Question

我正在读大学，我们获得了一项创建程序的任务，该程序允许用户从他们的计算机打开文件并从所选文件中获取信息。我的任务的一部分陈述如下：

逐行搜索文件以获取给定字符串。输出必须包含行号，后跟包含搜索参数的行的内容。例如，给定以下搜索字符串：Java，程序将逐行搜索文件，生成如下结果：

5：在爪哇岛上 9：JAVA的人喜欢jaVa。

使用LineNumberReader类进行此练习。

我的代码如下，我不确定我做错了什么。没有语法错误，似乎只是一个逻辑错误。当我运行代码时，我能够获取文件描述，备份文件，获取字数，并正确退出，但当被要求搜索上面描述的单词时，我没有得到我应该得到的输出，它只给我字数，没有搜索结果。

主类

import java.io.*;
import java.util.ArrayList;
import javax.swing.*;

public class BasicFile {

File file1;
JFileChooser selection;
File file2 = new File(".", "Backup File");

public BasicFile() {
    selection = new JFileChooser(".");
}

public void selectFile() {
    int status = selection.showOpenDialog(null);

    try {
        if (status != JFileChooser.APPROVE_OPTION) {
            throw new IOException();
        }
        file1 = selection.getSelectedFile();

        if (!file1.exists()) {
            throw new FileNotFoundException();
        }
    } catch (FileNotFoundException e) {
        JOptionPane.showMessageDialog(null, "File Not Found ", "Error", JOptionPane.INFORMATION_MESSAGE);
    } catch (IOException e) {
        System.exit(0);
    }
}

void backupFile() throws FileNotFoundException {
    DataInputStream in = null;
    DataOutputStream out = null;
    try {
        in = new DataInputStream(new FileInputStream(file1));
        out = new DataOutputStream(new FileOutputStream(file2));

        try {
            while (true) {
                byte data = in.readByte();
                out.writeByte(data);
            }
        } catch (EOFException e) {
            JOptionPane.showMessageDialog(null, "Success!!!",
                    "Backup Complete!", JOptionPane.INFORMATION_MESSAGE);
        } catch (IOException e) {
            JOptionPane.showMessageDialog(null, "File Not Found ",
                    "Error", JOptionPane.INFORMATION_MESSAGE);
        }
    } finally {
        try {
            in.close();
            out.close();
        } catch (Exception e) {
            display(e.toString(), "Error");
        }
    }

}

boolean exists() {
    return file1.exists();
}

public String toString() {
    return file1.getName() + "\n" + file1.getAbsolutePath() + "\n" + file1.length() + " bytes";
}

public String words() {
    try {
        int words = 0;
        int numbers = 0;
        int lines = 1;
        int characters = 0;
        int total = 0;

        String c = " ";

        FileReader r = new FileReader(file1);
        LineNumberReader lnr = new LineNumberReader(r);
        StreamTokenizer t = new StreamTokenizer(r);
        ArrayList<String> results = new ArrayList<String>();

        t.resetSyntax();
        t.wordChars('0', '9');
        t.wordChars('A', 'Z');
        t.wordChars('a', 'z');
        t.whitespaceChars(0, ' ');

        t.eolIsSignificant(true);

        while (t.nextToken() != StreamTokenizer.TT_EOF) {
            switch (t.ttype) {
                case StreamTokenizer.TT_NUMBER:
                    numbers++;
                    break;
                case StreamTokenizer.TT_WORD:
                    characters += t.sval.length();
                    words++;
                    break;
                case StreamTokenizer.TT_EOL:
                    lines++;
                    break;
                case StreamTokenizer.TT_EOF:
                    break;
                default:

            }
        }

        BufferedReader bf = new BufferedReader(new FileReader(file1));
        BufferedWriter out = new BufferedWriter(new FileWriter("test.txt"));
        BufferedWriter output = new BufferedWriter(new FileWriter("output.txt"));
        int recCount = 0;
        String record = null;
        while ((record = bf.readLine()) != null) {
            recCount++;
            out.write(recCount + ": " + record);
            out.newLine();
        }
        out.close();

        String ask = "Enter Word";

        String find = JOptionPane.showInputDialog(ask);
        String word = find;

        String line = null;
        while ((line = lnr.readLine()) != null) {
            if (line.indexOf(word) >= 0) {
                results.add(lnr.getLineNumber() + line);
            }
        }

        r.close();

        total = numbers + words;

        lnr.close();

        return file1.getName() + " has " + lines + " lines, "
                + total + " words, "
                + characters + " characters. ";
    } catch (IOException e) {
        display(e.toString(), "Error");
    }

    return " ";

}

void display(String msg, String s) {
    JOptionPane.showMessageDialog(null, msg, s, JOptionPane.ERROR_MESSAGE);
}

}

测试类

import java.io.*;
import javax.swing.*;

public class TestBasicFile {

public static void main(String[] args) throws FileNotFoundException, IOException {

    boolean done = false;

    String menu = "Enter option\n1. Open File\n2. Backup File\n3. "
            + "Word Count\n4. Exit";

    while (!done) {
        BasicFile f = new BasicFile();

        String s = JOptionPane.showInputDialog(menu);

        try {
            int i = Integer.parseInt(s);

            switch (i) {
                case 1:
                    JOptionPane.showMessageDialog(null, "When the file is selected, the name, path, and size will be displayed",
                            "File Selection", JOptionPane.INFORMATION_MESSAGE);

                    f.selectFile();

                    if (f.exists()) {
                        displayInfo(f.toString(), "File");
                    } else {
                        f.selectFile();
                    }
                    break;

                case 2:

                    f.selectFile();

                    if (f.exists()) {
                        displayInfo(f.toString(), "File");
                    } else {
                        f.selectFile();
                    }

                    f.backupFile();
                    break;

                case 3:
                    f.selectFile();

                    if (f.exists()) {
                        displayInfo(f.words(), "Word Count");
                    } else {
                        f.selectFile();
                    }
                    break;

                case 4:

                    done = true;
                    break;
                default:
            }
        } catch (NumberFormatException e) {
            System.exit(0);
        } catch (NullPointerException e) {
            System.exit(0);
        }
    }
}

static void displayInfo(String s, String info) {
    JOptionPane.showMessageDialog(null, s, info, JOptionPane.INFORMATION_MESSAGE);
}

}

Answer 1

您将结果放在结果列表中，但从不打印。

搜索文件：初学者代码

1 个答案: