Question

关于这个问题： Reading data from CSV file and displaying it in a JTable

我试图调整这个问题的程序，以使其符合我的需要，但它犯了错误。我希望程序显示位于项目根目录中的文件（所以我必须写File DataFile = new File("res.csv");）。问题是它只显示2行，当显示4行时。

以下是代码：

import java.util.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.BorderLayout;
import java.awt.*;
import javax.swing.border.EmptyBorder;
import java.io.*;
import javax.swing.table.*;

public class T1Data extends JPanel {
    private final JTable table;

    public T1Data() {
        super(new BorderLayout(3, 3));

        this.table = new JTable(new MyModel());
        this.table.setPreferredScrollableViewportSize(new Dimension(700, 70));
        this.table.setFillsViewportHeight(true);

        JPanel ButtonOpen = new JPanel(new FlowLayout(FlowLayout.CENTER));
        add(ButtonOpen, BorderLayout.SOUTH);

        // Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);

        // Add the scroll pane to this panel.
        add(scrollPane, BorderLayout.CENTER);

        // add a nice border
        setBorder(new EmptyBorder(5, 5, 5, 5));

        CSVFile Rd = new CSVFile();
        MyModel NewModel = new MyModel();
        this.table.setModel(NewModel);
        File DataFile = new File("res.csv");
        ArrayList<String[]> Rs2 = Rd.ReadCSVfile(DataFile);

        NewModel.AddCSVData(Rs2);
        System.out.println("Rows: " + NewModel.getRowCount());
        System.out.println("Cols: " + NewModel.getColumnCount());

    }

    // Method for reading CSV file
    public class CSVFile {
        private ArrayList<String[]> Rs = new ArrayList<>();
        private String[] OneRow;

        public ArrayList<String[]> ReadCSVfile(File DataFile) {
            try {
                BufferedReader brd = new BufferedReader(
                        new FileReader(DataFile));

                while (brd.readLine() != null) {
                    String st = brd.readLine();
                    OneRow = st.split(",|\\s|;");
                    Rs.add(OneRow);
                    System.out.println(Arrays.toString(OneRow));
                } // end of while
            } // end of try
            catch (Exception e) {
                String errmsg = e.getMessage();
                System.out.println("File not found:" + errmsg);
            } // end of Catch
            return Rs;
        }// end of ReadFile method
    }// end of CSVFile class

    private static void createAndShowGUI() {
        // Create and set up the window.
        JFrame frame = new JFrame("T1Data");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Create and set up the content pane.
        T1Data newContentPane = new T1Data();
        frame.setContentPane(newContentPane);

        // Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    class MyModel extends AbstractTableModel {
        private String[] columnNames = { "1", "2", "3", "4", "5", "6", "7", "8" };
        private ArrayList<String[]> Data = new ArrayList<>();

        public void AddCSVData(ArrayList<String[]> DataIn) {
            this.Data = DataIn;
            this.fireTableDataChanged();
        }

        @Override
        public int getColumnCount() {
            return columnNames.length;// length;
        }

        @Override
        public int getRowCount() {
            return Data.size();
        }

        @Override
        public String getColumnName(int col) {
            return columnNames[col];
        }

        @Override
        public Object getValueAt(int row, int col) {
            return Data.get(row)[col];

        }
    }

    public static void main(String[] args) {
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

CSV文件的内容：带“。”这似乎很麻烦：

Valeur par défaut,07/04/2014,0.5,1,0,0,0
Valeur par défaut,07/04/2014,0.5,1,0,0,0
Valeur par défaut,07/04/2014,0.5,1,0,0,0
Valeur par défaut,07/04/2014,0.5,1,0,0,0
Valeur par défaut,07/04/2014,0.5,1,0,0,0

Answer 1

你做过两次readLine。一旦处于while状态，接下来就在其中。您正在丢失在while条件下读取的行。

<强>更新将代码更改为以下内容，它给出了预期的输出：

package stackoverflow;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.util.ArrayList;
import java.util.Arrays;

