JavaSE-9.2【学生管理系统】

package day9.student_management_system;

/*
快捷键：alt+insert，快速生成构造方法、set&get等
 */

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

    public Student() {
    }

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

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

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

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

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

    public String getSid() {
        return sid;
    }

    public String getName() {
        return name;
    }

    public String getAge() {
        return age;
    }

    public String getAddress() {
        return address;
    }
}

package day9.student_management_system;

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

public class StudentManager {

    public static void main(String[] args) {
        ArrayList<Student> arrayList = new ArrayList<Student>();

        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");
            System.out.println("4 查看学生");
            System.out.println("5 退出");

            System.out.println("请输入你的选择：");
            Scanner sc = new Scanner(System.in);

            String line = sc.nextLine();
            switch (line){
                case "1":
                    addStudent(arrayList);
                    break;
                case "2":
                    deleteStudent(arrayList);
                    break;
                case "3":
                    updateStudent(arrayList);
                    break;
                case "4":
                    showAllStudent(arrayList);
                    break;
                case "5":
                    System.exit(0); //JVM退出
                default:
                    System.out.println("输入错误");
                    break;
            }
        }
    }

    public static boolean isUsed(ArrayList<Student> arrayList, String sid){
        boolean flag = false;

        for (int i=0; i<arrayList.size(); i++){
            Student s = arrayList.get(i);
            if(s.getSid().equals(sid)){
                flag = true;
                break;
            }
        }

        return flag;
    }

    /*public static void addStudent(ArrayList<Student> arrayList){
        Scanner sc = new Scanner(System.in);

        System.out.println("请输入学生学号：");
        String sid = sc.nextLine();
        System.out.println("请输入学生姓名：");
        String name = sc.nextLine();
        System.out.println("请输入学生年龄：");
        String age = sc.nextLine();
        System.out.println("请输入学生地址：");
        String address = sc.nextLine();

        Student s = new Student();
        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 void addStudent(ArrayList<Student> arrayList){
        Scanner sc = new Scanner(System.in);

        String sid;
        while (true){
            System.out.println("请输入学生学号：");
            sid = sc.nextLine();

            boolean flag = isUsed(arrayList, sid);
            if(flag){
                System.out.println("该学号已存在");
            }else {
                break;
            }
        }
        System.out.println("请输入学生姓名：");
        String name = sc.nextLine();
        System.out.println("请输入学生年龄：");
        String age = sc.nextLine();
        System.out.println("请输入学生地址：");
        String address = sc.nextLine();

        Student s = new Student();
        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 void showAllStudent(ArrayList<Student> arrayList){
        if(arrayList.size() == 0){
            System.out.println("暂无记录");
            return;
        }

        System.out.println("学号\t\t姓名\t\t年龄\t\t地址");
        for (int i=0; i<arrayList.size(); i++){
            Student s = arrayList.get(i);
            System.out.println(s.getSid() + "\t\t" + s.getName() + "\t\t" + s.getAge() + "\t\t" + s.getAddress());
        }
    }

    /*public static void deleteStudent(ArrayList<Student> arrayList){
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入待删除学生的学号：");
        String sid = sc.nextLine();

        for (int i=0; i<arrayList.size(); i++){
            Student s = arrayList.get(i);
            if(s.getSid().equals(sid)){
                arrayList.remove(i);
                break;
            }
        }

        System.out.println("删除成功");
    }*/

    public static void deleteStudent(ArrayList<Student> arrayList){
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入待删除学生的学号：");
        String sid = sc.nextLine();

        int index = -1;
        for (int i=0; i<arrayList.size(); i++){
            Student s = arrayList.get(i);
            if(s.getSid().equals(sid)){
                index = i;
                break;
            }
        }

        if(index == -1){
            System.out.println("该信息不存在");
        }else {
            arrayList.remove(index);
            System.out.println("删除成功");
        }
    }

    /*public static void updateStudent(ArrayList<Student> arrayList){
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入待修改学生的学号：");
        String sid = sc.nextLine();

        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("请输入地址：");
        String address = sc.nextLine();

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

        for (int i=0; i<arrayList.size(); i++){
            Student ss = arrayList.get(i);
            if(ss.getSid().equals(sid)){
                arrayList.set(i, s);
                break;
            }
        }

        System.out.println("修改成功");
    }*/

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

        int index = -1;
        for (int i=0; i<arrayList.size(); i++){
            Student s = arrayList.get(i);
            if(s.getSid().equals(sid)){
                index = i;
                break;
            }
        }

        if(index == -1){
            System.out.println("该信息不存在");
        }else {
            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("请输入地址：");
            String address = sc.nextLine();

            Student student = new Student();
            student.setSid(sid);
            student.setName(name);
            student.setAge(age);
            student.setAddress(address);

            arrayList.set(index, student);
            System.out.println("修改成功");
        }
    }

}