写数据到.txt文件在JAVA？ [英] Write data to .txt file in JAVA?

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本文介绍了写数据到.txt文件在JAVA？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想知道是否在JAVA中将计算的数据写入文本文件。我的JAVA代码是一个基于GUI的gpa计算器。我只是想添加一个JButton& ActionListener将写入类名称，GPA点数和计算GPA到.txt文件。

这是我的JFrame驱动程序代码：

  import javax.swing.JFrame; 
 
 public class Driver00 
 
 {
 
 public static void main（String [] args）
 
 {
 / * 
 *创建一个框架（外框），并写入文本
 *将作为框架标题显示
 * / 
 JFrame frame = new JFrame（PHILIP MCQUITTY ）; 
 
 //给帧一个大小
 frame.setSize（520，375）; 
 
 //在电脑屏幕上设置位置会出现框架
 frame.setLocation（400，166）; 
 
 //使用这个，所以当你在角落按X时，frame会关闭
 frame.setDefaultCloseOperation（JFrame.EXIT_ON_CLOSE）; 
 
 //将您的面板添加到框架。名称必须匹配Panel类名称
 frame.setContentPane（new GpaCalc（））; 
 
 // frame.setResizable（false）; 
 
 //总是包含
 frame.setVisible（true）; 
 
 
 
 
 $ b $ p $这里是我的JPanel代码：
  import javax.swing。*; 
 import java.awt。*; 
 import java.awt.event。*; 
 
 public class GpaCalc extends JPanel {
 private JLabel GPALabel，c1，c2，c3，c4，c5，c6，c7，g1，g2，g3，g4，g5，g6，g7; 
私人JTextField Class1，Class2，Class3，Class4，Class5，Class6，Class7，Grade1，Grade2，Grade3，Grade4，Grade5，Grade6，Grade7; 
私人双人GPA1，GPA2，GPA3，GPA4，GPA5，GPA6，GPA7，GPA，BigDec; 
 
 public GpaCalc（）{
 setLayout（new FlowLayout（））; 
 
 //类标签
 GPALabel = new JLabel（0.00000000000000）; 
 GPALabel.setFont（new Font（Times New Roman，Font.BOLD，60））; 
 GPALabel.setForeground（Color.red）; 
 
 c1 = new JLabel（Block 1）; 
 c1.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c1.setForeground（Color.black）; 
 
 c2 = new JLabel（Block 2）; 
 c2.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c2.setForeground（Color.black）; 
 
 c3 = new JLabel（Block 3）; 
 c3.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c3.setForeground（Color.black）; 
 
 c4 = new JLabel（Block 4）; 
 c4.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c4.setForeground（Color.black）; 
 
 c5 = new JLabel（Block 5）; 
 c5.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c5.setForeground（Color.black）; 
 
 c6 = new JLabel（Block 6）; 
 c6.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c6.setForeground（Color.black）; 
 
 c7 = new JLabel（Block 7）; 
 c7.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 c7.setForeground（Color.black）; 
 
 //等级标签
 g1 =新的JLabel（GPA Points）; 
 g1.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g1.setForeground（Color.black）; 
 
 g2 = new JLabel（GPA Points）; 
 g2.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g2.setForeground（Color.black）; 
 
 g3 = new JLabel（GPA Points）; 
 g3.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g3.setForeground（Color.black）; 
 
 g4 = new JLabel（GPA Points）; 
 g4.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g4.setForeground（Color.black）; 
 
 g5 = new JLabel（GPA Points）; 
 g5.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g5.setForeground（Color.black）; 
 
 g6 = new JLabel（GPA Points）; 
 g6.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g6.setForeground（Color.black）; 
 
 g7 = new JLabel（GPA Points）; 
 g7.setFont（new Font（Times New Roman，Font.BOLD，20））; 
 g7.setForeground（Color.black）; 
 
