3、反射-Field

public class Person {
    String name;
    private int age;


    public Person() {
    }
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

      Class clazz = Class.forName("cn.com.mrchengs.field.Person");

        //1、获取所有字段
        //共有的私有的均能获取
        Field[] fields = clazz.getDeclaredFields();
        for (Field field : fields){
            System.out.println(field.getName());
        }

        //2、获取指定名字的Field
        //共有的私有的都能获取得到
        Field field = clazz.getDeclaredField("age");
        System.out.println(field.getName());
        Field field1 = clazz.getDeclaredField("name");
        System.out.println(field1.getName());

       //3、获取指定对象的Field的值
        Person person = new Person("MrChengs",22);
        Field field = clazz.getDeclaredField("age");
　　　　　//对于私有的属性需要设置
        field.setAccessible(true);
        Field field1 = clazz.getDeclaredField("name");
        Object age = field.get(person);
        Object name = field1.get(person);
        System.out.println(age);
        System.out.println(name);

        //4、设置值
        Person person = new Person("MrChengs",22);
        Field field = clazz.getDeclaredField("age");
        field.setAccessible(true);
        field.set(person,33);
        System.out.println(field.get(person));