How to load and read files in Gradle Project.

The Gradle Project Api has the following methods for using files.

1. file() - to load and read a particular file
2. files() - to load and read multiple files
3. fileTree() - to load and read file hierarchy in a directory or folder
4. zipTree() - to load and read a zip file (includes Jar , War and Ear files)
5. tarTree() - to load and read a tar file

How to list files inside a Zip file Jar File and Tar file

Lets say we have a file structure as shown in image below.

Following Gradle task will list the files inside a zip file, jar file and a tar file at the location "src/main/resources/archives/"

task showFiles(){
    doLast{
        FileTree zipFiles = zipTree("src/main/resources/archives/resources.zip");
        FileTree jarFiles = zipTree("src/main/resources/archives/resources.jar");
        FileTree tarFiles = tarTree("src/main/resources/archives/resources.tar.gz");

        println " \n#Contents of Zip File"
        zipFiles.each {
            println "${it.name}"
        }

        println " \n#Contents of Jar File"
        jarFiles.each {
            println "${it.name}"
        }

        println " \n#Contents of Tar File"
        tarFiles.each {
            println "${it.name}"
        }
    }
}

When we run the above gradle task using command gradle -q showFiles, it will give the following output.

 
#Contents of Zip File
file1.properties
sample1.txt
sample2txt
 
#Contents of Jar File
file1.properties
sample1.txt
sample2txt
 
#Contents of Tar File
sample1.txt
file1.properties
sample2txt

Read More

• How to Get a File using Relative Path
• How to Get Multiple Files using FileCollection
• How to Get all files in a Directory using FileTree
• Difference between File, FileCollection and FileTree in Gradle

Difference Between File, FileCollection and FileTree in Gradle

Difference Between File, FileCollection and FileTree

Suppose we have a directory structure as shown in image below.

We can write a gradle task as shown below

task loadFiles(){
    doLast{

        File file = file('src/main/resources/sample1.txt')
        println file.name
        println "\n"

        FileCollection collection = files('src/main/resources/sample1.txt','src/main/resources/sample2.txt')
        collection.each {
            println it.name
        }
        println "\n"

        FileTree tree = fileTree('src')
        tree.each {
            println it.name
        }
    }
}

When we run the above gradle task using command gradle -q loadFiles, it will give the following output.

sample1.txt


sample1.txt
sample2.txt


sample1.txt
sample2txt
file1.properties
A.java

Read More

• How to Get a File using Relative Path
• How to Get Multiple Files using FileCollection
• How to Get all files in a Directory using FileTree

Introduction to FileTree in Gradle Api

FileTree is an interface that extends FileCollection and introduces methods like matching() and visit(). It class represents a hierarchy of files in a given directory. It includes files in same folder and all sub folders.

How to get all files in a Directory

To load all files in a given directory and its sub directories you can use FileTree. Syntax for FileTree is as shown below.

FileTree tree = fileTree('path/to/dir')

The FileTree can get files in following ways

1. from relative path
2. from

We can write a gradle task to list all the files in the src folder as shown below.

task loadFiles(){
    doLast{
        FileTree tree = fileTree('src')
        tree.each {
            println it.name
        }
    }
}

When we run the aobe task using command gradle -q loadFiles it will give the following output

sample1.txt
sample2txt
file1.properties
A.java

Introduction to FileCollection

FileCollection is an interface that extends Iterable<File>, AntBuilderAware and Buildable interfaces.

How to load files in a FileCollection

Suppose we have a file structure as shown in image below

We can load multiple files for operation using the following syntax

FileCollection collection = files('relative/path/file1','absolute/path/file2',new File('file3'))

As shown in the example above we can load files in three ways

1. From a relative path
2. From a absolute path
3. From a File object.

We can write a gradle task to read all files in a folder or directory as follows

task fileTree(){
    doLast{
        FileTree tree = fileTree('src')
        tree.each {
            println it.name
        }
    }
}

Now when we run the above gradle task with the command gradle -q fileTree, it will give the following output

sample1.txt
sample2txt
file1.properties
resources.tar.gz
resources.jar
resources.zip
A.java

Operations and methods available for FileCollection

1. getSingleFile() - It returns a single file. (it will throw IllegalStateException if files contains more than one file or no file)
2. getAsFileTree() - It returns the FileCollection as a FileTree.
3. plus(FileCollection collection) - It will add the specified file collection to the existing file collection.
4. minus(FileCollection collection) - It will remove from the collection files in specified collection.
5. filter(Closure filter) - It will filter the files from collection and make changes to the same collection.

Read More

• How to Get a File using Relative Path
• How to Get Multiple Files using FileCollection
• How to Get all files in a Directory using FileTree
• Difference between File, FileCollection and FileTree in Gradle

How to read a file in Gradle Task

To load a file, you can take following three approaches

1. Load file using relative path

   File file = file('relative/path/file')
   

2. Load file using absolute path

   File file = file('absolute/path/file')
   

3. Load a file using File object

   File file = file(new File('somePath'))
   

Lets see how these three approaches work

task loadFiles << {
   println file('src/main/resources/file1.properties')
   println file('/home/ekiras/workspace/tutorials/gradle/src/main/resources/file1.properties')
   println file(new File('src/main/resources/file1.properties'))

}

When we run the above task using command gradle -q loadFiles it will give the following output

/home/ekiras/workspace/tutorials/gradle/src/main/resources/file1.properties
/home/ekiras/workspace/tutorials/gradle/src/main/resources/file1.properties
/home/ekiras/workspace/tutorials/gradle/src/main/resources/file1.properties

How to read a File in gradle task

Say, we have a file sample.txt in src/main/resources folder with the following context

I am some awesome text line 1
I am some awesome text line 2

Lets read this file in a gradle task.

task readFile(){
    doLast{
        File file = file('src/main/resources/sample.txt')
        println file.text
        println ""
        file.readLines().each{
            println it
        }

    }
}

Now when we run the command gradle -q readFile we will get the following output.

I am some awesome text line 1
I am some awesome text line 2

I am some awesome text line 1
I am some awesome text line 2

Read More

• How to Get a File using Relative Path
• How to Get Multiple Files using FileCollection
• How to Get all files in a Directory using FileTree