java反射机制提供哪些功能

@Test

public void test1() throws Exception {

    Class<Person> clazz = Person.class;

    //1.通过反射，创建Person类对象

    Constructor<Person> cons = clazz.getConstructor(String.class, int.class);

    Person person = cons.newInstance("Tom", 12);

    System.out.println(person);//Person{name='Tom', age=12}

    //2.通过反射，调用对象指定的属性、方法

    //调用属性

    Field age = clazz.getDeclaredField("age");

    age.setAccessible(true);

    age.set(person, 10);

    System.out.println(person.toString());//Person{name='Tom', age=10}

    //调用方法

    Method show = clazz.getDeclaredMethod("show");

    show.invoke(person);//my name is Tom and age is 10

    System.out.println("===================================");

    //通过反射，可以调用Person类的私有结构的。比如：私有的构造器、方法、属性

    //调用私有的构造器

    Constructor<Person> cons1 = clazz.getDeclaredConstructor(String.class);

    cons1.setAccessible(true);

    Person p1 = cons1.newInstance("Bruce");

    System.out.println(p1);//Person{name='Bruce', age=0}

    //调用私有的属性

    Field name = clazz.getDeclaredField("name");

    name.setAccessible(true);

    name.set(p1, "Jarry");

    System.out.println(p1);

    //调用私有的方法

    Method nation = clazz.getDeclaredMethod("nation", String.class);

    nation.setAccessible(true);

    Object nation1 = (String) nation.invoke(p1, "China");//相当于String nation = p1.showNation("China")

    System.out.println(nation1);//I come from China

}