无法为扩展"应用程序"设置未知属性'mainClass'

Question

我在我的项目中使用的是 Gradle 6.1 版。

该项目的build.gradle如下：

plugins {
id 'application'
}
application {
mainClass = 'com.mytestproject.Main'
}
java {
sourceCompatibility = JavaVersion.VERSION_1_8
targetCompatibility = JavaVersion.VERSION_1_8
}
group 'com.mytestproject'
version '1.0-SNAPSHOT'
repositories {
mavenCentral()
}
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.12'
}

但是当我./gradlew assemble运行此命令时，它给了我以下错误：

./gradlew assemble
FAILURE: Build failed with an exception.
* Where:
Build file '/com/myproject/build.gradle' line: 6
* What went wrong:
A problem occurred evaluating root project 'JavaTestProject'.
> Could not set unknown property 'mainClass' for extension 'application' of type org.gradle.api.plugins.internal.DefaultJavaApplication.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 484ms

Answer 1

将build.gradle修改为：

apply plugin: "application"
mainClassName = "com.mytestproject.Main"
sourceCompatibility = 1.8
targetCompatibility = 1.8
group 'com.mytestproject'
version '1.0-SNAPSHOT'
repositories {
mavenCentral()
}
dependencies {
testCompile group: 'junit', name: 'junit', version: '4.12'
}

运行此通信：./gradlew build

Answer 2

你可以试试这个(基于源代码(：

application {
setMainClassName("some.package.Main")
}

Answer 3

实际上只是将application块修改为

application {
mainClassName = 'com.mytestproject.Main'
}

做同样的事情。

问题似乎是org.gradle.api.plugins.internal.DefaultJavaApplication类上曾经有一个mainClass属性，但后来它被重命名为mainClassName，使以前的教程无效。

Answer 4

6.4 中引入了弃用。它来自：

application {
mainClassName = "com.foo.bar.FooBar"
}

自：

application {
mainClass.set("com.foo.bar.FooBar")
}

文档：

https://docs.gradle.org/current/javadoc/org/gradle/api/plugins/JavaApplication.html#getMainClassName--