无法在多平台项目中使用 kotlinx.serialization

Question

我正在尝试在多平台 (JVM/JS) 项目中使用 kotlinx.serialization。

当我在公共模块中的某些 class 中向某些数据 class 添加 @Serializable 注释时：

@Serializable
data class User(
    val user: String
)

构建成功，没有错误，但看起来 encoders/decoders 没有生成。

在 build/generated-src 中，我没有看到任何提供 encodeToString 扩展功能的相关 kotlin 文件，当我尝试使用类似的东西时：

JSON.encodeToString(User(login = "X"))

我收到未解决的引用错误：

Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
public inline fun <reified T> StringFormat.encodeToString(value: TypeVariable(T)): String defined in kotlinx.serialization

如能帮助解决此问题，我们将不胜感激。提前致谢。

我的build.gradle.kts:

import org.jetbrains.kotlin.gradle.targets.js.nodejs.NodeJsRootPlugin
import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpack
import org.jetbrains.kotlin.gradle.targets.js.webpack.KotlinWebpackConfig

/* buildscript {
    dependencies {
        val kotlinVersion: String by System.getProperties()
        classpath(kotlin("serialization", version = kotlinVersion))
    }
} */

plugins {
    val kotlinVersion: String by System.getProperties()
    kotlin("multiplatform") version kotlinVersion
    id("kotlinx-serialization") version kotlinVersion
    val kvisionVersion: String by System.getProperties()
    id("kvision") version kvisionVersion
}


version = "1.0.0-SNAPSHOT"
group = "tech.lorefnon"

repositories {
    mavenCentral()
    jcenter()
    maven { url = uri("https://dl.bintray.com/kotlin/kotlin-eap") }
    maven { url = uri("https://kotlin.bintray.com/kotlinx") }
    maven { url = uri("https://dl.bintray.com/kotlin/kotlin-js-wrappers") }
    maven { url = uri("https://dl.bintray.com/rjaros/kotlin") }
    maven { url = uri("https://repo.spring.io/milestone") }
    maven { url = uri("https://oss.sonatype.org/content/repositories/snapshots") }
    mavenLocal()
}

// Versions
val kotlinVersion: String by System.getProperties()
val kvisionVersion: String by System.getProperties()
val ktorVersion: String by project
val logbackVersion: String by project
val commonsCodecVersion: String by project

val webDir = file("src/frontendMain/web")
val mainClassName = "io.ktor.server.netty.EngineMain"

kotlin {
    jvm("backend") {
        compilations.all {
            kotlinOptions {
                jvmTarget = "1.8"
                freeCompilerArgs = listOf("-Xjsr305=strict")
            }
        }
    }
    js("frontend") {
        browser {
            runTask {
                outputFileName = "main.bundle.js"
                sourceMaps = false
                devServer = KotlinWebpackConfig.DevServer(
                    open = false,
                    port = 3000,
                    proxy = mapOf(
                        "/kv/*" to "http://localhost:8080",
                        "/login" to "http://localhost:8080",
                        "/logout" to "http://localhost:8080",
                        "/kvws/*" to mapOf("target" to "ws://localhost:8080", "ws" to true)
                    ),
                    contentBase = listOf("$buildDir/processedResources/frontend/main")
                )
            }
            webpackTask {
                outputFileName = "main.bundle.js"
            }
            testTask {
                useKarma {
                    useChromeHeadless()
                }
            }
        }
        binaries.executable()
    }
    sourceSets {
        val commonMain by getting {
            dependencies {
                implementation(kotlin("stdlib-common"))
                api("pl.treksoft:kvision-server-ktor:$kvisionVersion")
                implementation("org.jetbrains.kotlinx:kotlinx-collections-immutable:0.3.3")
                implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.0.1")
            }
            kotlin.srcDir("build/generated-src/common")
            kotlin.srcDir("src/commonMain/kotlin")
        }
        val commonTest by getting {
            dependencies {
                implementation(kotlin("test-common"))
                implementation(kotlin("test-annotations-common"))
            }
        }
        val backendMain by getting {
            dependencies {
                implementation(kotlin("stdlib-jdk8"))
                implementation(kotlin("reflect"))
                implementation("com.auth0:java-jwt:3.11.0")
                implementation("io.ktor:ktor-server-netty:$ktorVersion")
                implementation("io.ktor:ktor-auth:$ktorVersion")
                implementation("io.ktor:ktor-auth-jwt:$ktorVersion")
                implementation("ch.qos.logback:logback-classic:$logbackVersion")
                implementation("commons-codec:commons-codec:$commonsCodecVersion")
                implementation("org.redisson:redisson:3.14.0")
                implementation("org.jetbrains.kotlinx:kotlinx-coroutines-jdk8:1.4.2")
            }
        }
        val backendTest by getting {
            dependencies {
                implementation(kotlin("test"))
                implementation(kotlin("test-junit"))
            }
        }
        val frontendMain by getting {
            resources.srcDir(webDir)
            dependencies {
                implementation("pl.treksoft:kvision:$kvisionVersion")
                implementation("pl.treksoft:kvision-redux:${kvisionVersion}")
                implementation("pl.treksoft:kvision-bootstrap:$kvisionVersion")
                implementation("pl.treksoft:kvision-bootstrap-select:$kvisionVersion")
                implementation("pl.treksoft:kvision-datacontainer:$kvisionVersion")
                implementation("pl.treksoft:kvision-bootstrap-dialog:$kvisionVersion")
                implementation("pl.treksoft:kvision-fontawesome:$kvisionVersion")
                implementation("pl.treksoft:kvision-i18n:$kvisionVersion")
                implementation(npm("redux-logger", "3.0.6"))
            }
            kotlin.srcDir("build/generated-src/frontend")
        }
        val frontendTest by getting {
            dependencies {
                implementation(kotlin("test-js"))
                implementation("pl.treksoft:kvision-testutils:$kvisionVersion:tests")
            }
        }
    }
}

