Java实现学生管理系统(HashSet)

功能：

1、添加学生信息
2、删除学生信息
3、修改学生信息
4、查询学生信息

代码：

Main:

package HashMian;

import java.util.HashSet;
import java.util.Scanner;

import Hashvo.Student;



public class Main {
	
	private static HashSet<Student> set = new HashSet<Student>();
	public static void main(String[] args) {
		System.out.println("*********************************");
		System.out.println("*\t\t\t\t*");
		System.out.println("*\t欢迎使用学生信息管理系统\t*");
		System.out.println("*\t\t\t\t*");
		System.out.println("*********************************");
		while (true) {
			menu();
		}
	}
	
	static void menu() {
		System.out.println("1、添加学生信息");
		System.out.println("2、删除学生信息");
		System.out.println("3、修改学生信息");//地址传递
		System.out.println("4、查询学生信息");//name
		System.out.println("请输入操作，以Enter键结束:");
		Scanner scanner = new Scanner(System.in);
		int option  = scanner.nextInt();
		switch (option) {
			case 1:{
				System.out.println("请输入学号：");
				Student student = new Student();
				String id = scanner.next();
				student.setId(id);
/*				for(Student stu : set) {
					if(id.equals(stu.getId())) {
						System.out.println("添加失败");
						return;
					}
				}*/
				if(set.contains(student)) {//必须重写equals方法
					System.out.println("学号不允许重复，添加失败");
					return;
				}
				System.out.println("请输入姓名：");
				String name = scanner.next();
				student.setId(name);
				System.out.println("请输入手机号：");
				String mobile = scanner.next();
				student.setId(mobile);
				System.out.println("请输入地址：");
				String address = scanner.next();
				student.setId(address);
				set.add(student);
				System.out.println(set.size());
				System.out.println("添加成功");
				break;
			}
			case 2:{
				System.out.println("请输入学号：");
				Student student = new Student();
				String id = scanner.next();
				student.setId(id);
				if(set.remove(student)) {//先判断集合中是否含有该元素，再进行删除
		    		System.out.println("删除成功");
		    	}else {
		    		System.out.println("删除失败");
		    	}
				
				break;
			}
			case 3:{
				System.out.println("请输入学号：");
				Student student = new Student();
				String id = scanner.next();
				student.setId(id);
				if(!set.contains(student)) {
					System.out.println("没有找到此学号");
					return;
				}
				for(Student stu : set) {
					if(id.equals(stu.getId())) {
						System.out.println("请输入正确姓名：");
						String name = scanner.next();
						stu.setId(name);
						System.out.println("请输入正确手机号：");
						String mobile = scanner.next();
						stu.setId(mobile);
						System.out.println("请输入正确地址：");
						String address = scanner.next();
						stu.setId(address);
						System.out.println("修改成功");
						return;
					}
				}
				break;
			}
			case 4:{
				System.out.println("请输入学号：");
				Student student = new Student();
				String id = scanner.next();
				student.setId(id);
				if(!set.contains(student)) {
					System.out.println("没有找到此学号");
					return;
				}
				for(Student stu : set) {
					if(id.equals(stu.getId())) {
						System.out.println(stu);
						return;
					}
				}
				break;
			}
			default:
				System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");
		}
	}
}

Student:

package Hashvo;

public class Student {

	private String id;
	private String name;
	private String mobile;
	private String address;
	
	public String getId() {
		return id;
	}
	public void setId(String id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getMobile() {
		return mobile;
	}
	public void setMobile(String mobile) {
		this.mobile = mobile;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}

	@Override
	public boolean equals(Object obj) {
		if(obj instanceof Student) {
			Student student = (Student) obj;
			return student.id.equals(this.id);
		}
		return false;
	}
	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", mobile=" + mobile + ", address=" + address + "]";
	}
	@Override
	public int hashCode() {
		return id.hashCode();
	}
}