学生管理系统

Student类

public class Studnet {
    private String sid;
    private String name;
    private String age;
    private String address;

    public Studnet() {}

    public Studnet(String sid, String name, String age, String address) {
        this.sid = sid;
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public String getSid() {
        return sid;
    }

    public void setSid(String sid) {
        this.sid = sid;
    }

    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 getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

测试类

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

public class StudentManager {
    public static void main(String[] args) {
        ArrayList<Studnet> arrayList = new ArrayList<Studnet>();
        while (true) {
            System.out.println("--------欢迎来到学生管理系统--------");
            System.out.println("1、添加学生");
            System.out.println("2、删除学生");
            System.out.println("3、修改学生信息");
            System.out.println("4、查看所有学生");
            System.out.println("5、退出");
            System.out.println("请输入对应数字：");

            Scanner sc = new Scanner(System.in);
            int line = sc.nextInt();

            switch (line) {
                case 1:
                    addStudent(arrayList);
                    break;
                case 2:
                    deleteStudent(arrayList);
                    break;
                case 3:
                    updateStudent(arrayList);
                    break;
                case 4:
                    findAllStudent(arrayList);
                    break;
                case 5:
                    System.out.println("谢谢使用");
                    System.exit(0);

            }
        }
    }

    public static void addStudent(ArrayList<Studnet> arrayList) {
        Scanner sc = new Scanner(System.in);
        String sid;
        while (true) {
            System.out.println("请输入学号：");
            sid = sc.nextLine();
            boolean flag = isUsed(arrayList, sid);
            if (flag) {
                System.out.println("您输入的学号已被占用，请核实信息后输入！");
                return;
            } else {
                break;
            }
        }

        System.out.println("请输入姓名：");
        String name = sc.nextLine();
        System.out.println("请输入年龄：");
        String age = sc.nextLine();
        System.out.println("请输入居住地：");
        String address = sc.nextLine();

        Studnet s = new Studnet();
        s.setSid(sid);
        s.setName(name);
        s.setAge(age);
        s.setAddress(address);

        arrayList.add(s);
        System.out.println("添加学生成功！");

    }

    public static boolean isUsed(ArrayList<Studnet> arrayList, String sid) {
        boolean flag = false;
        for (int i = 0; i < arrayList.size(); i++) {
            Studnet s = arrayList.get(i);
            if (s.getSid().equals(sid)) {
                flag = true;
                break;
            }
        }
        return flag;
    }

    public static void findAllStudent(ArrayList<Studnet> arrayList) {
        if (arrayList.size() != 0) {
            System.out.println("学号\t\t\t姓名\t\t年龄\t\t居住地");
            for (int i = 0; i < arrayList.size(); i++) {
                Studnet s = arrayList.get(i);
                System.out.println(s.getSid() + "\t" + s.getName() + "\t" + s.getAge() + "岁\t\t" + s.getAddress());
            }
        } else {
            System.out.println("学生表为空，请输入信息后再查询！");
            return;
        }
    }

    public static void deleteStudent(ArrayList<Studnet> arrayList) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入你要删除的学生的学号");
        String sid = sc.nextLine();

        if (arrayList.size() == 0) {
            System.out.println("学生表为空，请先输入信息再执行删除操作！");
        } else {
            for (int i = 0; i < arrayList.size(); i++) {
                Studnet s = arrayList.get(i);
                if (s.getSid().equals(sid)) {
                    arrayList.remove(i);
                    System.out.println("删除成功！");
                    break;
                } else {
                    System.out.println("查无此人，请核对信息后再执行删除操作！");
                }
                break;
            }
        }
    }

    public static void updateStudent(ArrayList<Studnet> arrayList) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入要修改的学生的学号：");
        String sid = sc.nextLine();

        if (arrayList.size() == 0) {
            System.out.println("学生表为空，请先输入信息再执行修改操作！");
            return;
        } else {
            for (int i = 0; i < arrayList.size(); i++) {
                Studnet st = arrayList.get(i);
                if (st.getSid().equals(sid)) {
                } else {
                    System.out.println("查无此人，请核对信息后再执行修改操作！");
                    return;
                }
            }
        }

        System.out.println("请输入更新后的学号：");
        String sid0 = sc.nextLine();
        System.out.println("请输入更新后的姓名：");
        String name = sc.nextLine();
        System.out.println("请输入更新后的年龄：");
        String age = sc.nextLine();
        System.out.println("请输入更新后的居住地：");
        String address = sc.nextLine();

        Studnet s = new Studnet();
        s.setSid(sid0);
        s.setName(name);
        s.setAge(age);
        s.setAddress(address);

        for (int i = 0; i < arrayList.size(); i++) {
            Studnet st = arrayList.get(i);
            if (st.getSid().equals(sid)) {
                arrayList.set(i, s);
                System.out.println("修改成功！");
                break;
            } else {
                System.out.println("查无此人，请核对信息后再操作！");
                break;
            }
        }

    }

}