利用反射获取父类，接口信息

这个例子好似来自tij-4，（太久没更新博客了，不记得了）。
这个例子主要是用来说明，运行时能获取的被实现的接口，被继承的类的信息。
在实际开发中是一个蛮常用的手段，比如在框架中要检查某个类是否实现了某一接口。

package org.iteye.bbjava.runtimeinformation;




class Toy {

	/**
	 * It's a contructor of Toy class,it could be used contructing an object of
	 * Toy at runtime.
	 * */
	public Toy() {
		// TODO Auto-generated constructor stub
	}

	public Toy(int i) {

	}
}

interface HasBatteries {

}

interface Waterproof {

}

interface Shoots {

}

class FancyToy extends Toy implements HasBatteries, Waterproof, Shoots {
	FancyToy() {
		super(1);
	}
}

public class ToyTest {
	static void printInfo(Class cc) {
		System.out.println("Class name: " + cc.getName() + " is interface?["
				+ cc.isInterface() + "]");
		System.out.println("Simple name: " + cc.getSimpleName());
		System.out.println("Canonical name: " + cc.getCanonicalName());
	}

	public static void main(String[] args) {
		Class c = null;
		try {
			c = Class.forName("org.iteye.bbjava.runtimeinformation.FancyToy");

		} catch (Exception e) {
			System.out.println("Can't find FancyToy");
			System.exit(1);
		}
		printInfo(c);

		for (Class face : c.getInterfaces()) {
			printInfo(face);
			Class up = c.getSuperclass();
			Object obj = null;
			try {
				obj = up.newInstance();

			} catch (InstantiationException e) {
				System.out.println("Can't getInstance from up object");
				System.exit(1);
			} catch (IllegalAccessException e) {
				System.out.println("Can't access");
				System.exit(1);
			}
			printInfo(obj.getClass());
		}
	}
}

console info:

引用

Class name: org.iteye.bbjava.runtimeinformation.FancyToy is interface?[false]
Simple name: FancyToy
Canonical name: org.iteye.bbjava.runtimeinformation.FancyToy
Class name: org.iteye.bbjava.runtimeinformation.HasBatteries is interface?[true]
Simple name: HasBatteries
Canonical name: org.iteye.bbjava.runtimeinformation.HasBatteries
Class name: org.iteye.bbjava.runtimeinformation.Toy is interface?[false]
Simple name: Toy
Canonical name: org.iteye.bbjava.runtimeinformation.Toy
Class name: org.iteye.bbjava.runtimeinformation.Waterproof is interface?[true]
Simple name: Waterproof
Canonical name: org.iteye.bbjava.runtimeinformation.Waterproof
Class name: org.iteye.bbjava.runtimeinformation.Toy is interface?[false]
Simple name: Toy
Canonical name: org.iteye.bbjava.runtimeinformation.Toy
Class name: org.iteye.bbjava.runtimeinformation.Shoots is interface?[true]
Simple name: Shoots
Canonical name: org.iteye.bbjava.runtimeinformation.Shoots
Class name: org.iteye.bbjava.runtimeinformation.Toy is interface?[false]
Simple name: Toy
Canonical name: org.iteye.bbjava.runtimeinformation.Toy

评论

2 楼 BBjava 2012-11-16  

spiniper 写道

一般利用反射获去获取父类并不是一件常用的功能
判断一个对象是否属于一个类使用 cm instanceof CipherManager这种方式
判断一个类是否为某个类的子类使用 CipherManager.class.isAssignableFrom(SymAsymCipherManager.class);
这种方式。
而且装载类，通常我喜欢用ClassLoader来完成，例如:
cm.getClass().getClassLoader().loadClass("org.spiniper.commons.tool.cipher.SymAsymCipherManager")
当然，这看个人习惯了。

这里主要表达的还是想看看父类、接口里的信息。
instanceof 操作足够胜任了。

1 楼 spiniper 2012-11-16  

一般利用反射获去获取父类并不是一件常用的功能
判断一个对象是否属于一个类使用 cm instanceof CipherManager这种方式
判断一个类是否为某个类的子类使用 CipherManager.class.isAssignableFrom(SymAsymCipherManager.class);
这种方式。
而且装载类，通常我喜欢用ClassLoader来完成，例如:
cm.getClass().getClassLoader().loadClass("org.spiniper.commons.tool.cipher.SymAsymCipherManager")
当然，这看个人习惯了。