反射的三种方式，获取成员变量的信息

反射：

获得包名、类名
clazz.getPackage().getName()//包名
clazz.getSimpleName()//类名
clazz.getName()//完整类名
！！成员变量定义信息
getFields()//获得所有公开的成员变量，包括继承的变量
getDeclaredFields()//获得本类定义的成员变量，包括私有,不包括继承的变量
getField(变量名)
getDeclaredField(变量名)

代码：
Demo01.java

package com.fanjia.day20200824;

import java.lang.reflect.Field;

/**
 * Created by FanJia on 2020/8/24 18:50
 */
public class Demo01 {
    
    
    public static void main(String[] args) throws ClassNotFoundException, NoSuchFieldException {
    
    
        Class<?> student = Class.forName("com.fanjia.day20200824.Student");
        //Class<Student> studentClass = Student.class;
        Class<? extends Student> aClass = new Student().getClass();
        System.out.println(student.getName());

        System.out.println(student.getPackage().getName());
        System.out.println(student.getSimpleName());
        Field id = student.getField("id");
        System.out.println(id);
        Field name = student.getDeclaredField("name");
        System.out.println(name);
        Field[] fields = student.getFields();
        System.out.println("=======================");
        for(Field field : fields){
    
    
            System.out.println(field);
        }
        System.out.println("===========================");
        Field[] declaredFields = student.getDeclaredFields();
        for (Field field : declaredFields){
    
    
            System.out.println(field);
        }


    }
}

Student.java

package com.fanjia.day20200824;

/**
 * Created by FanJia on 2020/8/24 18:52
 */
public class Student {
    
    
    public int id=1;
    private String name;

    public Student() {
    
    
    }

    public Student(int id) {
    
    
        this.id = id;
    }

    public Student(int id, String name) {
    
    
        this.id = id;
        this.name = name;
    }

    public int getId() {
    
    
        return id;
    }

    public void setId(int id) {
    
    
        this.id = id;
    }

    public String getName() {
    
    
        return name;
    }

    public void setName(String name) {
    
    
        this.name = name;
    }

    @Override
    public String toString() {
    
    
        return "Student{" +
                "id=" + id +
                ", name=" + name +
                '}';
    }
}