Gradle 任务访问文件的几种方式

例子：

三种方式，使用

task file{
  // relative path
  File configFile = file('build.gradle')
  println 'relative path: ' + configFile

  // Using an absolute path
  configFile = file(configFile.absolutePath)
  println 'absolute path: ' + configFile.absolutePath + ' = ' + configFile

  // Using a File object with a relative path
  configFile = file(new File('build.gradle'))  
  println 'file object: ' + configFile
}

输出：

relative path: C:\temp\quickstart\groovy\build.gradle
absolute path: C:\temp\quickstart\groovy\build.gradle = C:\temp\quickstart\groovy\build.gradle
file object: C:\temp\quickstart\groovy\build.gradle

文件集合的创建方式和使用

FileCollection collection = files('build.gradle', new File('other.gradle'), ['settings.gradle', '.gradle/6.0/gc.properties'])  

  println "collection: " + collection

  collection.each {File file ->
    println 'file name:' + file.name
  }

输出：

这个元素为File的文件集合可以转换成其他的Groovy数据结构：

// Convert the collection to various types
Set set = collection.files
Set set2 = collection as Set
List list = collection as List
String path = collection.asPath
File file = collection.singleFile
File file2 = collection as File
// 也可以使用代码往集合里添加或者删除元素
def union = collection + files('src/file3.txt')
def different = collection - files('src/file3.txt')  

文件集合的自定义实现方式

task file {
    File srcDir
    // Create a file collection using a closure
    FileCollection collection = files { srcDir.listFiles() }
    srcDir = file('src')
    println "Contents of $srcDir.name"
    collection.collect { relativePath(it) }.sort().each { println it }
    srcDir = file('.gradle')
    println "Contents of $srcDir.name"
    collection.collect { relativePath(it) }.sort().each { println it }
}  

输出：

Contents of src
src\main
src\test
Contents of .gradle
.gradle\6.0
.gradle\buildOutputCleanup

文件树

文件树是按层次结构排序的文件集合。例如，文件树可能表示一个目录树或 ZIP 文件的内容。它通过 FileTree 接口表示。FileTree 接口继承自 FileCollection，所以你可以用对待文件集合一样的方式来对待文件树。Gradle 中的几个对象都实现了 FileTree 接口，例如 source sets。

测试：

task file {
    FileTree tree = fileTree(dir: 'src/main')
    tree.each {
      File file -> println file.name
    }

    FileTree tree2 = fileTree(dir: '.gradle')
    List list = tree2 as List

    list.each({
      println it
      })
}

输出：

Person.java
resource.xml
C:\temp\quickstart\groovy.gradle\6.0\executionHistory\executionHistory.bin
C:\temp\quickstart\groovy.gradle\6.0\executionHistory\executionHistory.lock
C:\temp\quickstart\groovy.gradle\6.0\fileChanges\last-build.bin
C:\temp\quickstart\groovy.gradle\6.0\fileHashes\fileHashes.bin
C:\temp\quickstart\groovy.gradle\6.0\fileHashes\fileHashes.lock
C:\temp\quickstart\groovy.gradle\6.0\gc.properties
C:\temp\quickstart\groovy.gradle\buildOutputCleanup\buildOutputCleanup.lock
C:\temp\quickstart\groovy.gradle\buildOutputCleanup\cache.properties
C:\temp\quickstart\groovy.gradle\buildOutputCleanup\outputFiles.bin

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