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java - 尝试读取 txt 文件并将它们转换为具有不同原语的对象

问题描述

我正在尝试编写一种方法，该方法使用阅读器从纯 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 文件逐行包含详细信息。学生证在一行，名字在下一行。

我试图在方法 readStudent() 中做到这一点

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; 
    }
}

标签： javainputstreambufferedreader

解决方案

代码是不言自明的，如果您有任何问题，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));
         
         }
     }

使用缓冲读取器：

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);
     }

输出

100383，约翰，米切尔

100346,艾米,清

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