java案例 java案例教程

Java编程基础：实现一个简单的学生管理系统

在这篇文章中，我们将通过一个简单的Java案例来学习如何实现一个学生管理系统，这个系统将包括添加学生、删除学生、修改学生信息和查询学生信息等功能，我们将使用Java的面向对象编程（OOP）特性来实现这个系统。

我们需要创建一个学生类（Student），用于存储学生的基本信息，在这个类中，我们将定义学生的姓名、学号和年龄等属性，并为这些属性提供相应的getter和setter方法，我们还需要重写toString方法，以便在输出学生信息时能够显示更友好的格式。

public class Student {
    private String name;
    private String id;
    private int age;
    public Student(String name, String id, int age) {
        this.name = name;
        this.id = id;
        this.age = age;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
    @Override
    public String toString() {
        return "Student{" +
                "name='" + name + '\'' +
                ", id='" + id + '\'' +
                ", age=" + age +
                '}';
    }
}

接下来，我们需要创建一个学生管理类（StudentManager），用于实现学生管理系统的功能，在这个类中，我们将使用一个ArrayList来存储学生对象，并提供添加、删除、修改和查询学生的方法，为了方便用户操作，我们还将提供一个菜单界面，让用户可以选择执行相应的操作。

import java.util.ArrayList;
import java.util.Scanner;
public class StudentManager {
    private ArrayList<Student> students = new ArrayList<>();
    public void addStudent(Student student) {
        students.add(student);
    }
    public void deleteStudent(String id) {
        for (Student student : students) {
            if (student.getId().equals(id)) {
                students.remove(student);
                break;
            }
        }
    }
    public void updateStudent(String id, String name, int age) {
        for (Student student : students) {
            if (student.getId().equals(id)) {
                student.setName(name);
                student.setAge(age);
                break;
            }
        }
    }
    public Student findStudent(String id) {
        for (Student student : students) {
            if (student.getId().equals(id)) {
                return student;
            }
        }
        return null;
    }
}

我们需要编写一个主程序（Main），用于接收用户的输入并调用学生管理类的方法，在这个程序中，我们将使用一个循环来不断接收用户的输入，直到用户选择退出系统，我们还需要使用一个Scanner对象来读取用户的输入。

import java.util.Scanner;
import java.util.InputMismatchException;
import java.util.List;
import java.util.ArrayList;
import java.util.stream.Collectors;
import java.util.stream.StreamSupport;
import java.io.FileInputStream;
import java.io.ObjectInputStream;
import java.io.FileOutputStream;
import java.io.ObjectOutputStream;
import java.io.IOException;
import java.io.Serializable;
import java.util.Comparator;
import java.util.Collections;
import java.util.OptionalInt;
import java.util.stream.IntStream;
import java.util.stream.Stream;
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