java - 将数组对象存储到 CSV 文件中，并使用 GUI 的特定参数读取它们

Question

作为作业的一部分，我必须将数组的对象存储在平面文件中，并在满足某些条件时检索它们。我可以很好地保存对象，但在检索它们时，我遇到了获取多个值的问题，我明白出了什么问题，但我正在努力寻找解决方案。这是正在发生的事情的概念。

按钮 10,A(代码中的 R1S10)是我的测试按钮，当我单击它时，它会创建一个事件，我将在下面显示。

按钮 10A 的点击事件 -

private void R1S10ActionPerformed(java.awt.event.ActionEvent evt) {                                      

    seats.add(seat1);


    if (R1S10.getBackground().equals(Color.red) &&(IsSeatBooked().equals("true"))){
        Component frame = null;
        JOptionPane.showMessageDialog(frame, "Seat UnBooked");
        seat1.setBooked("false");
        seat1.setName("");
        R1S10.setBackground(Color.yellow);
        try {
               reader();
            writer();

            //String booked = "true";
            //Pass String booked into csv file
        } catch (IOException ex) {
            Logger.getLogger(SeatingPlan.class.getName()).log(Level.SEVERE, null, ex);
        }

    } 
    else{
        Component frame = null;
        String name = JOptionPane.showInputDialog(frame, "Please enter name of Customer booking");
        if (name.isEmpty()) {
            JOptionPane.showMessageDialog(frame, "No value entered");

        } else if (name != null) {
            seat1.setName(name);
            seat1.setBooked("true");
            R1S10.setBackground(Color.red);
            JOptionPane.showMessageDialog(frame, "Your Booking has been placed");
            try {
                writer();
                reader();
                //String booked = "true";
                //Pass String booked into csv file
            } catch (IOException ex) {
                Logger.getLogger(SeatingPlan.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

}    

接下来是下面的屏幕 -
结果 -

当再次按下按钮时 -

我在此 SeatingPlan.java 中使用三种方法 - writer()、reader() 和 IsSeatBooked()。

座位安排 -

public class SeatingPlan extends javax.swing.JFrame {

/**
 * Creates new form SeatingPlan
 */
String seatNo, name, bookedSeat;
FileWriter fileWriter = null;
List<Seat> seats = new ArrayList<Seat>();


//Seat Object Declaration

Seat seat1 = new Seat("R1S10","","false");
Seat seat2 = new Seat("R1S9", "", "false");
String fileName = "seat.csv";

作者-

 public void writer() throws IOException {
    //Delimiter used in CSV file
    final String NEW_LINE_SEPARATOR = "\n", COMMA_DELIMITER = ",";

    //CSV file header
    final String FILE_HEADER = "seatID,name,booked";

    //fileName = System.getProperty("user.home") + "/seat.csv";
    try {
        fileWriter = new FileWriter(fileName);

        //Write the CSV file header
        fileWriter.append(FILE_HEADER.toString());

        //Add a new line separator after the header
        fileWriter.append(NEW_LINE_SEPARATOR);

        //Write a new student object list to the CSV file
        for (Seat seat : seats) {
            fileWriter.append(String.valueOf(seat.getSeatID()));
            fileWriter.append(COMMA_DELIMITER);
            fileWriter.append(seat.getName());
            fileWriter.append(COMMA_DELIMITER);
            fileWriter.append(seat.isBooked());
            fileWriter.append(NEW_LINE_SEPARATOR);
        }

        System.out.println("CSV file was created successfully !!!");

    } catch (Exception e) {
        System.out.println("Error in CsvFileWriter !!!");
        e.printStackTrace();
    } finally {

        fileWriter.flush();
        fileWriter.close();

    }
}

读者 -

public void reader() {
    //Delimiter used in CSV file
    final String COMMA_DELIMITER = ",";
    //Student attributes index
    final int SEAT_ID_IDX = 0;
    final int SEAT_NAME_IDX = 1;
    final int SEAT_BOOKED = 2;
    //private static final int STUDENT_LNAME_IDX = 2;
    BufferedReader fileReader = null;

    try {

        //Create a new list of student to be filled by CSV file data 
        List<Seat> seats = new ArrayList<>();

        String line = "";

        //Create the file reader
        fileReader = new BufferedReader(new FileReader(fileName));

        //Read the CSV file header to skip it
        fileReader.readLine();

