工厂模式
import java.io.*;
public class TestFactory{
public static void main(String[] args){
Animal a = Factory.createAnimal();
}
}
abstract class Animal{}
class Dog extends Animal{}
class Cat extends Animal{}
class Factory{
public Animal createAnimal(){
FileReader fr = new FileReader("config.txt");
BufferedReader in = new BufferedReader(fr);
String className = in.readLine();
in.close();
Class c = Class.forName(className);
Object o = c.newInstance();
return(Animal)o;
}
}