package Chapter_6;

import java.util.Date;

public class YeekuObjectFactory {
    public static Object getInstance(String clsName){
        try{
            Class cls = Class.forName(clsName);
            return cls.newInstance();
        }catch (Exception e){
            e.printStackTrace();
            return null;
        }
    }

    public static void main(String args[]){
        Date d = (Date) YeekuObjectFactory.getInstance("java.util.Date");
//        甚至可以出現下面這種操作
//        JFrame jFrame = (Date) YeekuObjectFactory.getInstance("java.util.Date");
    }
}
 

在使用了泛型之後，可以方便地避免強制轉換地操作，如下

package Chapter_6;

import javax.swing.*;
import java.util.Date;

public class YeekuObjectFactoy2 {
    public static <T>T getInstance(Class<T> cls){
        try{
            return cls.newInstance();
        }catch (Exception e){
            e.printStackTrace();
            return null;
        }
    }

    public static void main(String args[]){
        Date d = YeekuObjectFactoy2.getInstance(Date.class);
        JFrame jFrame = YeekuObjectFactoy2.getInstance(JFrame.class);
    }
}