2022.07.23 王茜 学习笔记
作者：互联网
final关键字
* public公有的
* protected受保护的
* 默认的，友好的
* private私有的
*final关键字
* final可以修饰的结构：
* 1、类 public final class
* 最终类，终级类
* 2、属性 private final String name
* 常量，不能改变
* 常量的命名规则：单词的所有字母大写，如果是多个单词，中间用下划线分割
* 常量不能只声明不赋值
* 3、方法 private final void show()
* 不能重写
*Object：最顶级父类
祖先类：Object（最顶级父类）
* 如果一个类没有明确的写出它的父类是谁，那它的父类就是Object
*
* Object类中有11个方法
* 1.hashCode();它的返回值实际上就是对象运行时的内存地址。
* hash算法：一般翻译“散列”，把任意长度的输入，通过一个散列算法变换成固定长度的输出，输出结果就是散列值。
* 密码加密MD5加密
* SHA家族
* 2.equals()，和==没区别，比地址。为了让子类重写。
* 3.toString()，转换成字符串。当我们直接使用对象时，会默认调用toString()方法。
* 为了让子类重写
* 4.finalize()，垃圾回收的方法
* 5.clone()，克隆，必须实现Cloneable接口今天我们学习了final关键字和Object的使用方法，为了巩固练习，我们做了下面这道题：
信息录入：
录入老师信息，身份证号相同的就是同一个人。重写toString方法
录入学生信息，身份证号相同的就是同一个人。重写toString方法
一个老师教多个学生。
分析：使用，has，is
老师类中，有一个teach方法，最终会展示出他教哪些学生。
学生类中，有一个study方法，最终会展示出他跟着哪个老师学习。
学校类，有很多老师，很多学生，最终会展示出哪些老师和哪些学生。
在Demo类中测试相关功能！
1.创建一个老师，再来一个老师，比较一下。
2.学生比较。
3.老师教的学生信息
答案：
public class Demo
public class Demo {
public static void main(String[] args) {
// 第一个老师和他的学生们
Teacher teacher = new Teacher("xyz",40,"789789","8001");
Student s1 = new Student("aaa",20,"123456","1001",teacher);
Student s2 = new Student("bbb",20,"123457","1002",teacher);
Student s3 = new Student("ccc",20,"123458","1003",teacher);
Student s4 = new Student("ddd",20,"123459","1004",teacher);
Student s5 = new Student("eee",20,"123450","1005",teacher);
// System.out.println(s1);
// 第一个老师和他的学生们的关系
Student [] stus = new Student[]{s1,s2,s3,s4,s5};
teacher.setStus(stus);
// 第二个老师和他的学生们
Teacher teacher2 = new Teacher("qwer",40,"456456","8002");
Student s6 = new Student("fff",22,"223456","2001",teacher2);
Student s7 = new Student("ggg",22,"223457","2002",teacher2);
Student s8 = new Student("hhh",22,"223458","2003",teacher2);
Student s9 = new Student("iii",22,"223459","2004",teacher2);
Student s10 = new Student("jjj",22,"223450","2005",teacher2);
// 第二个老师和他的学生们的关系
Student [] stus2 = new Student[]{s6,s7,s8,s9,s10};
teacher2.setStus(stus2);
Teacher [] teachers = new Teacher[]{teacher,teacher2};
// 所有学生的数组
Student [] students = new Student[]{s1,s2,s3,s4,s5,s6,s7,s8,s9,s10};
School school = new School();
school.setTeacher(teachers);
school.setStudents(students);
// school.showTeachers();
school.showStudents();
}
}public class Person
public class Person {
private String name;
private Integer age;
private String cardId;
public Person() {
}
public Person(String name, Integer age, String cardId) {
this.name = name;
this.age = age;
this.cardId = cardId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getCardId() {
return cardId;
}
public void setCardId(String cardId) {
this.cardId = cardId;
}
@Override
public boolean equals(Object obj) {
Person person = (Person) obj;
if(this == person){
return true;
}
if(this.cardId.equals(person.cardId)){
return true;
}
return false;
}
@Override
public String toString() {
return "Person{" +
"name='" + name + '\'' +
", age=" + age +
", cardId='" + cardId + '\'' +
'}';
}
}public class School
public class School {
private Teacher [] teacher;
private Student [] students;
public Teacher[] getTeacher() {
return teacher;
}
public void setTeacher(Teacher[] teacher) {
this.teacher = teacher;
}
public Student[] getStudents() {
return students;
}
public void setStudents(Student[] students) {
this.students = students;
}
public void showTeachers() {
// 老师和他对应的学生的信息
for (Teacher teacher1 : teacher) {
System.out.println(teacher1.teach());
}
}
public void showStudents() {
// 学生和他对应的老师的信息
for (Student student : students) {
System.out.println(student.study());
}
}
}public class Student extends Person
public class Student extends Person {
private String stuNo;
private Teacher teacher;
public Student() {
}
public Student(String name, Integer age, String cardId, String stuNo, Teacher teacher) {
super(name, age, cardId);
this.stuNo = stuNo;
this.teacher = teacher;
}
public String study(){
return this + "，\n 老师是：" + teacher;
}
public String getStuNo() {
return stuNo;
}
public void setStuNo(String stuNo) {
this.stuNo = stuNo;
}
public Teacher getTeacher() {
return teacher;
}
public void setTeacher(Teacher teacher) {
this.teacher = teacher;
}
@Override
public String toString() {
return super.toString() + "Student{" +
"stuNo='" + stuNo + "}";
}
}public class Teacher extends Person
import java.util.Arrays;
public class Teacher extends Person {
private String teaNo;
private Student [] stus;
public Teacher() {
}
public Teacher(String name, Integer age, String cardId, String teaNo) {
super(name, age, cardId);
this.teaNo = teaNo;
}
public String teach() {
return this + "，\n" + Arrays.toString(stus);
}
public String getTeaNo() {
return teaNo;
}
public void setTeaNo(String teaNo) {
this.teaNo = teaNo;
}
public Student[] getStus() {
return stus;
}
public void setStus(Student[] stus) {
this.stus = stus;
}
@Override
public String toString() {
return super.toString() + "Teacher{" +
"teaNo='" + teaNo;
}
}
标签：return,String,23,Teacher,teacher,Student,2022.07,public,王茜 来源： https://www.cnblogs.com/wx1019/p/16512761.html