用Java动态加载类

Question

I have some weird requirment I need to load a class dynamically,

here I have an Interface

    public interface House
    {
       public Object loadHouseModel(String type);
       public Object loadHouseSpace(String type); 
     } 

now the desired class will implement this interface

     public class DuplexHouse implements House 
     {
        public Object loadHouseModel(String type)
        {
             ///Method body goes here
        }
        public Object loadHouseSpace(String type)
         {
             ///Method body goes here
         }
      }   

Now my requirement is that I need to load DuplexHouse or whatever the class which implements House

Requirment is that DuplexHouse class name I will get it from properties and All I know is The class name I get will Implement the House Interface. so my propertie looks like this type_house=xx.xx.xxx.DuplexHouse,xx.xx.xx.TruplexHouse,..etc

Based on the type of House I need to load corresponding house object

So in my main class Class cl = Class.forName(xx.xxx.xxx.DuplexHouse); My requirment is I want House Instance which internally holds DuplexHouse object How can I do that ??

Answer 1

First do Class.forName . This will give you the DuplexHouse class in the form of Class<?> . On that, do newInstance() . It will give you the instance of DuplexHouse in the form of an Object . Cast this to House and you have your DuplexHouse instance in the form of House .

This assumes (1) the DuplexHouse class in in the class path (2) DuplexHouse constructor takes zero arguments.

Answer 2

@Babel I could not quite understand your question, but you're able to check if an object is an instance of any class or interface with the instanceof keyword.

For example

boolean isLion = felineAnimal instanceof Lion boolean isWolf = canineAnimal instanceof Wolf