Java I/O 写入、mixcase 和 getExtension 问题

Question

我正在更改目录中所有文件的名称，如果它是文本文件，我正在更改内容，但它似乎不起作用，文件名已正确更改，但内容为空白/消失，这是我的代码:

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import org.apache.commons.io.FilenameUtils;

public class FileOps {
    public static File folder = new File(
            "C:\\Users\\N\\Desktop\\New folder\\RenamingFiles\\src\\renaming\\Files");
    public static File[] listOfFiles = folder.listFiles();

    public static void main(String[] argv) throws IOException {
        toUpperCase();
    }

    public static void toUpperCase() throws FileNotFoundException {
        for (int i = 0; i < listOfFiles.length; i++) {
            if (listOfFiles[i].isFile()) {
                String newname = mixCase(listOfFiles[i].getName());

                if (listOfFiles[i].renameTo(new File(folder, newname))) {
                    String extension = FilenameUtils
                            .getExtension(listOfFiles[i].getName());
                    if (extension.equals("txt") || extension.equals("pdf")
                            || extension.equals("docx")
                            || extension.equals("log")) {
                        rewrite(listOfFiles[i]);

                        System.out.println("Done");
                    }

                }
            } else {
                System.out.println("Nope");
            }
        }
    }

    public static String mixCase(String in) {
        StringBuilder sb = new StringBuilder();
        if (in != null) {
            char[] arr = in.toCharArray();
            if (arr.length > 0) {
                char f = arr[0];
                boolean first = Character.isUpperCase(f);
                for (int i = 0; i < arr.length; i++) {
                    sb.append((first) ? Character.toLowerCase(arr[i])
                            : Character.toUpperCase(arr[i]));
                    first = !first;
                }
            }
        }
        return sb.toString();
    }

    public static void rewrite(File file) throws FileNotFoundException {
        FileReader reader = new FileReader(file.getAbsolutePath());
        BufferedReader inFile = new BufferedReader(reader);

        try {
            FileWriter fwriter = new FileWriter(file.getAbsolutePath());
            BufferedWriter outw = new BufferedWriter(fwriter);
            while (inFile.readLine() != null) {
                String line = mixCase(inFile.readLine());
                outw.write(line);
            }
            inFile.close();
            outw.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 1

您的代码存在几个问题:

1. 您的rewrite函数是在旧名称File上执行的。应该在重命名的文件上完成:

       String newname = mixCase(listOfFiles[i].getName());
       File renamedFile = new File(folder, newname);
       if (listOfFiles[i].renameTo(renamedFile )) {
           String extension = FilenameUtils
                   .getExtension(listOfFiles[i].getName());
           if (extension.equals("txt") || extension.equals("pdf")
                   || extension.equals("docx")
                   || extension.equals("log")) {
               rewrite(renamedFile);
   
               System.out.println("Done");
           }
   
       }
   

2. 您正在尝试像常规文本文件一样阅读docx和pdf文件。这是行不通的。您将必须使用外部库，例如 POI和 pdf Box

3. 您的rewrite函数不安全。您必须不确定是否关闭资源:

    FileReader reader = null;
    BufferedReader inFile = null;
   
   try {
   reader = new FileReader(file.getAbsolutePath());
   inFile = new BufferedReader(reader);
   FileWriter fwriter = new FileWriter(file.getAbsolutePath());
   BufferedWriter outw = new BufferedWriter(fwriter);
   
   while (inFile.readLine() != null) {
       String line = mixCase(inFile.readLine());
       outw.write(line);
   }
   
   } catch (IOException e) {
   e.printStackTrace();
   }finally
   {
      if(infile != null)
      inFile.close();
   
      if(reader != null)
      reader .close();
   }