用HashSet模拟实现学生信息管理系统中的增删改查

我会带着你远行 2022-05-15 00:24 219阅读 0赞

**任务需求：**  
用HashSet模拟实现学生信息管理系统中的增删改查。  
往HashSet集合中存入自定对象时，姓名和年龄相同为同一个人，  
属于重复元素，不能加入。  
**所需知识点：**  
1.Set接口的实现类HashSet；  
**代码如下：**

***Student.java:***

package cn.demo.student;
    
    public class Student {
    	private String name ; 
    	private int age ;
    	public Student() {
    		super();
    		// TODO Auto-generated constructor stub
    	}
    	public Student(String name, int age) {
    		super();
    		this.name = name;
    		this.age = age;
    	}
    	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;
    	}
    	@Override
    	public int hashCode() {
    		final int prime = 31;
    		int result = 1;
    		result = prime * result + age;
    		result = prime * result + ((name == null) ? 0 : name.hashCode());
    		return result;
    	}
    	@Override
    	public boolean equals(Object obj) {
    		if (this == obj)
    			return true;
    		if (obj == null)
    			return false;
    		if (getClass() != obj.getClass())
    			return false;
    		Student other = (Student) obj;
    		if (age != other.age)
    			return false;
    		if (name == null) {
    			if (other.name != null)
    				return false;
    		} else if (!name.equals(other.name))
    			return false;
    		return true;
    	}
    	@Override
    	public String toString() {
    		return "Student [name=" + name + ", age=" + age + "]";
    	} 
    }

***Main.java:***

package cn.demo.main;
    
    import java.util.HashSet;
    import java.util.Scanner;
    
    import cn.demo.student.Student;
    
    public class Main {
    
    	public static void main(String[] args) {
    
    			Demo();
    	}
    
    	private static void Demo() {
    		HashSet<Student> hs = new HashSet<>() ;
    		int newFlag = 0 ;
    		while(newFlag==0){
    		Show();
    		Scanner scr = new Scanner(System.in);
    		int number = scr.nextInt() ; 
    		if(number==1){
    			ADD(hs, scr);
    		}else if(number==2){
    			Remove(hs, scr);
    		}else if(number==3){
    			Amend(hs, scr);
    		}else if(number==4){
    			Refer(hs);
    		}else{
    			System.out.println("退出！");
    			newFlag = 1 ; 
    		}
    }
    	}
    
    	private static void Refer(HashSet<Student> hs) {
    		System.out.println();
    		System.out.println("--------查询学生信息--------");
    		System.out.println("所有学生信息如下：");
    		System.out.println("姓名        年龄");
    		for (Student student : hs) {
    			System.out.println(student.getName()+"        "+student.getAge());
    		}
    	}
    
    	private static void Amend(HashSet<Student> hs, Scanner scr) {
    		System.out.println();
    		System.out.println("--------修改学生信息--------");
    		System.out.println("请输入所要修改学生的名字："); 
    		String newName = scr.next() ;
    		int flag = 0 ; 
    		for(Student stu : hs){
    			if(newName.equals(stu.getName())){
    				System.out.println("输入修改的新名字：");
    				String newName1 = scr.next() ;
    				System.out.println("输入修改的新年龄：");
    				int newAge1 = scr.nextInt() ;
    				stu.setName(newName1);
    				stu.setAge(newAge1);
    				System.out.println("修改成功!");
    				flag = 1 ; 
    				break ; 
    			}
    		}
    		if(flag==0){
    			System.out.println("没有此人！");
    		}
    	}
    
    	private static void Remove(HashSet<Student> hs, Scanner scr) {
    		System.out.println();
    		System.out.println("--------删除学生信息--------");
    		System.out.println("请输入所要删除学生的名字："); 
    		String newName = scr.next() ;
    		int flag = 0 ; 
    		for(Student stu : hs){
    			if(newName.equals(stu.getName())){
    				hs.remove(stu);
    				System.out.println("删除成功！");
    				flag = 1 ; 
    				break ; 
    			}
    		}
    		if(flag==0){
    			System.out.println("没有此人！");
    		}
    	}
    
    	private static void ADD(HashSet<Student> hs, Scanner scr) {
    		System.out.println();
    		System.out.println("--------添加学生信息--------");
    		System.out.println("添加学生信息的数量为：");
    		int n = scr.nextInt() ; 
    		for(int i=0;i<n;i++){
    			System.out.println("学生的姓名为：");
    			String name = scr.next() ; 
    			System.out.println("学生的年龄为：");
    			int age = scr.nextInt() ; 
    			hs.add(new Student(name,age));
    		}
    	}
    
    	private static void Show() {
    		System.out.println("--------学生管理系统--------");
    		System.out.println("          1.增加");
    		System.out.println("          2.删除");
    		System.out.println("          3.修改");
    		System.out.println("          4.查询");
    		System.out.println("          5.退出");
    		System.out.println("请输入您的选择：");
    	}
    
    }