// 什么叫反射
public class Test02 {public static void main(String[] args) throws ClassNotFoundException {// 通过反射获取类的 Class 对象Class c1 = Class.forName("reflection.User");Class c2 = Class.forName("reflection.User");Class c3 = Class.forName("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(c1.hashCode()); // 460141958System.out.println(c2.hashCode()); // 460141958System.out.println(c3.hashCode()); // 460141958}
}// 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;}@Overridepublic String toString() {return "User{" +"name='" + name + '\'' +", id=" + id +", 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;}
}

https://www.bilibili.com/video/BV1p4411P7V3?p=5
https://www.bilibili.com/video/BV1p4411P7V3?p=6