学生管理系统(上)

第一个小项目:学生管理系统(上)
1.添加学生
2.删除学生
3.修改学生
4.查询学生

package com.itheima;import java.util.ArrayList;
import java.util.Scanner;
public class Student2 {public static void startStudent2() {ArrayList<Student1> list =new ArrayList<>();loop:while (true) {System.out.println("-----------欢迎来到黑马学生系统-------------");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:查询学生");System.out.println("5:退出");System.out.println("请输入你的选择");Scanner sc = new Scanner(System.in);String choose = sc.next();switch(choose){case "1":addStudent(list);break;case "2":deleteStudent(list);break;case "3":updataStudent(list);break;case "4":queryStudent(list);break;case "5":System.out.println("退出");break loop;default:System.out.println("没有这个选项");}}}public static void addStudent(ArrayList<Student1> list){Student1 s = new Student1();Scanner sc = new Scanner(System.in);while (true) {System.out.println("请输入学生的id");String id = sc.next();boolean flag = contains(list, id);if(flag){System.out.println("id已经存在,请重新录入");}else{s.setId(id);break;}}System.out.println("请输入学生的姓名");String name = sc.next();s.setName(name);System.out.println("请输入学生的年龄");int age = sc.nextInt();s.setAge(age);System.out.println("请输入学生的地址");String address = sc.next();s.setAddress(address);list.add(s);System.out.println("学生信息添加成功");}public static void deleteStudent(ArrayList<Student1> list){Scanner sc = new Scanner(System.in);System.out.println("请输入要删除的id");String id = sc.next();int index = getIndex(list,id);if(index>=0){list.remove(index);System.out.println("id为:"+id+"的学生删除成功");}else{System.out.println("id不存在,删除失败");}}public static void updataStudent(ArrayList<Student1> list){Scanner sc = new Scanner(System.in);System.out.println("请输入要修改学生的信息");String id = sc.next();int index = getIndex(list,id);if(index == -1){System.out.println("要修改的id"+id+"不存在,请重新输入");return;}Student1 stu = list.get(index);System.out.println("请输入要修改学生姓名");String newName = sc.next();stu.setName(newName);System.out.println("请输入要修改的学生年龄");int newAge = sc.nextInt();stu.setAge(newAge);System.out.println("请输入要修改的学生家庭住址");String newAddress = sc.next();stu.setAddress(newAddress);System.out.println("学生信息修改成功");}public static void queryStudent(ArrayList<Student1> list){if(list.size()==0){System.out.println("当前无学生信息,请添加后再查询");return;}System.out.println("id\t\t姓名\t年龄\t家庭住址");for (int i = 0; i < list.size(); i++) {Student1 stu = list.get(i);System.out.println(stu.getId()+"\t"+stu.getName()+"\t"+stu.getAge()+"\t"+stu.getAddress());}}public static boolean contains(ArrayList<Student1> list, String id){for (int i = 0; i < list.size(); i++) {Student1 stu = list.get(i);String sid = stu.getId();if(sid.equals(id)){return true;}}return false;}public static int getIndex(ArrayList<Student1>list,String id){for (int i = 0; i < list.size(); i++) {Student1 stu = list.get(i);String sid = stu.getId();if(sid.equals(id)){return i;}}return -1;}
}

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