如何检查文件夹是否存在

I am playing a bit with the new Java 7 IO features, actually I trying to receive all the xml files of a folder. But this throws an exception when the folder does not exist, how can I check if the folder exists with the new IO?

我正在使用新的Java 7 IO特性，实际上我尝试接收一个文件夹的所有xml文件。但是当文件夹不存在时，这会抛出异常，我如何检查这个文件夹是否与新的IO一起存在?

public UpdateHandler(String release) {
    log.info("searching for configuration files in folder " + release);
    Path releaseFolder = Paths.get(release);
    try(DirectoryStream<Path> stream = Files.newDirectoryStream(releaseFolder, "*.xml")){

        for (Path entry: stream){
            log.info("working on file " + entry.getFileName());
        }
    }
    catch (IOException e){
        log.error("error while retrieving update configuration files " + e.getMessage());
    }


}

9 个解决方案

#1

174

Using java.nio.file.Files:

使用java.nio.file.Files:

Path path = ...;

if (Files.exists(path)) {
    // ...
}

You can optionally pass this method LinkOption values:

您可以选择传递此方法LinkOption值:

if (Files.exists(path, LinkOption.NOFOLLOW_LINKS)) {

There's also a method notExists:

还有一种方法不存在:

if (Files.notExists(path)) {

#2

157

Quite simple:

很简单:

new File("/Path/To/File/or/Directory").exists();

And if you want to be certain it is a directory:

如果你想确定它是一个目录:

File f = new File("/Path/To/File/or/Directory");
if (f.exists() && f.isDirectory()) {
   ...
}

#3

To check if a directory exists with the new IO:

检查一个目录是否存在新的IO:

if (Files.isDirectory(Paths.get("directory"))) {
  ...
}

isDirectory returns true if the file is a directory; false if the file does not exist, is not a directory, or it cannot be determined if the file is a directory or not.

如果文件是目录，则isDirectory返回true;如果该文件不存在，不是目录，或者无法确定该文件是否为目录，则为false。

See: documentation.

看:文档。

#4

You need to transform your Path into a File and test for existence:

您需要将路径转换为文件并测试是否存在:

for(Path entry: stream){
  if(entry.toFile().exists()){
    log.info("working on file " + entry.getFileName());
  }
}

#5

Generate a file from the string of your folder directory

从文件夹目录的字符串生成一个文件

String path="Folder directory";    
File file = new File(path);

and use method exist.
If you want to generate the folder you sould use mkdir()

和使用方法存在。如果您想要生成文件夹，您可以使用mkdir()

if (!file.exists()) {
            System.out.print("No Folder");
            file.mkdir();
            System.out.print("Folder created");
        }

#6

File sourceLoc=new File("/a/b/c/folderName");
boolean isFolderExisted=false;
sourceLoc.exists()==true?sourceLoc.isDirectory()==true?isFolderExisted=true:isFolderExisted=false:isFolderExisted=false;

#7

There is no need to separately call the exists() method, as isDirectory() implicitly checks whether the directory exists or not.

不需要单独调用exist()方法，因为isDirectory()隐式地检查目录是否存在。

#8

We can check files and thire Folders.

我们可以检查文件和文件夹。

import java.io.*;
public class fileCheck
{
    public static void main(String arg[])
    {
        File f = new File("C:/AMD");
        if (f.exists() && f.isDirectory()) {
        System.out.println("Exists");
        //if the file is present then it will show the msg  
        }
        else{
        System.out.println("NOT Exists");
        //if the file is Not present then it will show the msg      
        }
    }
}

#9

import java.io.File;
import java.nio.file.Paths;

public class Test
{

  public static void main(String[] args)
  {

    File file = new File("C:\\Temp");
    System.out.println("File Folder Exist" + isFileDirectoryExists(file));
    System.out.println("Directory Exists" + isDirectoryExists("C:\\Temp"));

  }

  public static boolean isFileDirectoryExists(File file)

  {
    if (file.exists())
    {
      return true;
    }
    return false;
  }

  public static boolean isDirectoryExists(String directoryPath)

  {
    if (!Paths.get(directoryPath).toFile().isDirectory())
    {
      return false;
    }
    return true;
  }

}

#1

174