如何在Java Eclipse中讀取Excel CSV文件（逗號分隔值）？

Question

目標：創建一個面向對象的圖形Java應用程序，該程序將執行以下操作：讀取CSV（逗號分隔值）文件，該文件由學生姓名（名字，姓氏），ID和內容和交付的初始標記（對於-1使用-1值）組成未評估的學生。

這是我的代碼，但是當我單擊“選擇文件”時。當它確實應該打開文件並讀取數據時，它顯示“ Expected firstName，lastName，ID，Content and Delivery”。 但由於某種原因，它無法正常工作。 在此處輸入圖片說明

下面是我的代碼：

私有類ChooseFileListener實現ActionListener {

public void actionPerformed(ActionEvent event) {
  Section<Student> section;

  JFileChooser fileChooser = new JFileChooser();
  FileNameExtensionFilter filter = new FileNameExtensionFilter(
                                                               "CSV file", "csv");
  fileChooser.setFileFilter(filter);
  int returnValue = fileChooser.showOpenDialog(null);
  if (returnValue == JFileChooser.APPROVE_OPTION) {
    File selectedFile = fileChooser.getSelectedFile();
    if (selectedFile != null) {
      section = createNewSection(selectedFile);
      loadStudents(section, selectedFile);
      System.out.print(selectedFile);
}
}
}
}

public void RandomStudent(){
ArrayList<Student> students = new ArrayList<>();
max = (students.size()-1);
int x = (int) Math.random()* students.size();
System.out.println(x);
}


private Section<Student> createNewSection(File selectedFile) {
String filename = selectedFile.getName();
Section<Student> section = new Section<Student>(filename);
return section;
}


private void loadStudents(Section<Student> section, File selectedFile) {
Scanner in;
int MAX_COMMAS = 5;
try {
  in = new Scanner(selectedFile);
  String line = "";
  String[] studentData;
  in.nextLine();
  while (in.hasNext()) {
    line = in.nextLine();
    studentData = line.split(",");
    if (studentData.length == MAX_COMMAS) {
      section.addStudent(new Student(studentData[0],studentData[1],
                                     Integer.valueOf(studentData[2]), 
                                     Integer.valueOf(studentData[3]),
                                     Integer.valueOf(studentData[4])));
    } else {
      throw new Exception(
                          "Invalid file format. \nExcepted: firstname, lastname, id, content, delivery");
    }
  }
} catch (Exception e) {
  JOptionPane.showMessageDialog(null, e.getMessage());
}
}
}

我現在已經創建了另一個名為Section的類：

包裹patel.Jainam;

導入java.util.ArrayList;

公共課第{

 private String data;
 private String FirstName;
 private String LastName;
 private int studentID;
 private int ContentMark;
 private int DeliveryMark;

 private ArrayList<Student> students = new ArrayList<>();

 public void FileData(String First, String Last, int ID, int Content, int Delivery){
      this.FirstName = First;
      this.LastName = Last;
      this.studentID = ID;
      this.ContentMark = Content;
      this.DeliveryMark = Delivery;
     }

public String setFirst(String First){
      return First;
}

 public String setLast (String Last){
     return Last;
 }
 public int setstudentID (int ID) {
     return ID;
 }
 public int setContentMark (int Content) {
     return Content;
 }
 public int setDeliveryMark (int Delivery) {
     return Delivery;
 }   

 public Section(String data) {
  this.data = data;
 }

 public void addStudent(Student student) {
  students.add(student);
 }

}

Answer 1

問題是您檢查了MAX_COMMAS ，但是您正在根據字段數來檢查它。 對於格式正確的文件，此值將始終為5。 因此，您可以確保到達代碼的其他部分並始終拋出。

您想要表達的是：

if (studentData.length != MAX_COMMAS)