Question

这是我的问题。

    (f)Define a method, public String toString(),  that returns a String consisting of the Student object’s admin number, name and average score.

    (h)Define another constructor with the method signature Student(String studentRecord),where studentRecord is of the format given below:   adminNo;name;day/month/year;test1;test2;test3 birthdate
       Example of a given string: 031234F;Michael Tan;01/08/1980;60;70;98

    (i)Break up studentRecord into its constituent elements and use them to initialise the class variables, adminNo, name, birthdate, test1, test2, test3.

    (i) Define a main() method to read a single record from the "student.txt" and **display the admin number, name and average score of the student.**

这是我的代码：

    public class Student {

String adminNo;
String name;
GregorianCalendar birthDate;
int test1,test2,test3;

public Student(String adminNo,String name,String birthDate,int test1, int test2, int test3){
    this.adminNo = adminNo;
    this.name = name;
    this.birthDate = MyCalendar.convertDate(birthDate);
    this.test1 = test1;
    this.test2 = test2;
    this.test3 = test3;
}

public Student(String studentRecord){
    Scanner sc = new Scanner(studentRecord);
    sc.useDelimiter(";");
    adminNo = sc.next();
    name = sc.next();
    birthDate = MyCalendar.convertDate(birthDate.toString());
    test1 = sc.nextInt();
    test2 = sc.nextInt();
    test3 = sc.nextInt();
}

public int getAverage(){ 
    return (( test1 + test2 + test3 ) / 3 ) ;
}

public String toString(){
    return (adminNo + " " + name + " " + getAverage());
}

public static void main(String [] args){
    Student s = new Student ("121212A", "Tan Ah Bee", "12/12/92", 67, 72, 79);
    System.out.println(s);

    String fileName = "student.txt";
    try{
        FileReader fr = new FileReader(fileName);
        Scanner sc = new Scanner(fr);

        while(sc.hasNextLine()){
            System.out.println(sc.nextLine());
        }

        fr.close();
    }catch(FileNotFoundException exception){
        System.out.println("File " + fileName + " was not found");
    }catch(IOException exception){
        System.out.println(exception);
    }
}

这是info int text file的格式：

    031234F;Michael Tan;01/08/1980;60;70;98

我设法打印出来：

    121212A Tan Ah Bee 72
    031234F;Michael Tan;01/08/1980;60;70;98
    123456J;Abby;12/12/1994;67;78;89

但这就是问题所在：

    121212A Tan Ah Bee 72
    031234F Michael Tan 72
    123456J Abby 72

我错过了什么吗？我只知道这是toString（）方法，但我不知道如何将它放在while循环中。

任何帮助将不胜感激。提前谢谢。

Answer 1

你有：

while(sc.hasNextLine()){
    System.out.println(sc.nextLine());
}

您似乎需要：

    while(sc.hasNextLine()){
        Student stu = new Student(sc.nextLine());
        System.out.println(stu.toString());
    }

上面的代码将为类Student调用构造函数，它将拆分该行并填充其字段。然后你的toString（）方法将创建一个指定格式的输出字符串。

ReadFile和Split信息

1 个答案: