java只利用方法和数组对数据进行增删改查

最新推荐文章于 2022-08-31 16:53:49 发布

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本文介绍了一个学生信息管理系统的设计与实现，该系统使用Java编程语言，涵盖了学生信息的增删改查功能，通过数组来存储和操作学生数据，实现了基本的数据管理和用户交互。

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package Test8;

public class Student {

int id;
String name;
int age;

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

package Test8;

import java.util.Arrays;
import java.util.Scanner;

public class StudentServer {
Scanner scanner=new Scanner(System.in);
public Student[] Insert(Student[] students,int id,String name,int age){
//增
// System.out.println(students+"–");
Student stu=new Student();
stu.id=id;
stu.name=name;
stu.age=age;
students[students.length-1]=stu;
//System.out.println(Arrays.toString(students));
return students;
}
//扩展数组的长度
public Student[] getNewArray(Student[] students){
Student[] students1=Arrays.copyOf(students, students.length+1);
return students1;

}
//删
public Student[] Del(Student[] students,int id){
	int index=isExist(students, id);
	if(index==-1){
		System.out.println("没有这个人，你输入的信息有误");
	}else {
		students[index]=null;
		students=AfterDel(students);
	}
	return students;
}
//删除信息后，把数组的长度变短
public  Student[] AfterDel(Student[] students){
	Student[] stu=new Student[students.length-1];
	for(int i=0,index1=0;i<students.length;i++,index1++){
		if(students[i]!=null){
			stu[index1]=students[i];
		}else {
			index1--;
			continue;
		}
	}
	return stu;
}
//改
public  void Update(Student[] students,int id){
	//System.out.println(students+"--");
	int index=isExist(students, id);
	//System.out.println("index:"+index);
	if(index==-1){
		System.out.println("没有这个人");
	}else {
		System.out.println("请输入要修改的信息的数字：1-姓名或者2-年龄：");
		int num=scanner.nextInt();
		Student student= students[index];
		selectUpdate(student,num);
	}
}

public void selectUpdate(Student students,int num){
	switch (num) {
	case 1:
		System.out.println("请输入新名字");
		String name = scanner.next();
		students.name = name;
		break;
	case 2:
		System.out.println("请输入新的年龄");
		int age = scanner.nextInt();
		students.age = age;
		break;
	}
	//System.out.println(students+"----");
}
//查
public  void selectAll(Student[] students){
	//System.out.println("----");
	if(students!=null&&students.length>0){
		for(int i=0;i<students.length;i++){
			Student s=students[i];
			System.out.println(s.id+","+s.name+","+s.age);
			//System.out.println(s);
		}
	}else{
		System.out.println("沒有个人");
	}
	
}
//判断是否存在这个人
public  int isExist(Student[] students,int id){
//	System.out.println(students+"---");
	for(int i=0;i<students.length;i++){
		if(students[i].id==id){
			return i;
			
		}
	}
	return -1;
}

}

package Test8;

import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Scanner;
public class TestStudent {
public static Scanner scanner=new Scanner(System.in);
public static void main(String[] args) {

	Student[] students=new Student[0];
	System.out.println(students+"-");
	StudentServer studentServer=new StudentServer();
   // System.out.println();
	
	while(true){
		System.out.println("请执行以下信息：1、添加信息，2、删除信息，3、修改信息，4、查找信息，5、退出");
		int num=scanner.nextInt();
		switch (num) {
		case 1:
			System.out.println("请输入id");
			int id=scanner.nextInt();
			System.out.println("请输入name:");
			String name=scanner.next();
			System.out.println("请输入age:");
			int age=scanner.nextInt();
			//接收students
			students=studentServer.Insert(studentServer.getNewArray(students), id, name, age);
	       System.out.println(students+"+");
			break;
        case 2:
			System.out.println("请输入要删除的对象的id");
			int delId=scanner.nextInt();
			//
			students=studentServer.Del(students, delId);
			break;	
        case 3:
			System.out.println("请输入要修改的用户的id:");
			int sc=scanner.nextInt();
			studentServer.Update(students,sc);
			break;	 
	    case 4:
				studentServer.selectAll(students);
				break;	 
		case 5:
				
					break;	

		default:
			break;
		}
	}
}

}