Gradle with Kotlin (二) 项目、Java项目、父子、同级共享代码

在 settings.gradle 中使用 include 包含项目

$ tree
.
├── a
│   └── build.gradle.kts
├── build.gradle.kts
└── settings.gradle

1 directory, 3 files

$ cat build.gradle.kts
tasks.register("hi") {
        doLast {
                println("Father")
        }
}

$ cat settings.gradle.kts
rootProject.name = "mygradle"
include("a")

$ cat a/build.gradle.kts
tasks.register("hi") {
        doLast {
                println("Son")
        }
}

$ gradle hi # 在父项目执行hi任务
Starting a Gradle Daemon (subsequent builds will be faster)

> Task :hi
Father

> Task :a:hi
Son

BUILD SUCCESSFUL in 5s
2 actionable tasks: 2 executed

在父项目执行hi任务时，子项目也相继执行了hi任务。即同名任务全部执行。
如果在父项目中执行只有子项目中存在任务，也是可以的，不会出现找不到任务的错误。

回到Java

Gradle天生为Java而生，我们来看看如何使用gradle命令创建一个Gradle项目

现在得到这样一个目录结构：

接下来新建一个目录：liba，使用gradle init创建一个library：

# 查看build.gradle.kts
githmb@MyServer:~/mygradle/liba$ cat build.gradle.kts
plugins {
    // Apply the java-library plugin to add support for Java Library
    `java-library`
}

repositories {
    // Use jcenter for resolving dependencies.
    // You can declare any Maven/Ivy/file repository here.
    jcenter()
}

dependencies {
    // This dependency is exported to consumers, that is to say found on their compile classpath.
    api("org.apache.commons:commons-math3:3.6.1")

    // This dependency is used internally, and not exposed to consumers on their own compile classpath.
    implementation("com.google.guava:guava:29.0-jre")

    // Use JUnit test framework
    testImplementation("junit:junit:4.13")
}

# 源码：src/main/java/com/liba/Library.java
githmb@MyServer:~/mygradle/liba$ cat src/main/java/com/liba/Library.java
/*
 * This Java source file was generated by the Gradle 'init' task.
 */
package com.liba;

public class Library {
    public boolean someLibraryMethod() {
        return true;
    }
}

# 在父项目中settings.gradle.kts中包含liba项目
githmb@MyServer:~/mygradle$ cat settings.gradle.kts
/*
 * This file was generated by the Gradle 'init' task.
 *
 * The settings file is used to specify which projects to include in your build.
 *
 * Detailed information about configuring a multi-project build in Gradle can be found
 * in the user manual at https://docs.gradle.org/6.6/userguide/multi_project_builds.html
 */

rootProject.name = "mygradle"
include("liba")

# 在父项目中build.gradle.kts中添加liba项目依赖
dependencies {
    // This dependency is used by the application.
    implementation("com.google.guava:guava:29.0-jre")
    implementation(project("liba"))

    // Use JUnit test framework
    testImplementation("junit:junit:4.13")
}

# 使用liba类
githmb@MyServer:~/mygradle$ cat src/main/java/com/mygradle/App.java
/*
 * This Java source file was generated by the Gradle 'init' task.
 */
package com.mygradle;

public class App {
    public String getGreeting() {
        return "Hello world.";
    }

    public static void main(String[] args) {
        System.out.println(new App().getGreeting());
        com.liba.Library liba = new com.liba.Library();
        System.out.println(liba.someLibraryMethod());
    }
}

# 运行
githmb@MyServer:~/mygradle$ gradle run

> Task :run
Hello world.
true

BUILD SUCCESSFUL in 795ms
4 actionable tasks: 1 executed, 3 up-to-date

同一级项目的代码共享

一般来说父级单独向子级获取代码就可以了，但是这会遇到重复依赖的问题，试问如何解决？

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