How To Re-Create Not Empty Directory Alongside Files Inwards Coffee Vii - Example Tutorial

It's slow to re-create a file or empty directory inwards Java equally y'all tin travel Files.copy(fromPath, toPath) from Java 7, but, unfortunately, it's non equally slow to re-create a non-empty directory alongside all its files in addition to subdirectories inwards Java, much similar deleting a non-empty directory. There is no method inwards Java IO API which copies everything within ane directory to another. The copy(source, target, CopyOption...) method tin re-create directories, but files within the directories are non copied. So the new directory volition live empty fifty-fifty if the master copy directory contains files in addition to folders. Similarly, the re-create fails if target directory already exists, unless the REPLACE_EXISTING re-create choice is specified. No dubiety that NIO 2 of Java vii has made life easier for Java programmers in addition to provides useful tools to bargain alongside files in addition to directories, the onus is forthwith on Java developers to acquire in addition to brand the best travel of it. If y'all to acquire to a greater extent than near NIO 2 features, see here.

In this article, I'll present y'all 2 ways to re-create a directory alongside files inwards Java. The kickoff choice is past times using FileUtils cast from Apache Commons IO. You tin travel FileUtils.copyDirectory(src, target) method to re-create or backup directories inwards Java.

The minute instance volition re-create directory construction inwards using NIO2 of Java 7. It travel volition travel a recursive algorithm to re-create the directory inwards Java. To acquire to a greater extent than near JDK vii novel File API in addition to other features, y'all tin see Core Java For the Impatient. This contains many, slow to empathise examples to chop-chop acquire novel features of Java vii including the novel file API in addition to it also covers Java SE 8.

Copy Directory using Apache Commons IO FileUtils class

This was the simplest means to recursively re-create a directory alongside sum file construction prior to Java vii world. It is even thus rattling useful to many Java developers similar me who e'er travel Apache Commons library inwards their Java projects. In gild to travel Apache Commons IO, y'all take to include next Maven dependency:

<dependency>      <groupId>commons-io</groupId>      <artifactId>commons-io</artifactId>      <version>2.4</version> </dependency>

in addition to hither is the sample Java business office which copies a directory alongside files inwards exactly ane line. That's the practise goodness of library methods, it makes your code to a greater extent than readable. No doubt, why Joshua Bloch has recommended to acquire in addition to travel library methods inwards his classic Effective Java.

public static void copyDirectoryUsingApache(String from, String to) throws IOException{         File source = new File(from);         File target = new File(to);               FileUtils.copyDirectory(source, target);      }

You tin come across that how slow to re-create a sum directory inwards Java alongside exactly ane business of code. Yes, y'all tin take kickoff 2 lines of code which are converting String to File object, if y'all lead overstep File object. Though if y'all convey file names equally String, it's meliorate to travel the method inwards this format.

Java Program to Copy a Non-Empty Directory

In gild to re-create a file or a directory inwards JDK 1.7,  simply calling Files.copy(fromPath, toPath) is enough, but it volition alone piece of job if source directory is non empty. In gild to re-create a directory alongside files in addition to subdirectories, y'all take to write your ain Java programme to re-create whole directory construction inwards Java equally shown below. This method uses recursion to re-create all files in addition to folder from the directory.

public static void copyDirectory(File sourceDir, File targetDir)  throws IOException {         if (sourceDir.isDirectory()) {             copyDirectoryRecursively(sourceDir, targetDir);         } else {             Files.copy(sourceDir.toPath(), targetDir.toPath());         }     } 

// recursive method to re-create directory in addition to sub-diretory inwards Java private static void copyDirectoryRecursively(File source, File target)  throws IOException {         if (!target.exists()) {             target.mkdir();         }          for (String kid : source.list()) {             copyDirectory(new File(source, child), new File(target, child));         }     }

The method copyDirectory(File src, File dest) kickoff checks if src File object points to a directory or non if it does thus it telephone phone the recursive method to re-create the directory, but if it doesn't thus it exactly copy the file using Files.copy() method. It also creates the target directory if it doesn't exists. If the directory already exists in addition to y'all travel REPLACE_EXISTING choice thus it volition overwrite it.

There are a yoke of to a greater extent than re-create options which are useful e.g. COPY_ATTRIBUTE, which copies the file attribute e.g. permissions to the target file land copying. The exact file attributes supported are file arrangement in addition to platform dependent, but last-modified-time is supported across the platform in addition to copied to the target file.

Another affair to Federal Reserve annotation is whether to re-create the soft links or not. It's possible that your directory may comprise symbolic links. The re-create method copies the target of the link, instead of the link itself. So if y'all desire to re-create the link itself, in addition to non the target of the link, specify either the NOFOLLOW_LINKS or REPLACE_EXISTING option

Here is how our newly copied directory looks like, when I used this method to re-create an existing directory inwards my laptop.

That's all near how to re-create nonempty directory inwards Java alongside files in addition to folders. If y'all are non running inwards Java 7, though y'all should because it has lots of functioning improvement, y'all tin travel Apache Commons IO to re-create the directories alongside files in addition to folder inwards Java. If y'all are running on JRE vii thus y'all tin write your ain recursive method using Files.copy() method in addition to diverse CopyOption e.g. RELACE_EXISTING, COPY_ATTRIBUTE, in addition to NOFOLLOW_LINKS.

Further Learning
Complete Java Masterclass
Java Fundamentals: The Java Language
Java In-Depth: Become a Complete Java Engineer!

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