 // Class Textfields 
 Class1 = new JTextField（Enter Class Name，10）; 
 Class1.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class2 = new JTextField（Enter Class Name，10）; 
 Class2.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class3 = new JTextField（Enter Class Name，10）; 
 Class3.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class4 = new JTextField（Enter Class Name，10）; 
 Class4.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class5 = new JTextField（Enter Class Name，10）; 
 Class5.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class6 = new JTextField（Enter Class Name，10）; 
 Class6.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Class7 = new JTextField（Enter Class Name，10）; 
 Class7.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 //等级Textfields 
 Grade1 =新的JTextField（0.0，10）; 
 Grade1.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade2 = new JTextField（0.0，10）; 
 Grade2.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade3 = new JTextField（0.0，10）; 
 Grade3.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade4 = new JTextField（0.0，10）; 
 Grade4.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade5 = new JTextField（0.0，10）; 
 Grade5.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade6 = new JTextField（0.0，10）; 
 Grade6.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 Grade7 = new JTextField（0.0，10）; 
 Grade7.setHorizo​​ntalAlignment（SwingConstants.CENTER）; 
 
 // Buttons（s）
 JButton Calculate = new JButton（Calculate）; 
 Calculate.addActionListener（new Listener（））; 
 
 JButton Reset = new JButton（Reset Fields）; 
 Reset.addActionListener（new Listener2（））; 
 
 // Add（s）
 add（GPALabel）; 
 add（c1）; 
 add（Class1）; 
 add（Grade1）; 
 add（g1）; 
 add（c2）; 
 add（Class2）; 
 add（Grade2）; 
 add（g2）; 
 add（c3）; 
 add（Class3）; 
 add（Grade3）; 
 add（g3）; 
 add（c4）; 
 add（Class4）; 
 add（Grade4）; 
 add（g4）; 
 add（c5）; 
 add（Class5）; 
 add（Grade5）; 
 add（g5）; 
 add（c6）; 
 add（Class6）; 
 add（Grade6）; 
 add（g6）; 
 add（c7）; 
 add（Class7）; 
 add（Grade7）; 
 add（g7）; 
 add（Calculate）; 
 add（Reset）; 
 
 
 //动作监听器
 private class监听器实现ActionListener {
 public void actionPerformed（ActionEvent e）{
 
 GPA1 = Double.parseDouble（Grade1.getText（））; 
 GPA2 = Double.parseDouble（Grade2.getText（））; 
 GPA3 = Double.parseDouble（Grade3.getText（））; 
 GPA4 = Double.parseDouble（Grade4.getText（））; 
 GPA5 = Double.parseDouble（Grade5.getText（））; 
 GPA6 = Double.parseDouble（Grade6.getText（））; 
 GPA7 = Double.parseDouble（Grade7.getText（））; 
 
 GPA =（GPA1 + GPA2 + GPA3 + GPA4 + GPA5 + GPA6 + GPA7）/ 7; 
 
 GPALabel.setText（+ GPA）; 
 
 
 
 
 private class Listener2 implements ActionListener {
 public void actionPerformed（ActionEvent e）{
 
 Class1.setText（Enter Class Name）; 
 Class2.setText（Enter Class Name）; 
 Class3.setText（Enter Class Name）; 
 Class4.setText（Enter Class Name）; 
 Class5.setText（Enter Class Name）; 
 Class6.setText（Enter Class Name）; 
 Class7.setText（Enter Class Name）; 
 
 Grade1.setText（0.0）; 
 Grade2.setText（0.0）; 
 Grade3.setText（0.0）; 
 Grade4.setText（0.0）; 
 Grade5.setText（0.0）; 
 Grade6.setText（0.0）; 
 Grade7.setText（0.0）; 
 
 GPALabel.setText（0.00000000000000）; 
 
 
 
 
 
 
 
 
 <解决方案

解决方案检查java I / O api 。下面是将数据写入文件的示例。

  BufferedWriter writer = null; 
 try {
 writer = new BufferedWriter（new FileWriter（./ output.txt））; 
 writer.write（你的数据在这里）; 
} catch（IOException e）{
 System.err.println（e）; 
} finally {
 if（writer！= null）{
 try {
 writer.close（）; 
 catch（IOException e）{
 System.err.println（e）; 
} 
} 
}


I was wondering if it is in JAVA to write the calculated data to a text file. My JAVA code is a GUI based gpa calculator. I just want to add a JButton & ActionListener that will write the Class Name, GPA Points, and calculated GPA to a .txt file.