fun getNodeJsBinaryExecutable(): String {
    val nodeDir = NodeJsRootPlugin.apply(project).nodeJsSetupTaskProvider.get().destination
    val isWindows = System.getProperty("os.name").toLowerCase().contains("windows")
    val nodeBinDir = if (isWindows) nodeDir else nodeDir.resolve("bin")
    val command = NodeJsRootPlugin.apply(project).nodeCommand
    val finalCommand = if (isWindows && command == "node") "node.exe" else command
    return nodeBinDir.resolve(finalCommand).absolutePath
}


afterEvaluate {
    tasks {
        getByName("frontendProcessResources", Copy::class) {
            dependsOn("compileKotlinFrontend")
            exclude("**/*.pot")
            doLast("Convert PO to JSON") {
                destinationDir.walkTopDown().filter {
                    it.isFile && it.extension == "po"
                }.forEach {
                    exec {
                        executable = getNodeJsBinaryExecutable()
                        args(
                            "$buildDir/js/node_modules/gettext.js/bin/po2json",
                            it.absolutePath,
                            "${it.parent}/${it.nameWithoutExtension}.json"
                        )
                        println("Converted ${it.name} to ${it.nameWithoutExtension}.json")
                    }
                    it.delete()
                }
            }
        }
        create("frontendArchive", Jar::class).apply {
            dependsOn("frontendBrowserProductionWebpack")
            group = "package"
            archiveAppendix.set("frontend")
            val distribution =
                project.tasks.getByName("frontendBrowserProductionWebpack", KotlinWebpack::class).destinationDirectory!!
            from(distribution) {
                include("*.*")
            }
            from(webDir)
            duplicatesStrategy = DuplicatesStrategy.EXCLUDE
            into("/assets")
            inputs.files(distribution, webDir)
            outputs.file(archiveFile)
            manifest {
                attributes(
                    mapOf(
                        "Implementation-Title" to rootProject.name,
                        "Implementation-Group" to rootProject.group,
                        "Implementation-Version" to rootProject.version,
                        "Timestamp" to System.currentTimeMillis()
                    )
                )
            }
        }
        getByName("backendProcessResources", Copy::class) {
            duplicatesStrategy = DuplicatesStrategy.EXCLUDE
        }
        getByName("backendJar").group = "package"
        create("jar", Jar::class).apply {
            dependsOn("frontendArchive", "backendJar")
            group = "package"
            manifest {
                attributes(
                    mapOf(
                        "Implementation-Title" to rootProject.name,
                        "Implementation-Group" to rootProject.group,
                        "Implementation-Version" to rootProject.version,
                        "Timestamp" to System.currentTimeMillis(),
                        "Main-Class" to mainClassName
                    )
                )
            }
            val dependencies = configurations["backendRuntimeClasspath"].filter { it.name.endsWith(".jar") } +
                    project.tasks["backendJar"].outputs.files +
                    project.tasks["frontendArchive"].outputs.files
            dependencies.forEach {
                if (it.isDirectory) from(it) else from(zipTree(it))
            }
            exclude("META-INF/*.RSA", "META-INF/*.SF", "META-INF/*.DSA")
            inputs.files(dependencies)
            outputs.file(archiveFile)
            duplicatesStrategy = DuplicatesStrategy.EXCLUDE
        }
        create("backendRun", JavaExec::class) {
            dependsOn("compileKotlinBackend")
            group = "run"
            main = mainClassName
            classpath =
                configurations["backendRuntimeClasspath"] + project.tasks["compileKotlinBackend"].outputs.files +
                        project.tasks["backendProcessResources"].outputs.files
            workingDir = buildDir
        }
        getByName("compileKotlinBackend") {
            dependsOn("compileKotlinMetadata")
        }
        getByName("compileKotlinFrontend") {
            dependsOn("compileKotlinMetadata")
        }
    }
}

和gradle.properties：

javaVersion=1.8
#Plugins
systemProp.kotlinVersion=1.4.20
systemProp.serializationVersion=1.0.1
#Dependencies
systemProp.kvisionVersion=3.17.2
ktorVersion=1.4.3
commonsCodecVersion=1.10
logbackVersion=1.2.3

kotlin.mpp.stability.nowarn=true
kotlin.js.compiler=legacy
org.gradle.jvmargs=-Xmx2g

和settings.gradle.kts：

pluginManagement {
    repositories {
        mavenCentral()
        jcenter()
        maven { url = uri("https://plugins.gradle.org/m2/") }
        maven { url = uri("https://dl.bintray.com/kotlin/kotlin-eap") }
        maven { url = uri("https://kotlin.bintray.com/kotlinx") }
        maven { url = uri("https://dl.bintray.com/rjaros/kotlin") }
        mavenLocal()
    }
    resolutionStrategy {
        eachPlugin {
            when {
                requested.id.id == "kotlinx-serialization" -> useModule("org.jetbrains.kotlin:kotlin-serialization:${requested.version}")
                requested.id.id == "kvision" -> useModule("pl.treksoft:kvision-gradle-plugin:${requested.version}")
            }
        }
    }
}
rootProject.name = "test"

Answer 1

我经常遇到同样的问题。你只需要添加 import:

import kotlinx.serialization.encodeToString

您可能不想手动添加导入，我通常开始输入 encodeToStr，然后等待建议出现并选择 encodeToString(value: T)，这将添加所需的导入。

我认为这是一个错误，IDE 没有给您建议导入，而是给我们这个错误。

无法在多平台项目中使用 kotlinx.serialization

Unable to use kotlinx.serialization in multiplatform project

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