java练习:定义一个学生类 Student,包含属性name, age, id，性别，创高跑步公里数distance。设置每个属性的getter/setter方法，定义一个班级类，包含属性班级名称，学院等属性，班级的所有学生都存储在里面（49人)。-把班级班级成员写入要一个txt文件中，每个学生占一行,每个属性逗号分割。例如:姓名:张三,学号:111,...姓名:李四,学号:112,...-从txt文件重新读取然后把班级成员写入要一个csv文件中(Excel)

好的，下面是Java代码实现：

Student类：

public class Student {
    private String name;
    private int age;
    private String id;
    private String gender;
    private int distance;

    public Student(String name, int age, String id, String gender, int distance) {
        this.name = name;
        this.age = age;
        this.id = id;
        this.gender = gender;
        this.distance = distance;
    }

    // getter/setter methods
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getDistance() {
        return distance;
    }

    public void setDistance(int distance) {
        this.distance = distance;
    }
}

Class类：

import java.io.*;

public class Class {
    private String className;
    private String college;
    private Student[] students;

    public Class(String className, String college) {
        this.className = className;
        this.college = college;
        this.students = new Student[49];
    }

    // getter/setter methods
    public String getClassName() {
        return className;
    }

    public void setClassName(String className) {
        this.className = className;
    }

    public String getCollege() {
        return college;
    }

    public void setCollege(String college) {
        this.college = college;
    }

    public Student[] getStudents() {
        return students;
    }

    public void setStudents(Student[] students) {
        this.students = students;
    }

    // write students to txt file
    public void writeStudentsToFile(String fileName) throws IOException {
        FileWriter fileWriter = new FileWriter(fileName);
        PrintWriter printWriter = new PrintWriter(fileWriter);

        for (int i = 0; i < students.length; i++) {
            Student student = students[i];
            String line = "姓名:" + student.getName() + ",学号:" + student.getId() + ",年龄:" + student.getAge() + ",性别:" + student.getGender() + ",跑步公里数:" + student.getDistance();
            printWriter.println(line);
        }

        printWriter.close();
        fileWriter.close();

        System.out.println("班级成员已写入文件" + fileName);
    }

    // read students from txt file and write to csv file
    public void readStudentsFromFile(String txtFileName, String csvFileName) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new FileReader(txtFileName));
        FileWriter fileWriter = new FileWriter(csvFileName);
        PrintWriter printWriter = new PrintWriter(fileWriter);

        String line = bufferedReader.readLine();
        while (line != null) {
            String[] parts = line.split(",");
            String name = parts[0].split(":")[1];
            String id = parts[1].split(":")[1];
            int age = Integer.parseInt(parts[2].split(":")[1]);
            String gender = parts[3].split(":")[1];
            int distance = Integer.parseInt(parts[4].split(":")[1]);

            Student student = new Student(name, age, id, gender, distance);
            students[students.length - 1] = student;

            // write to csv file
            printWriter.print(name + ",");
            printWriter.print(age + ",");
            printWriter.print(id + ",");
            printWriter.print(gender + ",");
            printWriter.println(distance);

            line = bufferedReader.readLine();
        }

        printWriter.close();
        fileWriter.close();
        bufferedReader.close();

        System.out.println("班级成员已从文件" + txtFileName + "中读取并写入文件" + csvFileName);
    }
}

使用示例：

public class Main {
    public static void main(String[] args) throws IOException {
        Class cls = new Class("计算机科学与技术1班", "计算机学院");

        // create 49 students
        for (int i = 0; i < 49; i++) {
            Student student = new Student("张三" + i, 20 + i % 5, "2021000" + String.format("%02d", i + 1), i % 2 == 0 ? "男" : "女", i * 100);
            cls.getStudents()[i] = student;
        }

        // write to txt file
        cls.writeStudentsToFile("students.txt");

        // read from txt file and write to csv file
        cls.readStudentsFromFile("students.txt", "students.csv");
    }
}

运行后会在项目目录下生成students.txt和students.csv两个文件，分别是文本和CSV格式的班级成员信息。