Java学习记录

一段时间没有更新，~~~为了装作自己正在努力学习~~~随便放点东西
2022.3.9更新：
添加了继承的使用

简易控制台版学生管理系统

Student.java

package test;

public class Student {
    private String id;
    private String name;
    private String age;

    public Student() {
    }

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

    public String getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

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

    public String getAge() {
        return age;
    }

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

StudentsManager.java

package test;

import java.util.ArrayList;
import java.util.Scanner;

public class StudentsManager {
    static Scanner scan = new Scanner(System.in);

    public static void userUI() {
        System.out.println("--------欢迎使用学生管理系统--------");
        System.out.println("|         1.添加学生             |");
        System.out.println("|         2.修改学生             |");
        System.out.println("|         3.删除学生             |");
        System.out.println("|         4.展示所有学生          |");
        System.out.println("|         5.退出系统             |");
        System.out.println("---------------------------------");
        System.out.print("请输入你的选择：");
    }

    public static boolean choose(ArrayList<Student> students, boolean OK) {
        String choose = scan.nextLine();
        switch (choose) {
            case "1":
                addStudent(students);
                break;
            case "2":
                setStudent(students);
                break;
            case "3":
                delStudent(students);
                break;
            case "4":
                allStudent(students);
                break;
            case "5":
                OK = false;
            break;
            default:
                System.out.println("没有该选项！");
        }
        return OK;
    }

    public static void addStudent(ArrayList<Student> students) {
        do {
            System.out.println("请输入学号：");
            String id = scan.nextLine();
            id = isTure(students, id);
            System.out.println("请输入姓名：");
            String name = scan.nextLine();
            System.out.println("请输入年龄：");
            String age = scan.nextLine();

            if (id.length() == 0 || name.length() == 0 || age.length() == 0) {
                System.out.println("有数据未输入！");
                return;
            } else {
                Student student = new Student(id, name, age);
                students.add(student);
                System.out.println("是否继续录入（y/n）");
            }
        } while (scan.nextLine().equals("y"));
    }

    private static String isTure(ArrayList<Student> students, String id) {
        Student student;
        for (int i = 0; i < students.size(); i++) {
            student = students.get(i);
            while (student.getId().equals(id)) {
                System.out.println("学号重复！请重新输入：");
                id = scan.nextLine();
            }
        }
        return id;
    }

    public static void setStudent(ArrayList<Student> students) {
        System.out.println("请输入要修改的学生学号：");
        String id = scan.nextLine();

        Student student;

        for (int i = 0; i < students.size(); i++) {
            student = students.get(i);
            if (student.getId().equals(id)) {
                System.out.println("请输入新学号：");
                String new_id = scan.nextLine();
                id = isTure(students, new_id);
                System.out.println("请输入新姓名：");
                String name = scan.nextLine();
                System.out.println("请输入新年龄：");
                String age = scan.nextLine();

                student.setId(new_id);
                student.setName(name);
                student.setAge(age);

                students.set(i, student);
                return;
            }
        }
        System.out.println("未找到该学生学号，请检查是否正确！");
    }

    public static void delStudent(ArrayList<Student> students) {
        System.out.println("请输入要删除的学生学号：");
        String id = scan.nextLine();

        Student student;

        for (int i = 0; i < students.size(); i++) {
            student = students.get(i);
            if (student.getId().equals(id)) {
                students.remove(i);
                System.out.println("删除成功！");
                return;
            }
        }
        System.out.println("未找到该学生学号，请检查是否正确！");
    }

    public static void allStudent(ArrayList<Student> students) {
        Student student;
        System.out.println("学号\t姓名\t\t年龄");
        if (students.size() == 0) {
            System.out.println("没有学生信息！");
            return;
        }
        for (int i = 0; i < students.size(); i++) {
            student = students.get(i);
            System.out.println(student.getId() + "\t" + student.getName() + "\t" + student.getAge() + "\t");
        }
    }
}

Manager.java

import java.util.ArrayList;

public class Manager extends StudentsManager{
    static boolean OK = true;
    public static void main(String[] args) {
        ArrayList<Student> students = new ArrayList<>();
        while (OK){
            userUI();
            OK = choose(students,OK);
        }
        System.out.println("感谢使用！");
    }
}