读取内容后移动文件

Question

我想创建一个 Quartz 作业，它读取 .csv 文件并在处理文件时移动它们。我试过这个：

@Override
public void execute(JobExecutionContext context) {

    File directoryPath = new File("C:\\csv\\nov");
    // Create a new subfolder called "processed" into source directory
    try {
        Files.createDirectory(Path.of(directoryPath.getAbsolutePath() + "/processed"));
    } catch (IOException e) {
        throw new RuntimeException(e);
    }

    FilenameFilter textFileFilter = (dir, name) -> {
        String lowercaseName = name.toLowerCase();
        if (lowercaseName.endsWith(".csv")) {
            return true;
        } else {
            return false;
        }
    };
    // List of all the csv files
    File filesList[] = directoryPath.listFiles(textFileFilter);
    System.out.println("List of the text files in the specified directory:");
    for(File file : filesList) {

        try {
            List<CsvLine> beans = new CsvToBeanBuilder(new FileReader(file.getAbsolutePath(), StandardCharsets.UTF_16))
                    .....
                    .build()
                    .parse();

            for(CsvLine item: beans){

                    ....... sql queries

                    Optional<ProcessedWords> isFound = processedWordsService.findByKeyword(item.getKeyword());

                    ......................................
            }

        } catch (Exception e){
            e.printStackTrace();
        }

        // Move here file into new subdirectory when file processing is finished
        Path copied = Paths.get(file.getAbsolutePath() + "/processed");
        Path originalPath = file.toPath();
        try {
            Files.move(originalPath, copied, StandardCopyOption.REPLACE_EXISTING);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

文件夹 processed 是在作业启动时创建的，但出现异常：

    org.quartz.SchedulerException: Job threw an unhandled exception.
        at org.quartz.core.JobRunShell.run(JobRunShell.java:213) ~[quartz-2.3.2.jar:na]
        at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:573) ~[quartz-2.3.2.jar:na]
    Caused by: java.lang.RuntimeException: java.nio.file.FileSystemException: C:\csv\nov\07_06_26.csv -> C:\csv\nov\07_06_26.csv\processed: The process cannot access the file because it is being used by another process
        at com.wordscore.engine.processor.ImportCsvFilePostJob.execute(ImportCsvFilePostJob.java:114) ~[main/:na]
        at org.quartz.core.JobRunShell.run(JobRunShell.java:202) ~[quartz-2.3.2.jar:na]
        ... 1 common frames omitted
    Caused by: java.nio.file.FileSystemException: C:\csv\nov\07_06_26.csv -> C:\csv\nov\

07_06_26.csv\processed: The process cannot access the file because it is being used by another process
    at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:92) ~[na:na]
    at java.base/sun.nio.fs.WindowsException.rethrowAsIOException(WindowsException.java:103) ~[na:na]

你知道我如何释放文件并将其移动到子目录中吗？

编辑：使用 try-catch 更新代码

@Override
public void execute(JobExecutionContext context) {

    File directoryPath = new File("C:\\csv\\nov");
    // Create a new subfolder called "processed" into source directory
    try {
        Path path = Path.of(directoryPath.getAbsolutePath() + "/processed");
        if (!Files.exists(path) || !Files.isDirectory(path)) {
            Files.createDirectory(path);
        }
    } catch (IOException e) {
        throw new RuntimeException(e);
    }

    FilenameFilter textFileFilter = (dir, name) -> {
        String lowercaseName = name.toLowerCase();
        if (lowercaseName.endsWith(".csv")) {
            return true;
        } else {
            return false;
        }
    };
    // List of all the csv files
    File filesList[] = directoryPath.listFiles(textFileFilter);
    System.out.println("List of the text files in the specified directory:");
    for(File file : filesList) {

        try {
            try (var br = new FileReader(file.getAbsolutePath(), StandardCharsets.UTF_16)){
                List<CsvLine> beans = new CsvToBeanBuilder(br)
                        ......
                        .build()
                        .parse();

            for (CsvLine item : beans) {

                .....
                if (isFound.isPresent()) {
                    .........
        }}

        } catch (Exception e){
            e.printStackTrace();
        }

        // Move here file into new subdirectory when file processing is finished
        Path copied = Paths.get(file.getAbsolutePath() + "/processed");
        Path originalPath = file.toPath();
        try {
            Files.move(originalPath, copied, StandardCopyOption.REPLACE_EXISTING);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

Answer 1

new FileReader(file.getAbsolutePath(), StandardCharsets.UTF_16)

这部分创建一个资源.资源是代表底层重物的对象——你可以拥有的东西很少。在这种情况下，它表示底层操作系统文件句柄。

您必须始终安全地关闭这些.实际上只有两种方法可以正确地做到这一点：

• 使用 try-with-resources
• 将其保存到一个字段中，并使自己成为AutoClosable，以便使用此类实例的代码可以使用 try-with-resources

try (var br = new FileReader(file, StandardCharsets.UTF_16)) {
  List<CsvLine> beans = new CsvToBeanBuilder(br)
                    .....
                    .build()
                    .parse();
}

是答案。