如何在命令行运行交互式Kotlin JVM程序并解决主类缺失问题

我的Kotlin JVM应用在IntelliJ内置Shell中可正常交互运行，但通过命令行运行或分发时出现错误，程序仅使用readln()函数。

代码与构建配置 #

Kotlin主代码 #

package com.xingpeds

fun main() {
    val name = readln()
    println("Hello, " + name + "!")
}

Gradle构建文件 #

plugins {
    kotlin("jvm") version "2.0.20"
    application
}
application {
    mainClass.set("MainKt")
}
group = "com.xingpeds"
version = "1.0-SNAPSHOT"

repositories {
    mavenCentral()
}

dependencies {
    testImplementation(kotlin("test"))
}

tasks.test {
    useJUnitPlatform()
}
kotlin {
    jvmToolchain(19)
}

错误信息 #

执行./gradlew clean run时输出错误：

euclid@kyles-MBP-3 ~/D/democli (main)> ./gradlew clean run

> Task :run FAILED
Error: Could not find or load main class MainKt
Caused by: java.lang.ClassNotFoundException: MainKt

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':run'.
> Process 'command '/Users/euclid/Library/Java/JavaVirtualMachines/corretto-19.0.2/Contents/Home/bin/java'' finished with non-zero exit value 1

* 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 545ms
3 actionable tasks: 3 executed

运行构建生成的脚本build/scripts/democli时同样报错：

euclid@kyles-MBP-3 ~/D/democli (main)> build/scripts/democli
Error: Could not find or load main class MainKt
Caused by: java.lang.ClassNotFoundException: MainKt

解决方法 #

核心问题：主类配置错误 #

你的main函数位于com.xingpeds包下，Kotlin会将顶层函数编译为包名.MainKt格式的类，因此Gradle中配置的主类必须包含完整包路径，而非仅MainKt。

步骤1：修正Gradle主类配置 #

修改构建文件中的application块，将mainClass设置为完整类名：

application {
    mainClass.set("com.xingpeds.MainKt")
}

步骤2：重新运行或构建 #

• 直接运行程序：执行./gradlew clean run，此时程序可正常读取命令行输入
• 构建可分发的本地脚本：执行./gradlew clean installDist，生成的脚本位于build/install/[你的项目名]/bin/目录下，直接运行该脚本即可

可选：构建可独立运行的Jar包 #

如果需要分发单个可运行Jar包，可使用shadowJar插件构建包含所有依赖的fat jar：

1. 在构建文件的plugins块中添加插件：

plugins {
    kotlin("jvm") version "2.0.20"
    application
    id("com.github.johnrengelman.shadow") version "8.1.1"
}

2. 执行构建命令：./gradlew shadowJar
3. 运行生成的Jar包：java -jar build/libs/[项目名]-1.0-SNAPSHOT-all.jar

内容的提问来源于stack exchange，提问作者Kyle M