Java知识【老师管理系统】

目录

1：老师管理系统（应用）

1.1：需求说明

1.2：实现步骤

1.3：代码实现

1：老师管理系统（应用）

1.1：需求说明

• 添加老师: 通过键盘录入老师信息(id，name，age，birthday)

  使用数组存储老师信息,要求老师的id不能重复

• 删除老师: 通过键盘录入要删除老师的id值,将该老师从数组中移除,如果录入的id在数组中不存在,需要重新录入

• 修改老师: 通过键盘录入要修改老师的id值和修改后的老师信息

  将数组中该老师的信息修改,如果录入的id在数组中不存在,需要重新录入

• 查询老师: 将数组中存储的所有老师的信息输出到控制台

1.2：实现步骤

环境搭建实现步骤

• 菜单搭建实现步骤

  1. 展示欢迎页面,用输出语句完成主界面的编写

  2. 获取用户的选择,用Scanner实现键盘录入数据

  3. 根据用户的选择执行对应的操作,用switch语句完成操作的选择

• 添加功能实现步骤

 查询功能实现步骤

删除功能实现步骤  修改功能实现步骤

• 系统优化

  • 把updateTeacher和deleteTeacherById中录入老师id代码抽取到一个方法(inputTeacherId)中 该方法的主要作用就是录入老师的id,方法的返回值为String类型

  • 把addTeacher和updateTeacher中录入老师信息的代码抽取到一个方法(inputTeacherInfo)中 该方法的主要作用就是录入老师的信息,并封装为老师对象,方法的返回值为Teacher类型

1.3：代码实现

 老师类

public class Teacher extends Person{
	private String id;
    private String name;
    private String age;
    private String birthday;
    String address;

    public Teacher() {
    }

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

    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;
    }

    public String getBirthday() {
        return birthday;
    }

    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }
}

TeacherController类

public class TeacherController {

    private Scanner sc = new Scanner(System.in);
    private TeacherService teacherService = new TeacherService();

    public void start() {

        teacherLoop:
        while (true) {
            System.out.println("--------欢迎来到 <老师> 管理系统--------");
            System.out.println("请输入您的选择: 1.添加老师  2.删除老师  3.修改老师  4.查看老师  5.退出");
            String choice = sc.next();
            switch (choice) {
                case "1":
                    // System.out.println("添加老师");
                    addTeacher();
                    break;
                case "2":
                    // System.out.println("删除老师");
                    deleteTeacherById();
                    break;
                case "3":
                    // System.out.println("修改老师");
                    updateTeacher();
                    break;
                case "4":
                    // System.out.println("查看老师");
                    findAllTeacher();
                    break;
                case "5":
                    System.out.println("感谢您使用老师管理系统, 再见!");
                    break teacherLoop;
                default:
                    System.out.println("您的输入有误, 请重新输入");
                    break;
            }
        }

    }

    public void updateTeacher() {
        String id = inputTeacherId();

        Teacher newTeacher = inputTeacherInfo(id);

        // 调用业务员的修改方法
        teacherService.updateTeacher(id,newTeacher);
        System.out.println("修改成功");
    }

    public void deleteTeacherById() {

        String id = inputTeacherId();

        // 2. 调用业务员中的删除方法, 根据id, 删除老师
        teacherService.deleteTeacherById(id);

        // 3. 提示删除成功
        System.out.println("删除成功");


    }

    public void findAllTeacher() {
        // 1. 从业务员中, 获取老师对象数组
        Teacher[] teachers = teacherService.findAllTeacher();

        // 2. 判断数组中是否有元素
        if (teachers == null) {
            System.out.println("查无信息, 请添加后重试");
            return;
        }