        //Read the file line by line starting from the second line
        while ((line = fileReader.readLine()) != null) {
            //Get all tokens available in line
            String[] tokens = line.split(COMMA_DELIMITER);
            if (tokens.length > 0) {
                //Create a new seat object and fill his  data
                Seat seat = new Seat(tokens[SEAT_ID_IDX],           
                tokens[SEAT_NAME_IDX], tokens[SEAT_BOOKED]);
                seats.add(seat);
                seatNo = tokens[SEAT_ID_IDX];
               //System.out.println("Seat Number: " + seatNo);
                bookedSeat = tokens[SEAT_BOOKED];
              }
        }

        //Print the new student list
        for (Seat seat : seats) {
            System.out.println(seat.toString());
        }
    } catch (Exception e) {
        System.out.println("Error in CsvFileReader !!!");
        e.printStackTrace();
    } finally {
        try {
            fileReader.close();
        } catch (IOException e) {
            System.out.println("Error while closing fileReader !!!");
            e.printStackTrace();
        }
    }

}//end reader

SeatingPlan - 如果我尝试让参数控制结果，但在选择多个座位时 IsBooked 会发生冲突。

 public SeatingPlan() throws IOException {
    setVisible(true);
    initComponents();
    //reader();
    ColourSectionGold();
    ColourSectionBronze();
    reader();

    if(R1S10.getBackground().equals(Color.yellow) && (IsSeatBooked().equals("true"))){ R1S10.setBackground(Color.red);}
    //if(R1S9.getBackground().equals(Color.yellow) && (IsSeatBooked().equals("true2"))){ R1S9.setBackground(Color.red);}
   }

已预订座位 -

 public String IsSeatBooked(){
 return bookedSeat;   
}//end IsSeatBooked 

我使用上面的方法作为参数来查看座位是否已预订，但是当单击新座位时，它会设置“bookedSeat”的整个值 - 这使得系统无法正常工作。我知道代码效率不是很高，但是如果我解释正确的话，是否有针对此问题的临时解决方案。

此外，我还将包括我的座位类(class) -

public class Seat {
private String seatID;
private String booked;
private String name;
private int price;

public Seat(String seatID,String name,String booked){
    this.seatID = seatID;
    this.booked = "";
    this.name = name;
    this.price = price;
}

public String getSeatID() {
    return seatID;
}

public void setSeatID(String seatID) {
    this.seatID = seatID;
}

public String isBooked() {
    return booked;
}

public void setBooked(String booked) {
   this.booked = booked;
}

public String getStatus(){
    return booked;
}

public String getName() {
    return name;
}

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

public void setPrice() {
   this.price = price;
}}//end class Seat 

查看创建的 CSV 文件 -

我希望能够单击多个按钮并保存其状态，按钮 10 目前工作正常，但由于 IsBooked 一次只有一个值，因此会发生冲突。

如果您花时间查看此内容，我将不胜感激。任何建设性的批评都是有帮助的，任何想法都会很棒!

谢谢，稻田。

Answer 1

代码太多，无法准确了解您在做什么。

您可以创建一个 Properties 文件，而不是使用 csv 文件。 Properties文件将以以下形式存储数据:

key:data

因此，在您的情况下，键将是 id:A1、A2...，数据将是预订座位的人的姓名。

所以文件一开始是空的。创建 GUI 时，您将创建一个循环来检查每个 id 以查看是否在“属性”字段中找到条目。如果找到，则显示已占用的座位，否则该座位为空。

然后，每当您想预订座位时，只需使用 setProperty(...) 方法即可。

Properties 类具有 load(...) 和 store(...) 方法。

因此，Properties 类允许您以最少的努力轻松管理平面文件数据库。

请注意，您永远不会有像 R1S10 这样的变量名称。这将需要 100 个带有 if/else 语句的不同变量。相反，您可以扩展 JButton 并将行和座位作为参数传递给按钮。然后，在按钮的 ActionListener 中，您可以访问行/座位信息来构建用作属性文件键的 ID。

编辑:

Couldn't quite make the loop that checks if the ID is in the properties file.

如果属性为 null，则海底为空。

import java.util.*;

public class Main
{
    public static void main(String[] args)
    {
        Properties properties = new Properties();
        properties.setProperty("A2", "Smith");
        properties.setProperty("C3", "Jones");

        String[] rows = { "A", "B", "C", "D" };
        int seats = 4;

        for (int row = 0; row < rows.length; row++)
        {
            for (int seat = 1; seat <= seats; seat++)
            {
                String key = rows[row] + seat;
                String property = properties.getProperty( key );

                System.out.println(key + " : " + property);
            }
        }


    }
}