如何从文本文件中删除特定内容？

Question

我在 java 中的 SO 的帮助下从事这个项目，我正在读取一个文件夹，然后将内容写入文件。然后我需要浏览该内容，只保留最后有 Thumbnail.jpg 的图像。

编辑：

 public static final File outFile = new File(System.getProperty("user.home") + "/Desktop/output.txt");

public static void main(String[] args) throws IOException {
    getFileContents();
}

public static void getFileContents() throws IOException{

    System.out.print(outFile.getAbsolutePath());
    PrintWriter out = new PrintWriter(outFile);

        Files.walk(Paths.get("C:/Location")).forEach(filePath -> {
            //this is where I would like to happen
            if (Files.isRegularFile(filePath)) // I was thinking I could use filePath.endsWith("Thumbnail.jpg")
                    out.println(filePath);
        }); 
    out.close();
}

Answer 1

你可以这样做

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Main {
  public static void main(String[] args)  {
    // My test file. Change to your path 
    File file = new File("/home/andrew/Desktop/File.txt");
    if (!file.exists()) {
        throw new RuntimeException("File not found");
    }

    try {
        Scanner scanner = new Scanner(file);

        //now read the file line by line...
        int lineNum = 0;
        while (scanner.hasNextLine()) {
            String line = scanner.nextLine();
            lineNum++;
            // If Thumbnail.jpg is anyone where on the line
            if(line.contains("Thumbnail.jpg")){
                // print the line for example. You can do whatever you what with it now 
                System.out.println("Found item on line: " +lineNum);
            }
        }
    } catch(FileNotFoundException e) { 
        //handle this
    }

  }
}

Answer 2

File inputFile = new File("File.txt");
File tempFile = new File("File1.txt");
BufferedReader reader = new BufferedReader(new FileReader(inputFile));
BufferedWriter writer = new BufferedWriter(new FileWriter(tempFile));
String lineToRemove = "Thumbnil.jpg";
String currentLine;
 while((currentLine = reader.readLine()) != null) {
String trimmedLine = currentLine.trim();
if(trimmedLine.equals(lineToRemove)) continue;
writer.write(currentLine + System.getProperty("line.separator"));
 }
writer.close(); 
reader.close(); 
boolean successful = tempFile.renameTo(inputFile);

Answer 3

我只是想感谢大家的帮助，但经过反复试验，我找到了解决问题的方法。这就是我解决问题的方法，我创建了两种方法

一种创建包含所有文件夹内容的文件的方法。
一种获取此文件并创建新文件的方法所选内容。

然后我就用 main 方法调用了它们。然后您只需继续删除您的第一个文件。

    // this is the input file from the folder
    public static final File outFile = new File("input.txt");

    public static void main(String[] args) throws IOException {     
        getFileContents();
        changeFileContents();
    }

    // this method takes all the folder contents and puts
    // it into a text file
    public static void getFileContents() throws IOException{

        System.out.print(outFile.getAbsolutePath());
        PrintWriter out = new PrintWriter(outFile);

            Files.walk(Paths.get("C:/Location")).forEach(file -> {
                if (Files.isRegularFile(file))
                        out.println(file);
            }); 
        out.close();
    }

    // this method takes the previously made text file and makes
    // a new one only adding the file names with Thumbnail.jpg
    public static void changeFileContents() throws IOException {

        PrintWriter in = new PrintWriter(new FileWriter("output.txt"));

        Scanner scanner = new Scanner(outFile);
            while (scanner.hasNextLine()) {
                String line = scanner.nextLine();
                // checks to see if the image is the one I need
                if(line.contains("Thumbnail.jpg"))
                    in.println(line);
            }
        scanner.close();
        in.close();
     }

如何从文本文件中删除特定内容？

How do I remove specific contents from a text file?

java

directory

file