Question

这是我代码的一部分。基本上，我试图将double Avg和char gradeLetter中的值存储在doubleAVG和charGRADE数组中。到目前为止，我得到的是在第一个循环中，假设Avg = 2，那么它将被存储在文件中，但是如果存在第二个循环，并且Avg的值更改为3，那么3将被保存在文件中两次。它将删除2并将数字3保存两次。我该如何解决？我希望第一个循环存储可以设置为2的Avg的第一个值，然后在第二个循环中存储可以设置为3的平均Avg的新值，但不覆盖2。忽略注释。

    try {
        FileWriter fw = new FileWriter(fileN);

        for (int count = 0; count < students; count++) {

            doubleAVG = new double[students];
            charGRADE = new char[students];

            doubleAVG[count] = Avg;
            charGRADE[count] = gradeLetter;

            fw.write("This is the grade of: " + FirstName + " " + LastName
                    + " ");
            fw.write(String.valueOf(doubleAVG[count]) + " ");
            fw.write(charGRADE[count]);
        }
        fw.close();
    } catch (Exception e) {
        System.out.println(e);
    }

Answer 1

请为此修改您的代码：

public class Main {

    public static void main(String[] args) {
        try {
            FileWriter fw = new FileWriter(new File("F://test.txt"));
            Scanner sc = new Scanner(System.in);
            int students = 2;
            double[] doubleAVG = new double[students];
            char[] charGRADE = new char[students];
            double avg = 0.0;
            char gradeLetter;
            String FirstName = "";
            String LastName = "";
            for (int count = 0; count < students; count++) {
                System.out.println("Enter average :");
                avg = sc.nextDouble();
                System.out.println("Enter grade :");
                gradeLetter = sc.next().charAt(0);
                System.out.println("Enter First Name :");
                FirstName = sc.next();
                System.out.println("Enter Last Name :");
                LastName = sc.next();
                doubleAVG[count] = avg;
                charGRADE[count] = gradeLetter;
                fw.write("This is the grade of: " + FirstName + " " + LastName + " ");
                fw.write(String.valueOf(doubleAVG[count]) + " ");
                fw.write(charGRADE[count] + System.lineSeparator());
            }
            fw.close();
            sc.close();
        } catch (Exception e) {
            System.out.println(e);
        }

    }

}

控制台输入：

Enter average :
70.45
Enter grade :
B
Enter First Name :
John 
Enter Last Name :
Johnson
Enter average :
90.47
Enter grade :
A
Enter First Name :
Michael 
Enter Last Name :
Jordan

在 test.txt 中：

This is the grade of: John Johnson 70.45 B
This is the grade of: Michael Jordan 90.47 A

Answer 2

您是否知道java Serialize方法，该方法将创建类文件及其对象中具有的所有数据结构的xml文件，使其中的嵌套结构看起来像特定时间点的对象一样原始XML？这可能是由于在5种确切的本机数据类型上中继了Java，而对象只是这些数据类型的集合。看看上面带有Stackoverflow答案链接的评论，我只是向您介绍了该机制。

如何将值存储在数组中并将其保存在文件中

2 个答案: