Gradle with Kotlin （一） 安装、DSL、任务、插件

文档

https://gradle.org/guides/#getting-started
https://docs.gradle.org/current/userguide/tutorial_using_tasks.html
https://doc.yonyoucloud.com/doc/wiki/project/GradleUserGuide-Wiki/build_script_basics/task_dependencies.html

安装

• 安装SDKMAN

sudo apt update &&
sudo apt install zip unzip curl sed -y &&
curl -s "https://get.sdkman.io" | bash

按照提示执行

source "$HOME/.sdkman/bin/sdkman-init.sh"

• 安装gradle

sdk install gradle 6.6

创建Gradle项目

gradle init          # 进入交互式界面
gradle init --dsl kotlin    # Kotlin DSL 构建, 将生成build.gradle.kts文件, 而非build.gradle
gradle init --type java-library    # 命令行指定参数,此处指定构建类型为java库

一探Kotlin DSL

由于Kotlin DSL比Groovy DSL更易懂, 我们通过它来研究Gradle
第一次使用Kotlin DSL时, Gradle会自动下载该扩展:

Generating gradle-kotlin-dsl-extensions-6.6.jar

新建一个目录mygradle, 创建文件build.gradle.kts:

log("tasks::class.java => ", tasks::class.java)
log("tasks::class.java.name => ", tasks::class.java.name)

fun log(vararg obj: Any) {
        obj.forEach {
                print("$it ")
        }
        println()
}

执行命令gradle, 看到内置变量tasks是何对象:

~/mygradle$ gradle

> Configure project :
tasks::class.java =>  class org.gradle.api.internal.tasks.DefaultTaskContainer_Decorated
tasks::class.java.name =>  org.gradle.api.internal.tasks.DefaultTaskContainer_Decorated

> Task :help

Welcome to Gradle 6.6.
...

注册任务

tasks.register("hello") {
        doLast {
                println("Hello, Gradle!")
        }
}

tasks.register("hello2", {
        doLast {
                println("Hello, Gradle!")
        }
})

tasks.register("hello3", {
        doLast({
                println("Hello, Gradle!")
        })
})

现在执行gradle hello -quiet或者缩写gradle hello -q, 我们看到打印了Hello, Gradle!, 任务hello2和hello3也是一样, 上面三种写法是等价的.

插件

对于一个空的build.gradle.kts文件, 当我们使用gradle tasks命令时:

$ gradle tasks

> Task :tasks

------------------------------------------------------------
Tasks runnable from root project
------------------------------------------------------------

Build Setup tasks
-----------------
init - Initializes a new Gradle build.
wrapper - Generates Gradle wrapper files.

Help tasks
----------
buildEnvironment - Displays all buildscript dependencies declared in root project 'mygradle'.
components - Displays the components produced by root project 'mygradle'. [incubating]
dependencies - Displays all dependencies declared in root project 'mygradle'.
dependencyInsight - Displays the insight into a specific dependency in root project 'mygradle'.
dependentComponents - Displays the dependent components of components in root project 'mygradle'. [incubating]
help - Displays a help message.
kotlinDslAccessorsReport - Prints the Kotlin code for accessing the currently available project extensions and conventions.
model - Displays the configuration model of root project 'mygradle'. [incubating]
outgoingVariants - Displays the outgoing variants of root project 'mygradle'.
projects - Displays the sub-projects of root project 'mygradle'.
properties - Displays the properties of root project 'mygradle'.
tasks - Displays the tasks runnable from root project 'mygradle'.

To see all tasks and more detail, run gradle tasks --all

当我们添加一个java插件时:

$ cat build.gradle.kts
plugins {
      java
}

$ gradle tasks

> Task :tasks

------------------------------------------------------------
Tasks runnable from root project
------------------------------------------------------------

Build tasks
-----------
assemble - Assembles the outputs of this project.
build - Assembles and tests this project.
buildDependents - Assembles and tests this project and all projects that depend on it.
buildNeeded - Assembles and tests this project and all projects it depends on.
classes - Assembles main classes.
clean - Deletes the build directory.
jar - Assembles a jar archive containing the main classes.
testClasses - Assembles test classes.

Build Setup tasks
-----------------
init - Initializes a new Gradle build.
wrapper - Generates Gradle wrapper files.

Documentation tasks
-------------------
javadoc - Generates Javadoc API documentation for the main source code.

Help tasks
----------
buildEnvironment - Displays all buildscript dependencies declared in root project 'mygradle'.
components - Displays the components produced by root project 'mygradle'. [incubating]
dependencies - Displays all dependencies declared in root project 'mygradle'.
dependencyInsight - Displays the insight into a specific dependency in root project 'mygradle'.
dependentComponents - Displays the dependent components of components in root project 'mygradle'. [incubating]
help - Displays a help message.
kotlinDslAccessorsReport - Prints the Kotlin code for accessing the currently available project extensions and conventions.
model - Displays the configuration model of root project 'mygradle'. [incubating]
outgoingVariants - Displays the outgoing variants of root project 'mygradle'.
projects - Displays the sub-projects of root project 'mygradle'.
properties - Displays the properties of root project 'mygradle'.
tasks - Displays the tasks runnable from root project 'mygradle'.

Verification tasks
------------------
check - Runs all checks.
test - Runs the unit tests.

Rules
-----
Pattern: clean<TaskName>: Cleans the output files of a task.
Pattern: build<ConfigurationName>: Assembles the artifacts of a configuration.
Pattern: upload<ConfigurationName>: Assembles and uploads the artifacts belonging to a configuration.

To see all tasks and more detail, run gradle tasks --all

当添加一个application插件时，多出以下几个任务，用于分发应用程序。

Distribution tasks
------------------
assembleDist - Assembles the main distributions
distTar - Bundles the project as a distribution.
distZip - Bundles the project as a distribution.
installDist - Installs the project as a distribution as-is.

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