        // 3. 遍历数组, 取出元素, 并打印在控制台
        System.out.println("学号\t\t姓名\t年龄\t生日");
        for (int i = 0; i < teachers.length; i++) {
            Teacher t = teachers[i];
            if (t != null) {
                System.out.println(t.getId() + "\t" + t.getName() + "\t" + t.getAge() + "\t\t" + t.getBirthday());
            }
        }
    }

    public void addTeacher() {
        String id;
        while (true) {
            // 1. 接收不存在的老师id
            System.out.println("请输入老师id:");
            id = sc.next();
            // 2. 判断id是否存在
            boolean exists = teacherService.isExists(id);

            if (exists) {
                System.out.println("id已被占用, 请重新输入:");
            } else {
                break;
            }
        }

        Teacher t = inputTeacherInfo(id);

        // 5. 将封装好的老师对象, 传递给TeacherService继续完成添加操作
        boolean result = teacherService.addTeacher(t);

        if (result) {
            System.out.println("添加成功");
        } else {
            System.out.println("添加失败");
        }
    }

    // 录入老师id
    public String inputTeacherId(){
        String id;
        while(true){
            System.out.println("请输入id");
            id = sc.next();
            boolean exists = teacherService.isExists(id);
            if(!exists){
                System.out.println("您输入的id不存在, 请重新输入:");
            }else{
                break;
            }
        }
        return id;
    }

    // 录入老师信息, 封装为老师对象
    public Teacher inputTeacherInfo(String id){
        System.out.println("请输入老师姓名:");
        String name = sc.next();
        System.out.println("请输入老师年龄:");
        String age = sc.next();
        System.out.println("请输入老师生日:");
        String birthday = sc.next();

        Teacher t = new Teacher();
        t.setId(id);
        t.setName(name);
        t.setAge(age);
        t.setBirthday(birthday);

        return t;
    }
}

TeacherService类

public class TeacherService {

    private TeacherDao teacherDao = new TeacherDao();

    public boolean addTeacher(Teacher t) {
        return teacherDao.addTeacher(t);
    }

    public boolean isExists(String id) {
        // 1. 获取库管对象中的数组
        Teacher[] teachers = teacherDao.findAllTeacher();

        boolean exists = false;

        // 2. 遍历数组, 取出每一个元素, 进行判断
        for (int i = 0; i < teachers.length; i++) {
            Teacher teacher = teachers[i];
            if(teacher != null && teacher.getId().equals(id)){
                exists = true;
                break;
            }
        }

        return exists;
    }

    public Teacher[] findAllTeacher() {
        Teacher[] allTeacher = teacherDao.findAllTeacher();

        boolean flag = false;

        for (int i = 0; i < allTeacher.length; i++) {
            Teacher t = allTeacher[i];
            if(t != null){
                flag = true;
                break;
            }
        }

        if(flag){
            return allTeacher;
        }else{
            return null;
        }

    }

    public void deleteTeacherById(String id) {
        teacherDao.deleteTeacherById(id);
    }

    public void updateTeacher(String id, Teacher newTeacher) {
        teacherDao.updateTeacher(id,newTeacher);
    }
}

TeacherDao类

public class TeacherDao {

    private static Teacher[] teachers = new Teacher[5];

    public boolean addTeacher(Teacher t) {
        int index = -1;
        for (int i = 0; i < teachers.length; i++) {
            Teacher teacher = teachers[i];
            if(teacher == null){
                index = i;
                break;
            }
        }

        if(index == -1){
            return false;
        }else{
            teachers[index] = t;
            return true;
        }

    }

    public Teacher[] findAllTeacher() {
        return teachers;
    }

    public void deleteTeacherById(String id) {
        // 1. 查询id在数组中的索引位置
        int index = getIndex(id);
        // 2. 将该索引位置的元素, 使用null进行替换
        teachers[index] = null;
    }

    public int getIndex(String id){
        int index = -1;
        for (int i = 0; i < teachers.length; i++) {
            Teacher t = teachers[i];
            if(t != null && t.getId().equals(id)){
                index = i;
                break;
            }
        }

        return index;
    }

    public void updateTeacher(String id, Teacher newTeacher) {
        int index = getIndex(id);
        teachers[index] = newTeacher;
    }
}