利用反射載入類

反射：java.lang.reflect

要被載入的類：

package eg.fortest;

public class WaitingforLoader {

	private String str;
	static{
		System.out.println("loading WaitingforLoader");		
	}
	public WaitingforLoader() {
		str="empty";
		System.out.println("Constructor of WaitingforLoader without anything.");
	}
	public WaitingforLoader(String str) {
		this.str=str;
		System.out.println("Constructor of WaitingforLoader with "+str);
	}
	public void getStr(int i){
		System.out.println("str="+str);
	}
}

　　載入運行的類：

package factory.classfactory;

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

//import eg.fortest.WaitingforLoader;不需要這條語句

public class LoadMyClass {

	public static void main(String[] args) 
			throws ClassNotFoundException,
			InstantiationException,IllegalAccessException, 
			NoSuchMethodException, SecurityException, 
			IllegalArgumentException, InvocationTargetException
	 {

		System.out.println("Program start.");

		/**
		 * 類的載入、鏈接、初始化。
		 */
		Class<?> clazz = Class.forName("eg.fortest.WaitingforLoader");

		/**
		 * 對象的創建
		 */
		Object myvar1 = clazz.newInstance();
		Constructor cor=clazz.getConstructor(String.class);
		Object myvar2 =cor.newInstance("string Parameter");
		/**
		 * 方法調用
		 */
		Method m =clazz.getMethod("getStr",int.class);		
		m.invoke(myvar2, 1);
	}

}

　　輸出的結果：

Program start.
loading WaitingforLoader
Constructor of WaitingforLoader without anything.
Constructor of WaitingforLoader with string Parameter
str=string Parameter