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.border.EmptyBorder;
import javax.swing.table.AbstractTableModel;

public class T1Data extends JPanel {
    private final JTable table;

    public T1Data() {
        super(new BorderLayout(3, 3));
        this.table = new JTable(new MyModel());
        this.table.setPreferredScrollableViewportSize(new Dimension(700, 70));
        this.table.setFillsViewportHeight(true);
        JPanel ButtonOpen = new JPanel(new FlowLayout(FlowLayout.CENTER));
        add(ButtonOpen, BorderLayout.SOUTH);
        // Create the scroll pane and add the table to it.
        JScrollPane scrollPane = new JScrollPane(table);
        // Add the scroll pane to this panel.
        add(scrollPane, BorderLayout.CENTER);
        // add a nice border
        setBorder(new EmptyBorder(5, 5, 5, 5));
        CSVFile Rd = new CSVFile();
        MyModel NewModel = new MyModel();
        this.table.setModel(NewModel);
        File DataFile = new File("res.csv");
        ArrayList<String[]> Rs2 = Rd.ReadCSVfile(DataFile);
        NewModel.AddCSVData(Rs2);
        System.out.println("Rows: " + NewModel.getRowCount());
        System.out.println("Cols: " + NewModel.getColumnCount());
    }

    // Method for reading CSV file
    public class CSVFile {
        private final ArrayList<String[]> Rs = new ArrayList<String[]>();
        private String[] OneRow;

        public ArrayList<String[]> ReadCSVfile(File DataFile) {
            try {
                BufferedReader brd = new BufferedReader(new FileReader(DataFile));
                while (brd.ready()) {
                    String st = brd.readLine();
                    OneRow = st.split(",|\\s|;");
                    Rs.add(OneRow);
                    System.out.println(Arrays.toString(OneRow));
                } // end of while
            } // end of try
            catch (Exception e) {
                String errmsg = e.getMessage();
                System.out.println("File not found:" + errmsg);
            } // end of Catch
            return Rs;
        }// end of ReadFile method
    }// end of CSVFile class

    private static void createAndShowGUI() {
        // Create and set up the window.
        JFrame frame = new JFrame("T1Data");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Create and set up the content pane.
        T1Data newContentPane = new T1Data();
        frame.setContentPane(newContentPane);
        // Display the window.
        frame.pack();
        frame.setVisible(true);
    }

    class MyModel extends AbstractTableModel {
        private final String[] columnNames = { "1", "2", "3", "4", "5", "6", "7", "8" };
        private ArrayList<String[]> Data = new ArrayList<String[]>();

        public void AddCSVData(ArrayList<String[]> DataIn) {
            this.Data = DataIn;
            this.fireTableDataChanged();
        }

        @Override
        public int getColumnCount() {
            return columnNames.length;// length;
        }

        @Override
        public int getRowCount() {
            return Data.size();
        }

        @Override
        public String getColumnName(int col) {
            return columnNames[col];
        }

        @Override
        public Object getValueAt(int row, int col) {
            return Data.get(row)[col];
        }
    }

    public static void main(String[] args) {
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                createAndShowGUI();
            }
        });
    }
}

<强>更新

输出： enter image description here

Answer 2

您的问题出在阅读器内的while循环中。你读了一行，测试它是否为空，并且因为它不是，你读取并处理下一行。假设您只看到文件中的第二行和第四行，我是否正确？更好的方法是：

String st = brd.readLine();
while (st != null) {
    <do something>
    st = brd.readLine();
}

OR

while ((String st = brd.readLine()) != null) {
    <do stuff>
}

（通常不鼓励使用第二种变体）

此外，上面的代码充满了不正当行为（不是关闭资源，双模型创建，不一致的命名约定等）。我建议你让某人复习（或发布到https://codereview.stackexchange.com/），除非你知道这些并且只是懒得做出更好的例子。

从特定CSV文件读取数据并将其显示在JTable中

2 个答案: