Java GUI读取具有所述路径的文件

因此，在这个函数中，我想通过输入读取所提到的目录/文件夹中的一些文本文件。用户使用JFILECHOOSER方法选择目录/文件夹，输出将在文本框[目录]中列出。假设fileName是用户输入文件名的文本字段，用户输入文件名后，单击开始按钮。“开始”按钮的功能是查看给定的目录/文件夹[文本框]，搜索文本文件，并使用system.out.printIn输出文本文件的名称。我没有尝试过目录/文件夹路径的代码，因为我不确定如何为其编码。对这个问题有什么帮助或指导吗？我只创建了一个类，而且我对JavaGUI是新手

完整代码如下：

JButton btnStart = new JButton("Start");
        btnStart.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {


                try{                
                    String filename =  fileName.getText();
                    FileReader fr = new FileReader(filename);
                    BufferedReader br = new BufferedReader(fr); 
                    Scanner scan = new Scanner(br);
                     filename = br.readLine();

                    if (filename != null){

                  String text = txtKeyword.getText();  
                  String line;
                  boolean hasError = true;

                while ((line = br.readLine()) != null) {

                if(line.contains(text)){
                    String newline = "\n";
                    jTextArea1.append(line + newline);
                    hasError = false;
                }   
                }
                if (hasError) {

                    JOptionPane.showMessageDialog(null, "Text Not Found");
                       br.close();
                       fr.close();
                    } 
                }}catch(IOException e){
                    JOptionPane.showMessageDialog(null, "File Not Found");
            }   }   
        });

问题1 您仅在尝试打开文件时使用

文件名

值

package com.directory.file;
import java.awt.BorderLayout;
import java.awt.Event;
import java.awt.EventQueue;
import java.awt.TextArea;
import java.awt.TextComponent;
import java.awt.Event.*;
import java.io.FileReader;
import java.io.BufferedReader;
import java.util.Scanner;
import javax.lang.model.element.VariableElement;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.JLabel;
import javax.swing.JTextArea;
import javax.swing.JButton;
import javax.swing.JSpinner;
import javax.swing.SpinnerModel;
import javax.swing.SpinnerNumberModel;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Scanner;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.Component;
import java.sql.*;
import java.util.Scanner;
import javax.swing.JFileChooser;
import javax.swing.JSplitPane;
import javax.swing.JLayeredPane;
import javax.swing.JDesktopPane;
import javax.swing.JComboBox;
import javax.swing.JSeparator;
import javax.swing.JTextField;
import javax.swing.JTextPane;
import javax.swing.SpinnerDateModel;
import javax.swing.border.CompoundBorder;
import javax.swing.border.LineBorder;
import javax.swing.text.JTextComponent;
import java.awt.Color;
import javax.swing.SwingConstants;
import java.awt.ComponentOrientation;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.util.Calendar;
import com.toedter.calendar.JDateChooser;
import javax.swing.JSpinner;
import org.eclipse.wb.swing.FocusTraversalOnArray;

public class Directory extends JFrame {
    private JPanel contentPane;
    private JTextField txtKeyword;
    private JTextField fileName;
    private JTextArea jTextArea1;
    private JDateChooser dateChooser;
    private JSpinner spinner_1;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Directory frame = new Directory();
                    frame.setVisible(true);
                    frame.setSize(450,630);
                    frame.fileName.requestFocus(); 
                    } catch (Exception e) {
                    e.printStackTrace();        
                }
            }
        });
    }
    public Directory() {

        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 436, 631);
        contentPane = new JPanel();
        contentPane.setAlignmentX(Component.LEFT_ALIGNMENT);
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);

        JLabel lblDirectory = new JLabel("Directory:");
        lblDirectory.setBounds(20, 29, 55, 24);
        contentPane.add(lblDirectory);

        JLabel lblDate = new JLabel("Date:");
        lblDate.setBounds(37, 141, 55, 24);
        contentPane.add(lblDate);

        txtKeyword = new JTextField();
        txtKeyword.setHorizontalAlignment(SwingConstants.CENTER);
        txtKeyword.setToolTipText("");
        txtKeyword.setColumns(10);
        txtKeyword.setBounds(85, 193, 229, 20);
        contentPane.add(txtKeyword);

        final JDateChooser dateChooser = new JDateChooser();
        dateChooser.setDateFormatString("YYYMMd");
        dateChooser.setBounds(85, 141, 229, 20);
        contentPane.add(dateChooser);

        JLabel lblKeyword = new JLabel("Keyword:");
        lblKeyword.setBounds(20, 191, 55, 24);
        contentPane.add(lblKeyword);

        JSeparator separator = new JSeparator();
        separator.setBounds(148, 204, -113, 34);
        contentPane.add(separator);

        JButton btnExport = new JButton("Export");
        btnExport.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {     
            }
        });
        btnExport.setBounds(324, 556, 89, 23);
        contentPane.add(btnExport);

        final JLabel Directory = new JLabel("");
        Directory.setBorder(new LineBorder(new Color(0, 0, 0)));
        Directory.setBounds(85, 30, 290, 22);
        contentPane.add(Directory);

        int min = 0;
        int max = 23;
        int step = 1;
        int initValue = 0;
        SpinnerModel sm = new SpinnerNumberModel(initValue, min, max, step);
        final JSpinner spinner_1 = new JSpinner(new SpinnerNumberModel(0, 0, 23-1, 1));

        spinner_1.setBounds(324, 143, 89, 20);
                contentPane.add(spinner_1);


