use.java

java相关的j2me,j2se的一些相关资料

package test;
import java.lang.reflect.*;

public class Use {
    public void use1(){
        Test1 t2 = new Test2();
        t2.f1();  //打印出:Test2
        Test1 t3 = (Test1)(new Test3("")); //打印出:Test2 Constructor
        t3.f1();  //打印出:Test3
    }
    
    public void use2(Test1 t1){ t1.f1(); }
    
    public void use3(String className) throws NoSuchMethodException, IllegalAccessException, InvocationTargetException, ClassNotFoundException{
        Class c = Class.forName(className);
        Method m = c.getDeclaredMethod("f2");
        //m.setAccessible(true);
        m.invoke(null);  //此种调用法要求对应的方法必须是静态的,否则会出错.
    }
    
    public void use4(Class c) throws IllegalAccessException, NoSuchMethodException, InvocationTargetException, InstantiationException{
        Method m = c.getDeclaredMethod("f2");
        m.invoke(null);  //此种调用法要求对应的方法必须是静态的,否则会出错.
        m = c.getDeclaredMethod("f1");
        m.invoke(c.newInstance(),new Object[]{});//此种调用法要求对应的类必须要有空的构造函数.
    }
    
    public void use5(Class c) throws InstantiationException, IllegalAccessException{
        Test1 t3 = (Test1)c.newInstance(); //要求对应的类必须要有空的构造函数
        t3.f1();
    }
    
    public static void main(String args[]) throws NoSuchMethodException, IllegalAccessException, ClassNotFoundException, InvocationTargetException, InstantiationException{
        Use u = new Use();
        u.use1();
        u.use2(new Test3("")); //打印出:Test2 Constructor
        //                                Test3
        u.use3("test.Test3");   //打印出:Test3 f2
        u.use4(Test3.class);   //打印出:Test3 f2
        //                                Test3
        u.use5(Test3.class);   //打印出:Test3
    }
}