如何将 Gradle 项目中 Kotlin 的字节码版本设置为 Java 8? [英] How to set up Kotlin's byte code version in Gradle project to Java 8?

问题描述

在 Kotlin 项目中，什么是正确的 Gradle 脚本以确保我的类将被编译为字节码 ver 52 (Java 8)?

In Kotlin project, what is a proper Gradle script to make sure my classes will be compiled to byte code ver 52 (Java 8)?

出于某种原因，即使我设置了源和目标兼容性，我的类还是编译为 ver 50 (Java 6).至少这是我在构建项目后从目录 build/classes/... 打开文件时 Idea 向我显示的内容.

For some reason my classes are compiled as ver 50 (Java 6) even though I set up source and target compatibility. At least this is what Idea shows me when I open file from directory build/classes/... after building the project.

我目前的设置是这样的.

My current set up looks like this.

buildscript {
    ext {
        kotlinVersion = '1.0.5-2'
        springBootVersion = '1.4.2.RELEASE'
    }
    repositories { mavenCentral() }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
    }
}

apply plugin: 'kotlin'
apply plugin: 'org.springframework.boot'

tasks.withType(JavaCompile) {
    sourceCompatibility = JavaVersion.VERSION_1_8
    targetCompatibility = JavaVersion.VERSION_1_8
}

## I also tried this and it hasn't helped
#sourceCompatibility = 1.8
#targetCompatibility = 1.8

repositories { mavenCentral() }

dependencies {
    compile("org.jetbrains.kotlin:kotlin-stdlib:${kotlinVersion}")
    compile('org.springframework.cloud:spring-cloud-starter-stream-rabbit')
}

dependencyManagement { imports { mavenBom "org.springframework.cloud:spring-cloud-dependencies:Camden.SR2" } }

推荐答案

正如 Mark 在 Debop 的回答中指出的那样，您必须同时配置 compileKotlin 和 compileTestKotlin.你可以这样做而无需重复:

As Mark pointed out on Debop's answer, you have to configure both compileKotlin and compileTestKotlin. You can do it without duplication this way:

tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).all {
  kotlinOptions {
    jvmTarget = "1.8"
  }
}

对于纯 Kotlin 项目，我认为选项 sourceCompatibility 和 targetCompatibility 没有任何作用，因此您可以删除它们.

For a pure Kotlin project, I don't think the options sourceCompatibility and targetCompatibility do anything, so you may be able to remove them.

参考:https://kotlinlang.org/docs/reference/using-gradle.html#compiler-options

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