创建Student类

public class Student{

	private int id;
	private String name;
	private int age;
	private String gender;
	
	public Student() {
		super();
	}

	public Student(String gender) {
		this.gender=gender;
	}

	public int getId() {
		return id;
	}


	public void setId(int 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 getGender() {
		return gender;
	}


	public void setGender(String gender) {
		this.gender = gender;
	}


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


	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", age=" + age + ", gender=" + gender + "]";
	}	
}

创建StudentManager类

public class StudentManger {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		// 创建学生对象集合
		ArrayList<Student> students = new ArrayList<Student>();
		// 管理界面
		while (true) {
			System.out.println("---------欢迎来到学生管理界面---------");
			System.out.println("-----------1.查看学生信息------------");
			System.out.println("-----------2.增加学生信息------------");
			System.out.println("-----------3.修改学生信息------------");
			System.out.println("-----------4.删除学生信息------------");
			System.out.println("-----------5.退出系统---------------");
			System.out.println("请输入功能编号：");
			int num = scanner.nextInt();
			if (num == 5) {
				System.out.println("谢谢使用，即将退出系统！");
				return;
			}
			switch (num) {
			case 1:
				read(students);
				break;
			case 2:
				add(students);
				break;
			case 3:
				update(students);
				break;
			case 4:
				delete(students);
				break;
			default:
				System.out.println("输入有误！");
				break;
			}
		}
	}

	// 删除
	public static void delete(ArrayList<Student> students) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("-----------4.删除学生信息------------");
		System.out.println("-----------请输入要删除的学生的学号：------------");
		int id = scanner.nextInt();
		boolean findId = false;
		for (int i = 0; i < students.size(); i++) {
			if (students.get(i).getId() == id) {
				findId = true;
				students.remove(i);
				System.out.println("删除成功！");
			}
		}
		if (!findId) {
			System.out.println("要删除的学生不存在！");
		}

	}

	// 修改
	public static void update(ArrayList<Student> students) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("-----------3.修改学生信息------------");
		System.out.println("-----------请输入要修改的学生的学号：------------");
		int id2 = scanner.nextInt();
		boolean findId = false;
		for (int i = 0; i < students.size(); i++) {
			if (students.get(i).getId() == id2) {
				findId = true;
				System.out.println("请输入学生的新的name: ");
				scanner.nextLine();
				String name = scanner.nextLine();
				System.out.println("请输入学生的新的gender: ");
				// scanner.nextLine();
				String gender = scanner.nextLine();
				System.out.println("请输入学生的新的age: ");
				int age = scanner.nextInt();
				students.get(i).setName(name);
				students.get(i).setGender(gender);
				students.get(i).setAge(age);
				System.out.println("修改成功！");
			}
		}
		if (!findId) {
			System.out.println("要修改的学生不存在！");
		}
	}

	// 添加
	public static void add(ArrayList<Student> students) {
		Scanner scanner = new Scanner(System.in);
		while (true) {
			System.out.println("-----------2.增加学生信息------------");
			System.out.println("请输入学生的id: ");
			int id = scanner.nextInt();
			System.out.println("请输入学生的name: ");
			// scanner.nextLine();
			String name = scanner.next();
			System.out.println("请输入学生的gender: ");
			// scanner.nextLine();
			String gender = scanner.next();
			System.out.println("请输入学生的age: ");
			int age = scanner.nextInt();
			Student student = new Student(id, name, age, gender);
			students.add(student);
			System.out.println("是否要继续输入：1.继续 2.退出");
			int num = scanner.nextInt();
			if (num == 2) {
				System.out.println("退出成功！");
				break;
			} else if (num == 1) {
				continue;
			} else {
				System.out.println("输入有误！");
			}
		}
	}

	// 查看
	public static void read(ArrayList<Student> students) {
		System.out.println("-----------1.查看学生信息------------");
		if (students.isEmpty()) {
			System.out.println("你要查看的信息不存在！");
		} else {
			for (Student student : students) {
				System.out.println(student);
			}
		}
	}
}