https://s3-us-west-2.amazonaws.com/secure.notion-static.com/80973f89-39ed-4fcd-a6f1-0d162f7eb2b6/IMG_0224.jpg

package top.ltyzqhh.Reflection;

//什么叫反射
public class Test01 extends Object{
    //通过反射获取类的class对象
    public static void main(String[] args) throws ClassNotFoundException {
        Class c1 = Class.forName("top.ltyzqhh.Reflection.User");
        System.out.println(c1);

        Class c2 = Class.forName("top.ltyzqhh.Reflection.User");
        Class c3 = Class.forName("top.ltyzqhh.Reflection.User");
        Class c4 = Class.forName("top.ltyzqhh.Reflection.User");

        //一个类在内存中只有一个class对象
        //一个类被加载后,类的整个结构都会被封装在class对象中
        System.out.println(c2.hashCode());
        System.out.println(c3.hashCode());
        System.out.println(c4.hashCode());
    }
}

//实体类 pojo, entity
class User{

    private String name;
    private int id;
    private int age;

    public User(){
    }

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

    public String getName() {
        return name;
    }

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

    public int getId() {
        return id;
    }

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

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

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

https://s3-us-west-2.amazonaws.com/secure.notion-static.com/2660ed91-4be7-4197-b6d8-f1b3970dd578/IMG_0225.jpg

理解:获取对象的类,还能获取其类的一些具体信息