如何根据操作系统更改文件路径

Question

i have a class which reads the list available in particular location,

the following is my code,

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class ExceptionInFileHandling {

   @SuppressWarnings({ "rawtypes", "unchecked" })
   public static void GetDirectory(String a_Path, List a_files, List a_folders) throws IOException {
       try {
           File l_Directory = new File(a_Path);
           File[] l_files = l_Directory.listFiles();

           for (int c = 0; c < l_files.length; c++) {
               if (l_files[c].isDirectory()) {
                   a_folders.add(l_files[c].getName());
               } else {
                   a_files.add(l_files[c].getName());
               }
           }
       } catch (Exception ex){
           ex.printStackTrace();
       }

   }
   @SuppressWarnings("rawtypes")
   public static void main(String args[]) throws IOException {

       String filesLocation = "asdfasdf/sdfsdf/";
       List l_Files = new ArrayList(), l_Folders = new ArrayList();
       GetDirectory(filesLocation, l_Files, l_Folders);

       System.out.println("Files");
       System.out.println("---------------------------");
       for (Object file : l_Files) {
           System.out.println(file);
       }
       System.out.println("Done");

   }
}

in this the file path can be passed as argument and that should be taken up based on the OS,

filePath.replaceAll("\\\\|/", "\\" + System.getProperty("file.separator"))

is this correct?

Answer 1

There are better ways to use file paths...

// Don't do this
filePath.replaceAll("\\\\|/", "\\" + System.getProperty("file.separator"))

Use java.nio.file.path :

import java.nio.file.*;

---

Path path = Paths.get(somePathString);
// Here is your system independent path
path.toAbsolutePath();
// Or this works too
Paths.get(somePathString).toAbsolutePath();

Use File.seperator :

// You can also input a String that has a proper file seperator like so
String filePath = "SomeDirectory" + File.separator;
// Then call your directory method
try{
    ExceptionInFileHandling.GetDirectory(filePath, ..., ...);
} catch (Exception e){}

---

So a simple change to your method will now work cross platform:

@SuppressWarnings({ "rawtypes", "unchecked" })
   public static void GetDirectory(String a_Path, List a_files, List a_folders) throws IOException {
       try {
           // File object is instead constructed 
           // with a URI by using Path.toUri()
           // Change is done here
           File l_Directory = new File(Paths.get(a_Path).toUri());

           File[] l_files = l_Directory.listFiles();
           for (int c = 0; c < l_files.length; c++) {
               if (l_files[c].isDirectory()) {
                   a_folders.add(l_files[c].getName());
               } else {
                   a_files.add(l_files[c].getName());
               }
           }
       } catch (Exception ex){
           ex.printStackTrace();
       }

   }

Answer 2

在调用File构造函数时，也可以在Windows上使用正斜杠作为目录分隔符。

Answer 3

why you are not adding java defined file separator instead of creating a string then replacing all. try it like

String filesLocation = "asdfasdf"+File.separator+"sdfsdf"+File.separator;

Answer 4

The answer from you should be correct. There is another similiar thread with answer :

Java regex to replace file path based on OS

Platform independent paths in Java

Answer 5

First, you should not used relative path like asdfasdf/sdfsdf/ . It's a big source of bugs as your path depends on your working directory.

That thing said, your replaceAll is quite good but it can be improved like this :

filePath.replaceAll(
    "[/\\\\]+",
    Matcher.quoteReplacement(System.getProperty("file.separator")));

Using quoteReplacement is adviced in replaceAll documentation

Returns a literal replacement String for the specified String. This method produces a String that will work as a literal replacement s in the appendReplacement method of the Matcher class. The String produced will match the sequence of characters in s treated as a literal sequence. Slashes ('\\') and dollar signs ('$') will be given no special meaning.

Answer 6

You could generate a Path object from the passed argument. Then you would not need to handle the file separator on your own.

public static void main(String[] args) {
    Path path = Paths.get(args[0]);
    System.out.println("path = " + path.toAbsolutePath());
}

The code is able to handle following passed arguments.

• foo\\bar
• foo/bar
• foo\\bar/baz
• foo\\\\bar
• foo//baz
• foo\\\\bar//baz
• ...

Answer 7

You need to use java.io.File.separatorChar to The system-dependent default name-separator character.

String location = "usr"+java.io.File.separatorChar+"local"+java.io.File.separatorChar;

Answer 8

org.apache.commons.io.FilenameUtils包含许多有用的方法，例如separatorsToSystem（String path）根据您使用的操作系统转换给定路径中的分隔符。

Answer 9

使用以下方法了解OS文件分隔符，然后使用此方法替换所有以前的分隔符。

System.getProperty("file.separator");

Answer 10

Why you just dont use "/". It is acceptable for both linux and windows as path seperator.