How to convert a kotlin source file to a java source file

问题

I have a Kotlin source file, but I want to translate it to Java.

How can I convert Kotlin to Java source?

回答1:

As @Vadzim said, in IntelliJ or Android Studio, you just have to do the following to get java code from kotlin:

Menu > Tools > Kotlin > Show Kotlin Bytecode
Click on the Decompile button
Copy the java code

Update:

With a recent version (1.2+) of the Kotlin plugin you also can directly do Menu > Tools > Kotlin -> Decompile Kotlin to Java.

回答2:

You can compile Kotlin to bytecode, then use a Java disassembler.

The decompiling may be done inside IntelliJ Idea, or using FernFlower https://github.com/fesh0r/fernflower (thanks @Jire)

There was no automated tool as I checked a couple months ago (and no plans for one AFAIK)

回答3:

you can go to Tools > Kotlin > Show kotlin bytecode

回答4:

I compile Kotlin to byte code and then de-compile that to Java. I compile with the Kotlin compiler and de-compile with cfr.

My project is here.

This allows me to compile this:

package functionsiiiandiiilambdas.functions.p01tailiiirecursive

tailrec fun findFixPoint(x: Double = 1.0): Double =
        if (x == Math.cos(x)) x else findFixPoint(Math.cos(x))

To this:

package functionsiiiandiiilambdas.functions.p01tailiiirecursive;

public final class ExampleKt {
  public static final double findFixPoint(double x) {
    while (x != Math.cos(x)) {
      x = Math.cos(x);
    }
    return x;
  }

  public static /* bridge */ /* synthetic */ double findFixPoint$default(
      double d, int n, Object object) {
    if ((n & 1) != 0) {
      d = 1.0;
    }
    return ExampleKt.findFixPoint(d);
  }
}

回答5:

To convert a Kotlin source file to a Java source file you need to (when you in Android Studio):

Press Cmd-Shift-A on a Mac, or press Ctrl-Shift-A on a Windows machine.
Type the action you're looking for: Kotlin Bytecode and choose Show Kotlin Bytecode from menu.

Press Decompile button on the top of Kotlin Bytecode panel.

Now you get a Decompiled Java file along with Kotlin file in a adjacent tab:

Hope this helps.

回答6:

As @louis-cad mentioned "Kotlin source -> Java's byte code -> Java source" is the only solution so far.

But I would like to mention the way, which I prefer: using Jadx decompiler for Android.

It allows to see the generates code for closures and, as for me, resulting code is "cleaner" then one from IntelliJ IDEA decompiler.

Normally when I need to see Java source code of any Kotlin class I do:

Generate apk: ./gradlew assembleDebug
Open apk using Jadx GUI: jadx-gui ./app/build/outputs/apk/debug/app-debug.apk

In this GUI basic IDE functionality works: class search, click to go declaration. etc.

Also all the source code could be saved and then viewed using other tools like IntelliJ IDEA.

回答7:

open kotlin file in android studio
go to tools -> kotlin ->kotlin bytecode
in the new window that open beside your kotlin file , click the decompile button . it will create java equivalent of your kotlin file .

回答8:

I can't believe nobody has mentioned Local History yet: by default, IDEA will keep a history of changes to a file.

To get your files back exactly the way they were before you converted them to Kotlin:

For each file you want to revert back:

Open Find Action (Command-Shift-A on Mac)
Search for "Local History"
Press Enter twice (once to accept "Local History" in the search results, and then once more to select "Show History" in the Local History menu)
Find "Convert files from Java to Kotlin" in the list on the left hand side
Right click on it, and select "Revert"

This might not work if you did it months ago (because Local History is not a VCS), and it does not, for instance, re-create any methods you added using Kotlin, but it worked for me.

来源：https://stackoverflow.com/questions/34957430/how-to-convert-a-kotlin-source-file-to-a-java-source-file

标签

java

kotlin

code-conversion