Here is my JFrame Driver Code:

import javax.swing.JFrame;

public class Driver00

{

  public static void main(String[] args)

  {
    /*
     * Create a frame (outside box) and write what text
     * will be displayed as the frame title
     */
    JFrame frame = new JFrame("PHILIP MCQUITTY");

    // give frame a size
    frame.setSize(520, 375);

    // set location on the computer screen will frame appear
    frame.setLocation(400, 166);

    // use this so when you press X in corner, frame will close
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    // Add your panel to the frame. name must match Panel class name
    frame.setContentPane(new GpaCalc());

    // frame.setResizable(false);

    // always include
    frame.setVisible(true);
  }
}

Here is my JPanel Code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class GpaCalc extends JPanel {
  private JLabel GPALabel, c1, c2, c3, c4, c5, c6, c7, g1, g2, g3, g4, g5, g6, g7;
  private JTextField Class1, Class2, Class3, Class4, Class5, Class6, Class7, Grade1, Grade2, Grade3, Grade4, Grade5, Grade6, Grade7;
  private double GPA1, GPA2, GPA3, GPA4, GPA5, GPA6, GPA7, GPA, BigDec;

  public GpaCalc() {
    setLayout(new FlowLayout());

    // Class Labels
    GPALabel = new JLabel("0.00000000000000");
    GPALabel.setFont(new Font("Times New Roman", Font.BOLD, 60));
    GPALabel.setForeground(Color.red);

    c1 = new JLabel("Block 1");
    c1.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c1.setForeground(Color.black);

    c2 = new JLabel("Block 2");
    c2.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c2.setForeground(Color.black);

    c3 = new JLabel("Block 3");
    c3.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c3.setForeground(Color.black);

    c4 = new JLabel("Block 4");
    c4.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c4.setForeground(Color.black);

    c5 = new JLabel("Block 5");
    c5.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c5.setForeground(Color.black);

    c6 = new JLabel("Block 6");
    c6.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c6.setForeground(Color.black);

    c7 = new JLabel("Block 7");
    c7.setFont(new Font("Times New Roman", Font.BOLD, 20));
    c7.setForeground(Color.black);

    // Grade Labels
    g1 = new JLabel("GPA Points");
    g1.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g1.setForeground(Color.black);

    g2 = new JLabel("GPA Points");
    g2.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g2.setForeground(Color.black);

    g3 = new JLabel("GPA Points");
    g3.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g3.setForeground(Color.black);

    g4 = new JLabel("GPA Points");
    g4.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g4.setForeground(Color.black);

    g5 = new JLabel("GPA Points");
    g5.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g5.setForeground(Color.black);

    g6 = new JLabel("GPA Points");
    g6.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g6.setForeground(Color.black);

    g7 = new JLabel("GPA Points");
    g7.setFont(new Font("Times New Roman", Font.BOLD, 20));
    g7.setForeground(Color.black);

    // Class Textfields
    Class1 = new JTextField("Enter Class Name", 10);
    Class1.setHorizontalAlignment(SwingConstants.CENTER);

    Class2 = new JTextField("Enter Class Name", 10);
    Class2.setHorizontalAlignment(SwingConstants.CENTER);

    Class3 = new JTextField("Enter Class Name", 10);
    Class3.setHorizontalAlignment(SwingConstants.CENTER);

    Class4 = new JTextField("Enter Class Name", 10);
    Class4.setHorizontalAlignment(SwingConstants.CENTER);

    Class5 = new JTextField("Enter Class Name", 10);
    Class5.setHorizontalAlignment(SwingConstants.CENTER);

