IntelliJ中Play子项目无法导入Play-json类问题求助

It looks like your core submodule is missing the Play JSON dependency, which is why you can't import play.api.libs.json.Json. Here's how to fix this step by step:

1. Add Play JSON to Your Common Dependencies #

First, update your project/Common.scala to include the Play JSON dependency definition. Make sure the version matches your Play framework version (since you're using 0.13.0-play26 for ReactiveMongo, stick with Play 2.6.x versions):

import sbt._
import sbt.Keys._
object Common {
  val settings = Seq(
    organization := "com.company.app",
    scalaVersion := "2.12.5"
  )
  val dependencies = new {
    val macwireVersion = "2.3.0"
    val reactiveMongoVersion = "0.13.0-play26"
    val slickVersion = "3.0.3"
    val postgresVersion = "42.2.2"
    val scalatestPlayVersion = "3.1.2" // Example version matching Play 2.6
    // Add Play JSON dependency
    val playJsonVersion = "2.6.15"
    val playJson = "com.typesafe.play" %% "play-json" % playJsonVersion
  }
}

2. Include the Dependency in Your Core Subproject #

Next, modify your main build.sbt to add the Play JSON dependency to your core submodule. Assuming your core subproject is defined like this:

lazy val core = (project in file("core"))
 .settings(Common.settings)
 .settings(
    libraryDependencies ++= Seq(
      Common.dependencies.playJson,
      // Add other dependencies your core module needs here
      Common.dependencies.macwire,
      Common.dependencies.slick
    )
  )

3. Verify Compatibility and Refresh #

• Double-check that the Play JSON version you chose is compatible with Scala 2.12.5 (Play 2.6.x fully supports Scala 2.12).
• Run sbt clean compile in your terminal to rebuild the project, or refresh the project in your IDE to pick up the new dependencies.

Why This Works #

The Play JSON library is a standalone artifact separate from the full Play framework. Even if your core module isn't a complete Play application, you can still include just the JSON parsing functionality by adding this specific dependency.

内容的提问来源于stack exchange，提问作者raul782