java - 当我按下按钮时，如何将 stringbuilder 的结果打印到 jtext 区域

Question

我有这段代码，我想知道如何打印//System.out.println(result);当我按下按钮时进入 jtext 区域。

我尝试使用text.settext(result);尝试使用 text.settext(result.toString());

我没主意了

package nioCount;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JButton;

import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Component;
public class Settings 
{






public static void main(String...args) throws IOException {

    String line = null;
    Pattern category = Pattern.compile("^\\[(.*?)\\]$"); // matches [Cars]
    Pattern itemAndQuantity = Pattern.compile("^(\\w+)=(\\d+)$"); // matches Lamborghini=6
    StringBuilder result = new StringBuilder();
    {


    try (BufferedReader br = new BufferedReader(new FileReader("D:/test.txt"))) {
        while ((line = br.readLine()) != null) {
            Matcher categoryMatcher = category.matcher(line);
            Matcher itemMatcher = itemAndQuantity.matcher(line);
            if (categoryMatcher.matches()) {
                if (result.length() > 0) { // found new category, put on new line
                    result.append(System.getProperty("line.separator"));
                }
                String categoryName = categoryMatcher.group(1); // Cars
                result.append(categoryName).append(": "); // Cars: 
            } else if (itemMatcher.matches()) {
                String item = itemMatcher.group(1); // Lamborghini
                String quantity = itemMatcher.group(2); // 6
                result.append(item).append(" ") // Lamborghini
                      .append(quantity) // Lamborghini 6
                      .append(", "); // Lamborghini 6,
            }
        }


        // we are done processing the file, output the result
        //System.out.println(result);


        }
        JTextArea text;
        text = new JTextArea(result.toString());

        JFrame frame = new JFrame();
        frame.setForeground(Color.YELLOW);
        frame.setAutoRequestFocus(false);


        //text.setAlignmentX(Component.LEFT_ALIGNMENT);
       // text.setHorizontalAlignment(SwingConstants.CENTER);
        text.setEditable(false);
        text.setBounds(100, 92, 436, 195);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.getContentPane().add(text);
        frame.getContentPane().setPreferredSize(new Dimension(700,500));


        JButton btnNewButton = new JButton("Count");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                Reader in = null;

            }
        });
        btnNewButton.setBounds(100, 385, 134, 50);
        frame.getContentPane().add(btnNewButton);

        JButton btnResetCount = new JButton("Reset Count");
        btnResetCount.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                text.setText(null);

            }
        });
        btnResetCount.setBounds(402, 385, 134, 50);
        frame.getContentPane().add(btnResetCount);
        frame.setResizable(true);
        frame.pack();
        frame.setVisible(true);
        frame.setLocationRelativeTo(null);
    }




}
}

Answer 1

做你想做的事情的最快方法是:

import java.awt.Dimension;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import javax.swing.JFrame;
import javax.swing.JTextArea;
import javax.swing.JButton;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class Settings
{

public static void main(String... args) throws IOException
{
        String result = aMethodThatReadsTheFileAndReturnsAString();

        JTextArea text = new JTextArea(result);

        JFrame frame = new JFrame();
        frame.setForeground(Color.YELLOW);
        frame.setAutoRequestFocus(false);
        text.setEditable(false);
        text.setBounds(100, 92, 436, 195);

        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);
        frame.getContentPane().add(text);
        frame.getContentPane().setPreferredSize(new Dimension(700, 500));

        JButton btnNewButton = new JButton("Count");
        btnNewButton.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent arg0)
                {
                    text.setText(aMethodThatReadsTheFileAndReturnsAString());
                }
            });
        btnNewButton.setBounds(100, 385, 134, 50);
        frame.getContentPane().add(btnNewButton);

        JButton btnResetCount = new JButton("Reset Count");
        btnResetCount.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    text.setText("");

                }
            });
        btnResetCount.setBounds(402, 385, 134, 50);
        frame.getContentPane().add(btnResetCount);
        frame.setResizable(true);
        frame.pack();
        frame.setVisible(true);
        frame.setLocationRelativeTo(null);

}

public static String aMethodThatReadsTheFileAndReturnsAString()
{
    String line = null;
    Pattern category = Pattern.compile("^\\[(.*?)\\]$"); // matches [Cars]
    Pattern itemAndQuantity = Pattern.compile("^(\\w+)=(\\d+)$"); // matches
                                                                    // Lamborghini=6
    StringBuilder result = new StringBuilder("result @"+new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS").format(new Date())+" is: \n");
    {

        try (BufferedReader br = new BufferedReader(new FileReader(
                "D:/test.txt")))
        {
            while ((line = br.readLine()) != null)
            {
                Matcher categoryMatcher = category.matcher(line);
                Matcher itemMatcher = itemAndQuantity.matcher(line);
                if (categoryMatcher.matches())
                {
                    if (result.length() > 0)
                    { // found new category, put on new line
                        result.append(System.getProperty("line.separator"));
                    }
                    String categoryName = categoryMatcher.group(1); // Cars
                    result.append(categoryName).append(": "); // Cars:
                }
                else if (itemMatcher.matches())
                {
                    String item = itemMatcher.group(1); // Lamborghini
                    String quantity = itemMatcher.group(2); // 6
                    result.append(item).append(" ") // Lamborghini
                            .append(quantity) // Lamborghini 6
                            .append(", "); // Lamborghini 6,
                }
            }
        }
        catch(Exception x)
        {
            result.append(x.toString());
        }

        return result.toString();
    }
}
}

或 text.appendText(aMethodThatReadsT​​heFileAndReturnsAString()) 如果您希望将输出添加到 TextArea 中已显示内容的末尾。

正确的方法是按下按钮时开始读取，并在操作后显示结果。读取应该由另一个为此目的启动的线程来完成。您可能想阅读 Concurrency in Swing