자바 단순 학생 관리 시스템(집합 작성 사용)

package com.dong.studentmanager;

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;
    }
    //get/set  
    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;
    }
}

package com.dong.studentmanager;

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

public class StudentManager {
    public static void main(String[] args) {
        //      
        ArrayList<Student> arrayList = new ArrayList<>();
        //       
        while (true) {
            System.out.println("--------          --------");
            System.out.println("1     ");
            System.out.println("2     ");
            System.out.println("3     ");
            System.out.println("4     ");
            System.out.println("5   ");
            System.out.println("       :");
            // Scanner        
            Scanner scanner = new Scanner(System.in);
            String line = scanner.nextLine();
            // switch         
            switch (line) {
                case "1":
                    System.out.println("--------    --------");
                    addStudent(arrayList);
                    break;
                case "2":
                    System.out.println("--------    --------");
                    updateStudent(arrayList);
                    break;
                case "3":
                    System.out.println("--------      --------");
                    findStudent(arrayList);
                    break;
                case "4":
                    System.out.println("--------    --------");
                    deleteStudent(arrayList);
                    break;
                case "5":
                    System.out.println("    ！！！");
                    System.exit(0);//JVM  
                default:
                    System.out.println("       ！！！");
            }
        }
    }

    //      
    public static void addStudent(ArrayList<Student> arrayList) {
        //           
        Scanner scanner = new Scanner(System.in);
        //   sid while       ，       sid
        String sid;
        while (true) {
            System.out.println("       :");
            sid = scanner.nextLine();
            boolean flag = isUsed(arrayList, sid);
            if (flag) {
                System.out.println("           ，     ！");
            } else {
                break;
            }
        }
        System.out.println("       :");
        String name = scanner.nextLine();
        System.out.println("       :");
        String age = scanner.nextLine();
        System.out.println("       :");
        String address = scanner.nextLine();
        //      ，                 
        Student s = new Student();
        s.setSid(sid);
        s.setName(name);
        s.setAge(age);
        s.setAddress(address);
        //          
        arrayList.add(s);
        //        
        System.out.println("      ");

    }

    //         
    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 updateStudent(ArrayList<Student> arrayList) {
//               
        Scanner scanner = new Scanner(System.in);
        System.out.println("            ：");
        String sid = scanner.nextLine();

        //          
        if (arrayList.size() == 0) {
            System.out.println("   ，         ！");
        } else {
            for (int i = 0; i < arrayList.size(); i++) {
                Student s1 = arrayList.get(i);
                if (s1.getSid().equals(sid)) {
                    //         
                    System.out.println("       ：");
                    String name = scanner.nextLine();
                    System.out.println("       ：");
                    String age = scanner.nextLine();
                    System.out.println("       ：");
                    String address = scanner.nextLine();
                    //      
                    Student s = new Student();
                    s.setSid(sid);
                    s.setName(name);
                    s.setAge(age);
                    s.setAddress(address);
                    arrayList.set(i, s);
                    System.out.println("        ！");
                } else {
                    System.out.println("    ,       ");
                }
            }
        }
    }

    //      
    public static void findStudent(ArrayList<Student> arrayList) {
        //          
        if (arrayList.size() == 0) {
            System.out.println("   ，         ！");
        } else {
            System.out.println("  \t  \t  \t   ");
            //  for   （             ）
            for (Student s : arrayList) {
                System.out.println(s.getSid() + "\t\t" + s.getName() + "\t" + s.getAge() + " \t" + s.getAddress());
            }
        }
    }

    //      
    public static void deleteStudent(ArrayList<Student> arrayList) {
        //            
        Scanner scanner = new Scanner(System.in);
        System.out.println("            ");
        String sid = scanner.nextLine();
        //    ，             

        if (arrayList.size() == 0) {
            System.out.println("   ，          ！");
        } else {
            for (int i = 0; i < arrayList.size(); i++) {
                Student s = arrayList.get(i);
                if (s.getSid().equals(sid)) {
                    arrayList.remove(i);
                    System.out.println("      ！");
                } else {
                    System.out.println("      ，      ！");
                }
            }
        }
    }
}

--------          --------
1     
2     
3     
4     
5   
       :