orange implements fruit{
- public void eat() {
- System.out.println("eat orange");
- }
- }
- class init{
- public static Properties getPro() throws FileNotFoundException, IOException{
- Properties pro = new Properties() ;
- File f = new File("fruit.properties") ;
- if(f.exists()){
- System.out.println("有配置文件！");
- //从配置文件中读取键值对
- pro.load(new FileInputStream(f)) ;
- }else{
- System.out.println("没有配置文件！");
- pro.setProperty("apple", "reflect.Apple") ;
- pro.setProperty("orange", "reflect.orange") ;
- pro.store(new FileOutputStream(f), "FRUIT CLASS") ;
- }
- return pro ;
- }
- }
- class Factory{
- public static fruit getInstance(String className){
- fruit f = null ;
- try {
- //通过反射得到fruit的实例对象
- f = (fruit)Class.forName(className).newInstance() ;
- } catch (InstantiationException e) {
- e.printStackTrace();
- } catch (IllegalAccessException e) {
- e.printStackTrace();
- } catch (ClassNotFoundException e) {
- e.printStackTrace();
- }
- return f ;
- }
- }
- public class Hello {
- public static void main(String[] args) {
- try {
- Properties pro = init.getPro() ;
- fruit f = Factory.getInstance(pro.getProperty("apple")) ;
- if(f != null){
- f.eat() ;
- }
- } catch (FileNotFoundException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- } catch (IOException e) {
- // TODO Auto-generated catch block
- e.printStackTrace();
- }
- }
- }
结果为：
有配置文件！
eat Apple
