public class Test09 {
public static void main(String[] args) throws ClassNotFoundException, IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException, NoSuchFieldException {
//获得Class对象
Class<?> aClass = Class.forName("com.fl.reflection.User");
//构造一个对象
User user = (User) aClass.newInstance(); //本质是调用了User的无参构造器
System.out.println(user);
//通过构造器创建对象
Constructor<?> declaredConstructor = aClass.getDeclaredConstructor(String.class, int.class, int.class);
User user1 = (User) declaredConstructor.newInstance("小白", 001, 18);
System.out.println(user1);
//通过反射调用普通方法
User user2 = (User)aClass.newInstance();
//通过反射获取一个方法
Method setName = aClass.getDeclaredMethod("setName", String.class);
setName.invoke(user2,"AAA");
System.out.println(user2.getName());
//通过反射操作属性
User user3 = (User)aClass.newInstance();
Field name = aClass.getDeclaredField("name");
//不能直接操作私有属性,我们需要关闭程序的安全检测, 属性或方法的setAccessible(true)
name.setAccessible(true);
name.set(user3,"BBB");
System.out.println(user3.getName());
}
}