        JButton btnNewButton = new JButton("...");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {

                JFileChooser chooser = new JFileChooser();
                chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
                chooser.showOpenDialog(null);
                File f = chooser.getSelectedFile();
                String filename =f.getAbsolutePath();
                Directory.setText(filename);

        });
        btnNewButton.setBounds(377, 30, 36, 23);
        contentPane.add(btnNewButton);

        final JTextArea jTextArea1 = new JTextArea();
        jTextArea1.setRows(15);
        jTextArea1.setColumns(15);
        jTextArea1.setBounds(42, 249, 351, 294);
        jTextArea1.setLineWrap(true);
        jTextArea1.setWrapStyleWord(true);
        contentPane.add(jTextArea1);
        jTextArea1.setEditable(false);

        JButton btnStart = new JButton("Start");
        btnStart.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {


                try{                
                    String filename =  fileName.getText();
                    FileReader fr = new FileReader(filename);
                    BufferedReader br = new BufferedReader(fr); 
                    Scanner scan = new Scanner(br);
                     filename = br.readLine();

                    if (filename != null){

                  String text = txtKeyword.getText();  
                  String line;
                  boolean hasError = true;

                while ((line = br.readLine()) != null) {

                if(line.contains(text)){
                    String newline = "\n";
                    jTextArea1.append(line + newline);
                    hasError = false;
                }   
                }
                if (hasError) {

                    JOptionPane.showMessageDialog(null, "Text Not Found");
                       br.close();
                       fr.close();
                    } 
                }}catch(IOException e){
                    JOptionPane.showMessageDialog(null, "File Not Found");
            }   }
        });

        btnStart.setBounds(324, 215, 89, 23);
        contentPane.add(btnStart);


        JLabel lblFileName_1 = new JLabel("File Name:");
        lblFileName_1.setBounds(20, 79, 75, 24);
        contentPane.add(lblFileName_1);


        fileName = new JTextField();
        fileName.setToolTipText("");
        fileName.setHorizontalAlignment(SwingConstants.CENTER);
        fileName.setColumns(10);
        fileName.setBounds(85, 81, 290, 20);
        contentPane.add(fileName);
        contentPane.setFocusTraversalPolicy(new FocusTraversalOnArray(new Component[]{fileName, lblDirectory, lblDate, txtKeyword, btnStart, lblKeyword, separator, btnExport, Directory, dateChooser, dateChooser.getCalendarButton(), spinner_1, btnNewButton, jTextArea1, lblFileName_1}));          
    }
}

文件是目录和名称的分类，例如

FileReader fr = new FileReader(filename);

try {
    FileReader fr = new FileReader(new File(Directory.getText(), filename));
    BufferedReader br = new BufferedReader(fr);
    //...
} catch (IOException e) {
    JOptionPane.showMessageDialog(null, "File Not Found");
}

问题2 您正在对文件执行某种不需要的先发制人读取

FileReader fr = new FileReader(new File(Directory.getText(), filename));

你应该开始读取文件，否则你就丢失了第一行文本

问题3 如果发生某种异常，您不会关闭流

if (filename != null){

    String text = txtKeyword.getText();  
    String line;
    boolean hasError = true;

    while ((line = br.readLine()) != null) {

如果由于某种原因，在您打开或读取流时发生异常，那么它们永远无法关闭……至少在JVM关闭之前是这样

相反，如果您使用的是Java 7+，您应该使用

try with resources

，或者使用

finally

块来确保流是关闭的，例如

FileReader fr = new FileReader(filename);

try {
    FileReader fr = new FileReader(new File(Directory.getText(), filename));
    BufferedReader br = new BufferedReader(fr);
    //...
} catch (IOException e) {
    JOptionPane.showMessageDialog(null, "File Not Found");
}

如果您至少转储了实际异常的堆栈跟踪，或者以某种方式将其记录下来，那么它对您也会有更大的帮助

BufferedReader br = null;
try {
    String filename = fileName.getText();
    br = new BufferedReader(new FileReader(new File(Directory.getText(), filename)));
    //...
} catch (IOException e) {
    JOptionPane.showMessageDialog(null, "File Not Found");
} finally {
    try {
        br.close();
    } catch (Exception e) {
    }
}

问题4

null

布局。像素完美布局在现代UI设计中是一种错觉，您无法控制字体、DPI、渲染管道或其他因素，这些因素将改变组件在屏幕上的渲染方式

---

Swing设计用于与布局管理器协作以克服这些问题。如果你坚持忽略这些特性，而违背API设计，那么就要准备好面对很多麻烦和永无止境的艰苦工作……

欢迎使用堆栈溢出！不要使用

null

布局。像素完美布局在现代UI设计中是一种错觉，您无法控制字体、DPI、渲染管道或其他因素，这些因素将改变组件在屏幕上的渲染方式。Swing设计用于与布局管理器协作以克服这些问题。如果你坚持忽略这些特性，反对API的设计，那么就要准备好面对很多令人头痛的事情，并且要做永无止境的艰苦工作……为什么要为目录和文件设置一个单独的字段呢？为什么不使用

JFileChooser

单步选择要读取的文件呢？它的工作原理就像我搜索目录一样。目录是固定的。然后我输入文件名并按下开始按钮，结果会弹出文件名。