学生管理系统-面向对象（增删改查）

实体类

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

    public Student() {
    }

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

    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 int getAge() {
        return age;
    }

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

    public String getHobby() {
        return hobby;
    }

    public void setHobby(String hobby) {
        this.hobby = hobby;
    }

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

 接口

public interface StudentService {
    //添加用户
    void add(List<Student> list, Scanner sc);
    //查询用户
    void get(List<Student> list);
    //修改用户
    boolean set(List<Student> list,Scanner sc);
    //删除用户
    boolean delete(List<Student> list,Scanner sc);
}

实现类

public class StudentServiceImpl implements StudentService{
    //添加元素
    @Override
    public void add(List<Student> list, Scanner sc) {
        Student student = new Student();
        System.out.println("请输入姓名:");
        String name = sc.next();
        System.out.println("请输入年龄:");
        int age = sc.nextInt();
        System.out.println("请输入爱好:");
        String hobby = sc.next();
        student.setId(System.currentTimeMillis()+"");
        student.setName(name);
        student.setAge(age);
        student.setHobby(hobby);
        list.add(student); //将学生信息全部添加到list集合中
    }
    //查询元素
    @Override
    public void get(List<Student> list) {
        System.out.println("学生id"+"\t\t\t\t"+"姓名"+"\t\t"+"年龄"+"\t\t"+"爱好");
        for (int j = 0; j <list.size(); j++) {
            System.out.println(list.get(j).getId()+"\t\t"+list.get(j).getName()+"\t\t\t"+list.get(j).getAge()+"\t\t\t"+list.get(j).getHobby());
        }
    }
    //修改元素
    @Override
    public boolean set(List<Student> list,Scanner sc) {
        System.out.println("请输入姓名:");
        String name3 = sc.next();
        if (list.size()==0){  //判断集合中长度是否为空
            System.out.println("查无此人");
        }
        for (int j = 0; j <list.size(); j++) {   //遍历集合中的元素
            if (name3.equals(list.get(j).getName())){  //判断用户输入的值和集合中的name是否相同
                Student student1 = list.get(j);   //将集合中的每个元素赋值给学生对象
                System.out.println(student1);
                System.out.println("请输入新的姓名:");
                String name4 = sc.next();
                student1.setName(name4);  //将用户输入的名字赋值给新用户
                System.out.println("修改成功!!!");
                return true;
            }
        }
        return false;
    }
    //删除元素
    @Override
    public boolean delete(List<Student> list, Scanner sc) {
        System.out.println("请输入姓名:");
        String name5 = sc.next();
        if (list.size()==0){   //判断用户输入的长度是否为空
            System.out.println("查无此人");
        }
        for (int j = 0; j <list.size(); j++) {
            if (name5.equals(list.get(j).getName())){   //判断用户输入的值和集合中的name是否相同
                list.remove(j);  //将集合的元素属性移除
                System.out.println("删除成功!!");
                return true;
            }
        }
        return false;
    }

}

测试类

public class Test {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("---------欢迎使用学生管理系统------------");
        //Map<String,Student> map = new HashMap<>();
        List<Student> list = new ArrayList<>();
        StudentServiceImpl studentService = new StudentServiceImpl();
        while (true) {
            System.out.println("1.添加学生");
            System.out.println("2.查询学生");
            System.out.println("3.修改学生");
            System.out.println("4.删除学生");
            System.out.println("5.退出系统");
            int i=0;  //用户只能输入整数类型,否则会报错
            try {
                i = sc.nextInt();
            } catch (Exception e) {
                throw new InputMismatchException("输入的格式错误");
            }
            switch (i){
                case 1:
                    studentService.add(list,sc);
                    break;
                case 2:
                    studentService.get(list);
                    break;
                case 3:
                    studentService.set(list, sc);
                    break;
                case 4:
                    studentService.delete(list, sc);
                    break;
                case 5:
                    System.out.println("感谢使用本系统!!!");
                    return;
                default:
                    System.out.println("输入编号错误");
                    break;
            }
        }

    }
 }