关于#java#的问题：把创建的学生对象录入文件，在需要对信息进行操作时

Question

把创建的学生对象录入文件，在需要对信息进行操作时，读取数据。怎么进行修改啊？

用io的file

package managementSystem;
import java.util.ArrayList;
import java.util.Scanner;
public class system {
     public static void main(String[] args) {
            ArrayList<Student> list = new ArrayList<>();
            //创建学生对象
            Student s1 = new Student("202201","李一","男","数据科学与大数据技术","一班","401","2004.1","重庆");
            Student s2 = new Student("202202","李二","男","数据科学与大数据技术","一班","401","2004.4","重庆");
            Student s3 = new Student("202203","李三","男","数据科学与大数据技术","一班","401","2004.7","重庆");
            Student s4 = new Student("202204","李四","男","数据科学与大数据技术","二班","402","2004.7","重庆");
            Student s5 = new Student("202205","李五","女","数据科学与大数据技术","二班","402","2003.9","重庆");
            Student s6 = new Student("202206","李六","男","数据科学与大数据技术","二班","402","2004.5","重庆");
            Student s7 = new Student("202207","李七","女","计算机科学与技术","一班","403","2004.4","重庆");
            Student s8 = new Student("202208","李八","男","计算机科学与技术","一班","403","2004.3","重庆");
            Student s9 = new Student("202209","李九","男","计算机科学与技术","一班","403","2003.1","重庆");
            Student s10 = new Student("202210","李十","男","计算机科学与技术","二班","404","2004.2","重庆");
            Student s11 = new Student("202211","李十一","女","计算机科学与技术","二班","404","2004.3","重庆");
            Student s12= new Student("202212","李十二","女","计算机科学与技术","二班","404","2003.5","重庆");
            Student s13 = new Student("202213","李十三","女","计算机科学与技术","三班","405","2004.6","重庆");
            Student s14 = new Student("202214","李十四","女","计算机科学与技术","三班","405","2004.1","重庆");
            Student s15 = new Student("202215","李十五","女","计算机科学与技术","三班","405","2004.8","重庆");
            //把学生添加到集合
            list .add(s1);
            list .add(s2);
            list .add(s3);
            list .add(s4);
            list .add(s5);
            list .add(s6);
            list .add(s7);
            list .add(s8);
            list .add(s9);
            list .add(s10);
            list .add(s11);
            list .add(s12);
            list .add(s13);
            list .add(s14);
            list .add(s15);
            start:
            while (true) {
                System.out.println("-----------------欢迎来到学生管理系统-------------------");
                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");
                System.out.println("4:按专业班级查询学生信息");
                System.out.println("5:按学号查询学生信息");
                System.out.println("6:显示所有学生信息");
                System.out.println("7:退出");
                System.out.println("请输入您的选择：");
                Scanner sc = new Scanner(System.in);
                String choose = sc.next();
                switch (choose) {
                case "1":
                    Add.addStudent(list);
                    break;
                case "2":
                    Delete.deleteStudent(list);
                    break;
                case "3":
                    break;
                case "4":
                    ccSearch.ccSearchStudent(list);
                    break;
                case "5":
                    idSearch.viewStudent(list);
                    break;   
                case "6":
                    View.viewStudent(list);
                    break;
                case "7":
                {
                    System.out.println("退出");
                    break start;
                }
                default:
                    System.out.println("没有这个选项，请重新输入");
                }
            }
     }
}

Answer 1

不知道你这个问题是否已经解决, 如果还没有解决的话:

• 帮你找了个相似的问题, 你可以看下: https://ask.csdn.net/questions/7673223
• 这篇博客你也可以参考下：使用file把文件读取到浏览器并用进度条显示
• 以下回答来自chatgpt:

  针对您的问题，您需要使用Java的IO流将创建的学生对象录入到文件中，并且能够在需要对其信息进行操作时进行读取，同时还需要实现对文件中数据的修改操作。

  具体步骤如下：

  1. 创建一个Student类，包含各种学生属性的定义（姓名、学号、年龄等等），并且实现Serializable接口，以便在写入文件时可以顺利进行对象序列化，代码如下：

  import java.io.Serializable;
  
  public class Student implements Serializable{
      private String name;
      private int id;
      private int age;
  
      public Student(String name, int id, int age) {
          this.name = name;
          this.id = id;
          this.age = age;
      }
  
      public String getName() {
          return name;
      }
  
      public int getId() {
          return id;
      }
  
      public int getAge() {
          return age;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public void setId(int id) {
          this.id = id;
      }
  
      public void setAge(int age) {
          this.age = age;
      }   
  }
  

  1. 创建一个操作文件的类，用于存储、读取以及修改学生对象数据。首先，需要使用File类创建一个指向文件的对象，然后使用ObjectOutputStream将学生对象写入文件中。

  import java.io.*;
  
  public class StudentFile {
      private File file;
  
      public StudentFile(String filePath) {
          file = new File(filePath);
      }
  
      public void save(Student student) {
          try {
              ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(file));
              out.writeObject(student);
              out.close();
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  
      public Student load() {
          try {
              ObjectInputStream in = new ObjectInputStream(new FileInputStream(file));
              Student student = (Student) in.readObject();
              in.close();
              return student;
          } catch (IOException | ClassNotFoundException e) {
              e.printStackTrace();
          }
          return null;
      }
  
      public void update(Student newStudent) {
          try {
              Student oldStudent = load();
              ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream(file));
              out.writeObject(newStudent);
              out.close();
          } catch (IOException e) {
              e.printStackTrace();
          }
      }
  }
  

  1. 在主函数中进行测试。首先是创建一个学生对象，并通过StudentFile的save方法将这个对象存储到文件中。然后，再通过StudentFile的load方法读取存储在文件中的学生对象，测试读取是否成功。最后，调用StudentFile的update方法进行学生对象数据的修改测试。

  public class Main {
      public static void main(String[] args) {
          // 创建学生对象并存储到文件
          Student student1 = new Student("张三", 1001, 20);
          StudentFile fileHelper = new StudentFile("D://Student.txt");
          fileHelper.save(student1);
  
          // 从文件中读取学生对象
          Student student2 = fileHelper.load();
          System.out.println("学生姓名：" + student2.getName());
          System.out.println("学生学号：" + student2.getId());
          System.out.println("学生年龄：" + student2.getAge());
  
          // 修改学生对象数据
          Student student3 = new Student("李四", 1002, 22);
          fileHelper.update(student3);
          Student student4 = fileHelper.load();
          System.out.println("修改后学生姓名：" + student4.getName());
          System.out.println("修改后学生学号：" + student4.getId());
          System.out.println("修改后学生年龄：" + student4.getAge());
      }
  }
  

  以上就是一种基于Java IO流实现将学生对象写入文件并进行读取和修改的解决方案。

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