如何从Java中的用户输入中读取并将其写入文件 [英] How to read from user's input in Java and write it to a file
问题描述
我想创建一个简单的独立应用程序,它将接受用户的一些输入(一些数字和数学函数 f(x,y...))并将它们写入文件.然后在这个文件的帮助下,我将运行一个命令.
I want to create a simple stand-alone application that will take some input from user (some numbers and mathematical functions f(x,y...)) and write them to a file. Then with the help of this file I will run a command.
我需要的基本成分:
-- 用于用户输入的 JTextArea.
-- JTextArea for users input.
-- ButtonHandler/ActionListener 并将输入写入 (txt) 文件
-- ButtonHandler/ActionListener and writing of the input to a (txt) file
-- ButtonHandler/ActionLister 执行命令
-- ButtonHandler/ActionLister to execute a command
最好的方法是什么?
我拥有的当前正在运行的代码(基本上是一个玩具)——它不写任何东西,只是执行——是:
A current running code that I have (basically a toy) - which does not write anything, just executes - is:
import java.applet.*;
import java.lang.*;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.Dialog;
import java.io.IOException;
import java.io.InputStream;
import java.io.*;
import java.util.*;
import java.io.BufferedWriter;
public class Runcommand3
{
public static void main(String[] args) throws FileNotFoundException, IOException
{
//JApplet applet = new JApplet();
//applet.init();
final JFrame frame = new JFrame("Change Backlight");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(null);
frame.add(panel);
JButton button = new JButton("Click me to Run");
button.setBounds(55,100,160,30);
panel.add(button);
frame.setSize(260,180);
frame.setVisible(true);
//This is an Action Listener which reacts to clicking on the button
button.addActionListener(new ButtonHandler());
}
}
class ButtonHandler implements ActionListener{
public void actionPerformed(ActionEvent event){
double value = Double.parseDouble(
JOptionPane.showInputDialog("please enter backlight value"));
//File theFile = new File("thisfile.txt");
//theFile.write(value);
String command = "xbacklight -set " + value;
try{Runtime run = Runtime.getRuntime();
Process pr = run.exec(command);}
catch(IOException t){t.printStackTrace();}
}
}
在上面的示例中,如何将值"写入文件?那么,如何添加更多输入(更多文本字段)?我可以在同一个班级做还是我需要更多?我的困惑来自(主要但不仅限于)在 ButtonHandler 类内部我不能定义任何其他对象(即打开和写入文件等).
In the above example how can I write 'value' to a file? Then, how can I add more input (more textfields)? Can I do it in the same class or I need more? My confusion comes (mainly but not only) from the fact that inside the ButtonHandler class I can NOT define any other objects (ie, open and write files etc).
推荐答案
这是我写入文件的方式.我会让你把这段代码转换成你的 GUI 来练习.查看更多关于 BufferedWriter 和 FileWriter
This is the way I would write to a file. I will let you convert this code into your GUI for practice. See more on BufferedWriter and FileWriter
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.Scanner;
public class Files {
public static void main(String args[]){
System.out.print("Enter Text: ");
Scanner scan = new Scanner(System.in);
String text = scan.nextLine();
FileWriter fWriter = null;
BufferedWriter writer = null;
try {
fWriter = new FileWriter("text.txt");
writer = new BufferedWriter(fWriter);
writer.write(text);
writer.newLine();
writer.close();
System.err.println("Your input of " + text.length() + " characters was saved.");
} catch (Exception e) {
System.out.println("Error!");
}
}
}
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