尝试读取文本文件并将其转换为具有不同原语的对象

Question

我正在尝试编写一种方法，使用阅读器从普通的txt文件（学生ID-学生姓名 - 学生姓氏）中读取学生详细信息，并创建并返回相应的新学生对象。 。 txt文件包含逐行的详细信息。学生ID在一条线上，名字将在下一行。

我试图在方法readStudent（）中这样做

class StudentInputStream{

BufferedReader in;
public StudentInputStream(InputStream input) {
        in = new BufferedReader(new InputStreamReader(input));
    }

@Override
    public void close() throws IOException {
        in.close();
    }

    public Student readStudent() throws IOException {
        /*Student student1 = new student();*/
        return null; 
    }
}

Answer 1

代码不言自明，如果您有任何疑问，请告诉我。

File file = new File("Your file's path");
     Scanner sc=null;
     try {
        sc = new Scanner(file);
     } catch (FileNotFoundException e) {
        e.printStackTrace();
     }
     ArrayList<Student> list = new ArrayList<>();
     while(sc.hasNextLine()){
         if(sc.nextLine().equalsIgnoreCase("student")){
             //Assuming each property is in the seperate line of file
         String id,name,surname=null;
         if(sc.hasNextLine()){
         id = sc.nextLine();
         /*if id is int use
          * int id = Integer.parseInt(sc.nextLine());
          */
         }
         if(sc.hasNextLine()){
             name = sc.nextLine();
         }
         if(sc.hasNextLine()){
             surname = sc.nextLine();
         }
         list.add(new Student(id,name,surname));

         }
     }

使用bufferedReader：

InputStream in = new FileInputStream("Your file's path");
     BufferedReader br = new BufferedReader(new InputStreamReader(in));
     String str;
     ArrayList<Student> list = new ArrayList<>();
     while((str=br.readLine())!=null){
         if(str.equalsIgnoreCase("student")){
             String id=null,name=null,surname=null;
             if((str=br.readLine())!=null){
             id = str;
             /*if id is int use
              * int id = Integer.parseInt(sc.nextLine());
              */
             }
             if((str=br.readLine())!=null){
                 name = str;
             }
             if((str=br.readLine())!=null){
                 surname = str;
             }
             list.add(new Student(id,name,surname));
         }
     }

使用ObjectInputStream

OutputStream out = new FileOutputStream("yourfilepath.bin");
     ObjectOutputStream outputStream = new ObjectOutputStream(out);

     Student s1 = new Student("100383", "JOHN", "MITCHELL");
     Student s2 = new Student("100346", "AMY", "CHING");


     outputStream.writeObject(s1);
     outputStream.writeObject(s2);
     outputStream.writeObject(null);//to realize that you reach the end of file

     outputStream.close();
     out.close();

     InputStream in = new FileInputStream("yourfilepath.bin");
     ObjectInputStream inputStream = new ObjectInputStream(in);

     Student temp = null;

     while((temp =(Student)inputStream.readObject())!=null){
         System.out.println(temp.id+","+temp.name+","+temp.surname);
     }

OUTPUT

100383，JOHN，MITCHELL

100346，AMY，CHING