如果目录不存在,则创建一个目录,然后在该目录中创建文件

Question

条件是如果目录存在,它必须在该特定目录中创建文件而不创建新目录.

以下代码仅创建具有新目录但不适用于现有目录的文件.例如,目录名称将类似于"GETDIRECTION"

String PATH = "/remote/dir/server/";

String fileName = PATH.append(id).concat(getTimeStamp()).append(".txt");  

String directoryName = PATH.append(this.getClassName());   

File file  = new File(String.valueOf(fileName));

File directory = new File(String.valueOf(directoryName));

 if(!directory.exists()){

             directory.mkdir();
            if(!file.exists() && !checkEnoughDiskSpace()){
                file.getParentFile().mkdir();
                file.createNewFile();
            }
}
FileWriter fw = new FileWriter(file.getAbsoluteFile());
BufferedWriter bw = new BufferedWriter(fw);
bw.write(value);
bw.close();

Answer 1

Java 8+ 版本：

Files.createDirectories(Paths.get("/Your/Path/Here"));

在Files.createDirectories()创建不存在的一个新的目录和父目录。如果目录已经存在，此方法不会抛出异常。

Answer 2

此代码首先检查目录是否存在,如果没有则创建它,然后创建该文件.请注意,我无法验证您的一些方法调用,因为我没有完整的代码,所以我假设调用类似的东西getTimeStamp()并且getClassName()会起作用.您还应该对IOException使用任何java.io.*类时可能引发的可能做一些事情- 编写文件的函数应抛出此异常(并在其他地方处理),或者您应该直接在方法中执行此操作.此外,我假设id是类型String- 我不知道,因为您的代码没有明确定义它.如果它是一个类似的东西int,你可能应该把它转换为a String之前在fileName中使用它,就像我在这里所做的那样.

另外,我append用concat或+正如我认为的那样取代你的电话.

public void writeFile(String value){
    String PATH = "/remote/dir/server/";
    String directoryName = PATH.concat(this.getClassName());
    String fileName = id + getTimeStamp() + ".txt";

    File directory = new File(directoryName);
    if (! directory.exists()){
        directory.mkdir();
        // If you require it to make the entire directory path including parents,
        // use directory.mkdirs(); here instead.
    }

    File file = new File(directoryName + "/" + fileName);
    try{
        FileWriter fw = new FileWriter(file.getAbsoluteFile());
        BufferedWriter bw = new BufferedWriter(fw);
        bw.write(value);
        bw.close();
    }
    catch (IOException e){
        e.printStackTrace();
        System.exit(-1);
    }
}

如果你想在Microsoft Windows上运行代码,你可能不应该使用像这样的裸路径名 - 我不确定它将/在文件名中做什么.为了完全可移植性,您应该使用File.separator之类的东西来构建路径.

编辑:根据JosefScript的评论,没有必要测试目录的存在.如果它创建了一个目录,则该directory.mkdir() 调用将返回true,false如果没有,则包括该目录已存在的情况.

Answer 3

试图尽可能简短.如果目录不存在,则创建目录,然后返回所需的文件:

/** Creates parent directories if necessary. Then returns file */
private static File fileWithDirectoryAssurance(String directory, String filename) {
    File dir = new File(directory);
    if (!dir.exists()) dir.mkdirs();
    return new File(directory + "/" + filename);
}

Answer 4

我建议Java8 +以下内容.

/**
 * Creates a File if the file does not exist, or returns a
 * reference to the File if it already exists.
 */
private File createOrRetrieve(final String target) throws IOException{

    final Path path = Paths.get(target);

    if(Files.notExists(path)){
        LOG.info("Target file \"" + target + "\" will be created.");
        return Files.createFile(Files.createDirectories(path)).toFile();
    }
    LOG.info("Target file \"" + target + "\" will be retrieved.");
    return path.toFile();
}

/**
 * Deletes the target if it exists then creates a new empty file.
 */
private File createOrReplaceFileAndDirectories(final String target) throws IOException{

    final Path path = Paths.get(target);
    // Create only if it does not exist already
    Files.walk(path)
        .filter(p -> Files.exists(p))
        .sorted(Comparator.reverseOrder())
        .peek(p -> LOG.info("Deleted existing file or directory \"" + p + "\"."))
        .forEach(p -> {
            try{
                Files.createFile(Files.createDirectories(p));
            }
            catch(IOException e){
                throw new IllegalStateException(e);
            }
        });

    LOG.info("Target file \"" + target + "\" will be created.");

    return Files.createFile(
        Files.createDirectories(path)
    ).toFile();
}

Answer 5

码：

// Create Directory if not exist then Copy a file.


public static void copyFile_Directory(String origin, String destDir, String destination) throws IOException {

    Path FROM = Paths.get(origin);
    Path TO = Paths.get(destination);
    File directory = new File(String.valueOf(destDir));

    if (!directory.exists()) {
        directory.mkdir();
    }
        //overwrite the destination file if it exists, and copy
        // the file attributes, including the rwx permissions
     CopyOption[] options = new CopyOption[]{
                StandardCopyOption.REPLACE_EXISTING,
                StandardCopyOption.COPY_ATTRIBUTES

        };
        Files.copy(FROM, TO, options);


}

Answer 6

使用java.nio.Path它会很简单 -

public static Path createFileWithDir(String directory, String filename) {
        File dir = new File(directory);
        if (!dir.exists()) dir.mkdirs();
        return Paths.get(directory + File.separatorChar + filename);
    }