java - 如何拆分具有字符串和双精度的输入文本文件？

Question

我要从 .txt 输入中读取并按行排序到数组中（读取：名字、姓氏、等级 1、等级 2、等级 3），但我遇到了问题。我假设我必须为每个人创建数组，但我无法通过对每个行条目进行排序。我了解如何使用拆分的基础知识，但我假设我必须使用嵌套的 for 循环将字符串与双精度数分开，并将每个字符串放在自己的数组中。我不确定如何编译它。

Answer 1

您可以使用 FileReader 逐行读取。然后，您可以在逗号上拆分结果字符串，并使用 Double.valueOf 来获取您的值。以下示例很简单，但假定文件格式正确：

public class Test {

    static class Student {
        private String firstName;
        private String lastName;
        private double math;
        private double english;
        private double computerScience;

        public Student(String firstName, String lastName, double math,
                double english, double computerScience) {
            this.firstName = firstName;
            this.lastName = lastName;
            this.math = math;
            this.english = english;
            this.computerScience = computerScience;
        }

        @Override
        public String toString() {
            return "Name: " + firstName + " " + lastName + ", Math: " + math +
            ", English: " + english + ", Computer Science: " + computerScience;
        }
    }

    public static void main(String[] args) {
        BufferedReader reader;
        try {
            reader = new BufferedReader(new FileReader("/home/username/grades.txt"));
            String line = reader.readLine();
            while (line != null) {
                String[] gradeArray = line.split(",");
                Student myStudent = new Student(gradeArray[0], gradeArray[1],
                        Double.valueOf(gradeArray[2]), Double.valueOf(gradeArray[3]),
                        Double.valueOf(gradeArray[4]));

                System.out.println(myStudent.toString());
                line = reader.readLine();
            }
        }
        catch (NumberFormatException|IndexOutOfBoundsException badFile) {
            System.out.println("You have a malformed gradebook");
            badFile.printStackTrace();
        }
        catch (IOException e) {
            e.printStackTrace();
        }
    }

}