    Class6 = new JTextField("Enter Class Name", 10);
    Class6.setHorizontalAlignment(SwingConstants.CENTER);

    Class7 = new JTextField("Enter Class Name", 10);
    Class7.setHorizontalAlignment(SwingConstants.CENTER);

    // Grade Textfields
    Grade1 = new JTextField("0.0", 10);
    Grade1.setHorizontalAlignment(SwingConstants.CENTER);

    Grade2 = new JTextField("0.0", 10);
    Grade2.setHorizontalAlignment(SwingConstants.CENTER);

    Grade3 = new JTextField("0.0", 10);
    Grade3.setHorizontalAlignment(SwingConstants.CENTER);

    Grade4 = new JTextField("0.0", 10);
    Grade4.setHorizontalAlignment(SwingConstants.CENTER);

    Grade5 = new JTextField("0.0", 10);
    Grade5.setHorizontalAlignment(SwingConstants.CENTER);

    Grade6 = new JTextField("0.0", 10);
    Grade6.setHorizontalAlignment(SwingConstants.CENTER);

    Grade7 = new JTextField("0.0", 10);
    Grade7.setHorizontalAlignment(SwingConstants.CENTER);

    // Button(s)
    JButton Calculate = new JButton("Calculate");
    Calculate.addActionListener(new Listener());

    JButton Reset = new JButton("Reset Fields");
    Reset.addActionListener(new Listener2());

    // Add(s)
    add(GPALabel);
    add(c1);
    add(Class1);
    add(Grade1);
    add(g1);
    add(c2);
    add(Class2);
    add(Grade2);
    add(g2);
    add(c3);
    add(Class3);
    add(Grade3);
    add(g3);
    add(c4);
    add(Class4);
    add(Grade4);
    add(g4);
    add(c5);
    add(Class5);
    add(Grade5);
    add(g5);
    add(c6);
    add(Class6);
    add(Grade6);
    add(g6);
    add(c7);
    add(Class7);
    add(Grade7);
    add(g7);
    add(Calculate);
    add(Reset);
  }

  // Action Listener(s)
  private class Listener implements ActionListener {
    public void actionPerformed(ActionEvent e) {

      GPA1 = Double.parseDouble(Grade1.getText());
      GPA2 = Double.parseDouble(Grade2.getText());
      GPA3 = Double.parseDouble(Grade3.getText());
      GPA4 = Double.parseDouble(Grade4.getText());
      GPA5 = Double.parseDouble(Grade5.getText());
      GPA6 = Double.parseDouble(Grade6.getText());
      GPA7 = Double.parseDouble(Grade7.getText());

      GPA = (GPA1 + GPA2 + GPA3 + GPA4 + GPA5 + GPA6 + GPA7) / 7;

      GPALabel.setText("" + GPA);

    }

  }

  private class Listener2 implements ActionListener {
    public void actionPerformed(ActionEvent e) {

      Class1.setText("Enter Class Name");
      Class2.setText("Enter Class Name");
      Class3.setText("Enter Class Name");
      Class4.setText("Enter Class Name");
      Class5.setText("Enter Class Name");
      Class6.setText("Enter Class Name");
      Class7.setText("Enter Class Name");

      Grade1.setText("0.0");
      Grade2.setText("0.0");
      Grade3.setText("0.0");
      Grade4.setText("0.0");
      Grade5.setText("0.0");
      Grade6.setText("0.0");
      Grade7.setText("0.0");

      GPALabel.setText("0.00000000000000");

    }

  }

}

解决方案

check java I/O api. Below is an example of writing data to file.

    BufferedWriter writer = null;
    try {
        writer = new BufferedWriter(new FileWriter("./output.txt"));
        writer.write("your data here");
    } catch (IOException e) {
        System.err.println(e);
    } finally {
        if (writer != null) {
            try {
                writer.close();
            } catch (IOException e) {
                System.err.println(e);
            }
        }
    }

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