CMake 找不到 JNI

Question

我创建了一个支持 C++ 的新 Android Studio 项目，但没有向其中添加任何内容。该项目使用 CMake 构建、编译和运行。然后我将以下两行代码添加到文件底部的CMakeLists.txt 中，我得到了一个 CMake 构建错误。

find_package(Java COMPONENTS Development)       # Line 47
find_package(JNI REQUIRED)                      # Line 48

这是我在构建项目时遇到的错误

-- Found Java: /usr/lib/jvm/java-10-oracle/bin/java (found version "10.0.1") found components:  Development 
-- Configuring incomplete, errors occurred!
CMake Error at /home/xxxxx/Android/Sdk/cmake/3.6.4111459/share/cmake-3.6/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find JNI (missing: JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY
See also "/home/xxxxx/AndroidStudioProjects/MyApplication/app/.externalNativeBuild/cmake/release/x86_64/CMakeFiles/CMakeOutput.log".
  JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH)
Call Stack (most recent call first):
  /home/xxxxxx/Android/Sdk/cmake/3.6.4111459/share/cmake-3.6/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  /home/xxxxxx/Android/Sdk/cmake/3.6.4111459/share/cmake-3.6/Modules/FindJNI.cmake:314 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:48 (find_package)
External native generate JSON release: JSON generation completed with problems

CMake 在从命令行调用时运行，但由于某种原因在 Android Studio 中失败，我不知道为什么。

编辑 1

这是CMakeOutput.log 文件

编辑 2

这就是CMakeLists.txt 文件中的全部内容。它使用命令 cmake 在 cmd 中编译。

cmake_minimum_required(VERSION 3.4.1)

find_package(Java COMPONENTS Development)
find_package(JNI REQUIRED)

这是 cmd 输出

    E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\build>cmake ..
-- Configuring done
-- Generating done
-- Build files have been written to: E:/Users/xxxxx/AndroidStudioProjects/MyApplication/app/build

当我尝试使用 gradle 在 Android Studio 中添加它时，我在 Windows 10 pro 64 位上收到以下错误

Microsoft Windows [Version 10.0.17134.112]
(c) 2018 Microsoft Corporation. All rights reserved.

E:\Users\xxxxx\AndroidStudioProjects\MyApplication>gradlew build --stacktrace

> Task :app:generateJsonModelDebug 
External native generate JSON debug: starting JSON generation
External native generate JSON debug: using platform version 24 for ABI ARMEABI_V7A and min SDK version 24
External native generate JSON debug: noticing that build file 'E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\CMakeLists.txt' is out of date with respect to E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\.extern
alNativeBuild\cmake\debug\armeabi-v7a\android_gradle_build.json
External native generate JSON debug: rebuilding JSON E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\.externalNativeBuild\cmake\debug\armeabi-v7a\android_gradle_build.json due to:
External native generate JSON debug: - a dependent build file changed
External native generate JSON debug: keeping json folder 'E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\.externalNativeBuild\cmake\debug\armeabi-v7a' but regenerating project
External native generate JSON debug: executing cmake Executable : E:\Android\SDK\cmake\3.6.4111459\bin\cmake.exe
arguments :
-HE:\Users\xxxxx\AndroidStudioProjects\MyApplication\app
-BE:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\.externalNativeBuild\cmake\debug\armeabi-v7a
-DANDROID_ABI=armeabi-v7a
-DANDROID_PLATFORM=android-24
-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=E:\Users\xxxxx\AndroidStudioProjects\MyApplication\app\build\intermediates\cmake\debug\obj\armeabi-v7a
-DCMAKE_BUILD_TYPE=Debug
-DANDROID_NDK=E:\Android\SDK\ndk-bundle
-DCMAKE_CXX_FLAGS=
-DCMAKE_TOOLCHAIN_FILE=E:\Android\SDK\ndk-bundle\build\cmake\android.toolchain.cmake
-DCMAKE_MAKE_PROGRAM=E:\Android\SDK\cmake\3.6.4111459\bin\ninja.exe
-GAndroid Gradle - Ninja
jvmArgs :


CMake Error at E:/Android/SDK/cmake/3.6.4111459/share/cmake-3.6/Modules/FindPackageHandleStandardArgs.cmake:148 (message):
  Could NOT find JNI (missing: JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY
  JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH)
Call Stack (most recent call first):
  E:/Android/SDK/cmake/3.6.4111459/share/cmake-3.6/Modules/FindPackageHandleStandardArgs.cmake:388 (_FPHSA_FAILURE_MESSAGE)
  E:/Android/SDK/cmake/3.6.4111459/share/cmake-3.6/Modules/FindJNI.cmake:314 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  CMakeLists.txt:4 (find_package)
-- Configuring incomplete, errors occurred!
See also "E:/Users/xxxxx/AndroidStudioProjects/MyApplication/app/.externalNativeBuild/cmake/debug/armeabi-v7a/CMakeFiles/CMakeOutput.log".

Answer 1

Could NOT find JNI (missing: JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY

解决了

sudo apt-get install -y openjdk-8-jdk
sudo apt-get install -y default-jdk
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64

Answer 2

正如与 Android 捆绑的 CMake 版本试图告诉您的那样，它找不到 JNI 包，因为缺少某些部分：

缺少：JAVA_AWT_LIBRARY JAVA_JVM_LIBRARY JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH

查看 FindJNI (https://cmake.org/cmake/help/latest/module/FindJNI.html) 的文档，这些变量设置为 Android 版本的 JNI 未附带的库和标头的位置（毫不奇怪，例如，Android 不包含 AWT 库）。 在运行find_package(JNI REQUIRED) 时，FindJNI 代码会检查这些变量是否已设置，如果未设置，则会发出错误。

一种解决方法是在调用find_package之前自己设置这些变量：

# We are only interested in finding jni.h: we do not care about extended JVM
# functionality or the AWT library.
set(JAVA_AWT_LIBRARY NotNeeded)
set(JAVA_JVM_LIBRARY NotNeeded)
set(JAVA_INCLUDE_PATH2 NotNeeded)
set(JAVA_AWT_INCLUDE_PATH NotNeeded)
find_package(JNI REQUIRED)

但请注意，您的代码将只能使用 jni.h 及其功能：如果它尝试访问 JNI 包的任何其他部分，它将失败（可能在编译时) 因为本质上，您已经欺骗 CMake 以为找到了整个包，而实际上只有一部分存在于 Android 设置中。

Answer 3

我找到了适合我的解决方案：

cmake_minimum_required(VERSION 3.10)
project("ktaglib")

set(JAVA_AWT_LIBRARY "$ENV{JAVA_HOME}/lib/libjawt.so")
set(JAVA_JVM_LIBRARY "$ENV{JAVA_HOME}/lib/server/libjvm.so")


set(JAVA_INCLUDE_PATH "$ENV{JAVA_HOME}/include")
set(JAVA_INCLUDE_PATH2 "$ENV{JAVA_HOME}/include/linux")
set(JAVA_AWT_INCLUDE_PATH "$ENV{JAVA_HOME}/include")

find_package(JNI REQUIRED)

您必须在环境变量中的 JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64" 之前设置，例如

更多信息：https://github.com/dockcross/dockcross/issues/576

Answer 4

在 alpine:edge docker 镜像上也是如此，使用以下方法修复：

ENV JAVA_HOME=/usr/lib/jvm/java-1.8-openjdk
RUN apk add --no-cache openjdk8

参考：https://pkgs.alpinelinux.org/contents?branch=edge&name=openjdk8&arch=x86_64&repo=community