Question

在我的程序中，我尝试将输出打印到文件但文件为空。该程序读取目录中的文本文件。我得到了所需的输出到控制台，但没有在output.text文件中。不确定程序中缺少什么。提前感谢您的帮助。

import java.io.*;

public class CacheData {

    public static void main(String[] args) throws IOException {
        String target_dir = "C:\\Files";
        String output = "C:\\Files\\output.txt";
        File dir = new File(target_dir);
        File[] files = dir.listFiles();

        for (File textfiles : files) {
            if (textfiles.isFile() && textfiles.getName().endsWith(".txt")) {
                BufferedReader inputStream = null;

                try {
                    inputStream = new BufferedReader(new FileReader(textfiles));
                    String line;

                    while ((line = inputStream.readLine()) != null) {
                        System.out.println(line);


                    PrintWriter outputStream = new PrintWriter(output);
                    outputStream.println();
                    outputStream.close();
                    }

                } finally {
                    if (inputStream != null) {
                        inputStream.close();

                    }
                }
            }
        }
    }

}

Answer 1

                    PrintWriter outputStream = new PrintWriter(output);

                    //you are not printing anything to output file.
                    outputStream.println();

                    //Change it to
                    outputStream.println(line);
                    outputStream.close();

Answer 2

对您的代码进行一些修改以写入您的文件。请参阅内联注释以获取更多信息。

import java.io.*;

public class CacheData {
public static void main(String[] args) throws IOException {
    String target_dir = "C:\\Files";
    String output = "C:\\Files\\output.txt";
    File dir = new File(target_dir);
    File[] files = dir.listFiles();

    for (File textfiles : files) {
        if (textfiles.isFile() && textfiles.getName().endsWith(".txt")) {
            BufferedReader inputStream = null;

            try {
                inputStream = new BufferedReader(new FileReader(textfiles));
                String line;
                //open the Printwriter before your loop
                PrintWriter outputStream = new PrintWriter(output);
                while ((line = inputStream.readLine()) != null) {
                    System.out.println(line);


                //Write Content not just linebreaks
                outputStream.println(line);

                }
                //close the outputstream after the loop
                outputStream.close();
            } finally {
                if (inputStream != null) {
                    inputStream.close();

                }
            }
        }
    }
}

}

要在文件中写入每个txt-File的内容，请在for循环之前移动Printwriter，然后在for循环之后关闭printwriter，而不仅仅是while循环。

Answer 3

您希望将多个文件（在您的案例中为文本文件）的内容合并到一个文件中。

这是一个更简单的IMO解决方案。更简单的是，您不必担心在读或写时自己打开和关闭文件。

public static void main(String[] args) throws Exception {
    String targetDir = "Path to your directory of input files";
    String outputFile = "Path to your output file";

    File dir = new File(targetDir);
    File[] files = dir.listFiles(new FilenameFilter() {
        // Only get files that end with .txt
        @Override
        public boolean accept(File dir, String name) {
            return name.toLowerCase().endsWith(".txt");
        }
    });

    // Read all file lines into a List
    List<String> inputFileLines = new ArrayList<>();
    for (File file : files) {
        inputFileLines.addAll(Files.readAllLines(Paths.get(file.getAbsolutePath())));
    }

    // Write the List to the console
    for (String line : inputFileLines) {
        System.out.println(line);
    }

    // Write the List to a single file
    Files.write(Paths.get(outputFile), inputFileLines, StandardOpenOption.CREATE);
}

如何读取/写入并组合多个.text文件的输出并创建单个.txt文件？

3 个答案: