Java项目：学生管理系统（HashSet）

项目要求

能够实现以下四种需求：

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

代码展示

main类：

package com.zzu.test;

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

import com.zzu.vo.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("请输入学生id");
				String id = scanner.next();
				System.out.println("请输入学生name");
				String name = scanner.next();
				System.out.println("请输入学生mobile");
				String mobile = scanner.next();
				System.out.println("请输入学生address");
				String address = scanner.next();
				Student student = new Student();
				student.setId(id);
				if(set.contains(student)) {
					System.out.println("该学生学号重复，请重新输入");
					return ;
				}
				student.setName(name);
				student.setMobile(mobile);
				student.setAddress(address);
				set.add(student);
				System.out.println("添加成功");
				System.out.println("*****"+set.size());
				break;
			}
	       
			case 2:{
				Student student = new Student();
				System.out.println("请输入学生id");
				String id = scanner.next();
				student.setId(id);
				if(set.remove(student)) {//判断是否删除成功
					System.out.println("删除成功");
					return;
				}
				System.out.println("删除失败");
				break;
			}
	        

			case 3:{
				Student student = new Student();
				System.out.println("请输入学生id");
				String id = scanner.next();
				student.setId(id);
				if(!set.contains(student)) {
					System.out.println("学号为："+id+"的学生不存在！修改失败");
					return;
				}
				for(Student stu : set) {//stu是需要修改学生的地址
					if(stu.getId().equals(id)) {
						System.out.println("请输入学生新name");
						String name = scanner.next();
						System.out.println("请输入学生新mobile");
						String mobile = scanner.next();
						System.out.println("请输入学生新address");
						String address = scanner.next();
						stu.setName(name);
						stu.setMobile(mobile);
						stu.setAddress(address);
						System.out.println("修改成功");
						return;
					}
				}
				break;
			}
				
			case 4:{
				Student student = new Student();
				System.out.println("请输入学生学号");
				String id = scanner.next();
				student.setId(id);
				if(!set.contains(student)) {
					System.out.println("我找到学号为："+id+"的学生！");
					return ;
				}
				for(Student stu : set) {
					if(stu.getId().equals(id)) {
						System.out.println(stu);
						return;
					}
				}
				break;
			}
			default:
				System.out.println("I'm Sorry,there is not the "+option+" option,please try again.");
		}
	}
}
           

Student类：

package com.zzu.vo;

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 int hashCode() {
		// TODO Auto-generated method stub
		return id.hashCode();
	}
	@Override//equals
	public boolean equals(Object obj) {//this代表正在试图保存的对象；obj是HashSet集合中保存的数据
		if(obj instanceof Student) {
			Student stu = (Student)obj;
			//return this.id.equals(stu.id);
			return stu.id.equals(this.id);
		}
		return false;
	}
	
	@Override
	public String toString() {
		return "Student [id=" + id + ", name=" + name + ", mobile=" + mobile + ", address=" + address + "]";
	}
}