cmake find_package(JNI)在Ubuntu 12.04 amd64中不起作用

Question

我在Ubuntu12.04 amd64上使用cmake 2.8.7。我的系统中安装的OpenJDK JRE组件如下所示：

$ sudo dpkg --list | grep jdk
openjdk-6-jre   6b27-1.12.5-0ubuntu0.12.04.1   OpenJDK Java runtime, using Hotspot JIT
openjdk-6-jre-headless   6b27-1.12.5-0ubuntu0.12.04.1   OpenJDK Java runtime, using Hotspot JIT (headless)
openjdk-6-jre-lib   6b27-1.12.5-0ubuntu0.12.04.1   OpenJDK Java runtime (architecture independent libraries)

但是，我没有使用OpenJDK JRE组件。我在"/usr/lib/jvm/jdk1.7.0_25“中手动安装了Oracle Java 7 JDK，并使用"update-alternatives”将" Java“指向我安装的Oracle Java 7 JDK。我没有设置任何"JAVA_HOME“、"JAVA_BIN”、"CLASSPATH“环境变量，手动安装的Oracle Java7JDK在Eclipse4.3中似乎工作正常。

问题是，当我在cmake中使用"find_package( JNI )“并使用"message()”函数来显示JNI变量时，我得到了以下结果：

Could NOT find JNI (missing:  JAVA_INCLUDE_PATH JAVA_INCLUDE_PATH2 JAVA_AWT_INCLUDE_PATH) 
JNI_FOUND = FALSE
JNI_LIBRARIES = /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/libjawt.so;/usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/libjvm.so
JAVA_INCLUDE_PATH = JAVA_INCLUDE_PATH-NOTFOUND
JAVA_INCLUDE_PATH2 = JAVA_INCLUDE_PATH2-NOTFOUND
JAVA_AWT_INCLUDE_PATH = JAVA_AWT_INCLUDE_PATH-NOTFOUND
JAVA_JVM_LIBRARY = /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/server/libjvm.so
JAVA_AWT_LIBRARY = /usr/lib/jvm/java-6-openjdk/jre/lib/amd64/libjawt.so
JNI_INCLUDE_DIRS = JAVA_INCLUDE_PATH-NOTFOUND;JAVA_INCLUDE_PATH2-NOTFOUND;JAVA_AWT_INCLUDE_PATH-NOTFOUND

"find_package(JNI)“似乎可以找到一些与OpenJDK JRE相关的Java组件，但无法找到"update-alternatives”所指向的当前OracleJava7JDK组件。

我想知道"FindJNI.cmake“文件中是否有任何bug，以及我在OracleJava7JDK设置中遗漏了什么，以便cmake "find_package(JNI)”能够正常工作。

谢谢你的建议。

Answer 1

您可以手动修改FindJNI.cmake以帮助它找到已安装的JDK。请看下面的要点：

https://gist.github.com/emchristiansen/6845954

遗憾的是，这个脚本没有更新，但也许并不令人惊讶，因为CMake是一场灾难。

编辑:更简单的解决方案是正确设置JAVA_HOME。在安装了OpenJDK 7的情况下，我使用以下命令进行设置：

export JAVA_HOME=/usr/lib/jvm/java-7-openjdk-amd64

Answer 2

如果您的系统上安装了oracle jdk 7，就像我这样，在构建opencv时可能会遇到问题。为了解决这些问题，我不得不编辑/usr/share/cmake-2.8/Modules/FindJNI.cmake文件。在这个文件中，我注释掉了引用openjdk和default的行，并添加了oracle jdk 7的引用，如下所示。

JAVA_APPEND_LIBRARY_DIRECTORIES(JAVA_AWT_LIBRARY_DIRECTORIES
  ${_JAVA_HOME}/jre/lib/{libarch}
  ${_JAVA_HOME}/jre/lib
  ${_JAVA_HOME}/lib
  ${_JAVA_HOME}
  /usr/lib
  /usr/local/lib
  /usr/lib/jvm/java/lib
  /usr/lib/java/jre/lib/{libarch}
  /usr/lib/jvm/jre/lib/{libarch}
  /usr/local/lib/java/jre/lib/{libarch}
  /usr/local/share/java/jre/lib/{libarch}
  /usr/lib/j2sdk1.4-sun/jre/lib/{libarch}
  /usr/lib/j2sdk1.5-sun/jre/lib/{libarch}
  /opt/sun-jdk-1.5.0.04/jre/lib/{libarch}
  /usr/lib/jvm/java-6-sun/jre/lib/{libarch}
  /usr/lib/jvm/java-1.5.0-sun/jre/lib/{libarch}
  /usr/lib/jvm/java-6-sun-1.6.0.00/jre/lib/{libarch}       # can this one be removed according to #8821 ? Alex
  #/usr/lib/jvm/java-6-openjdk/jre/lib/{libarch}        # Commented by Atul
  #/usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0/jre/lib/{libarch}        # fedora
  # Debian specific paths for default JVM
  #/usr/lib/jvm/default-java/jre/lib/{libarch}        # Commented by Atul
  #/usr/lib/jvm/default-java/jre/lib          # Commented by Atul
  #/usr/lib/jvm/default-java/lib              # Commented by Atul
  # OpenBSD specific paths for default JVM
  /usr/local/jdk-1.7.0/jre/lib/{libarch}
  /usr/local/jre-1.7.0/lib/{libarch}
  /usr/local/jdk-1.6.0/jre/lib/{libarch}
  /usr/local/jre-1.6.0/lib/{libarch}
  /usr/lib/jvm/java-7-oracle/jre/lib/{libarch} # This is added Atul
  )

在脚本查找包含库的部分...

set(JAVA_AWT_INCLUDE_DIRECTORIES
  "[HKEY_LOCAL_MACHINE\\SOFTWARE\\JavaSoft\\Java Development Kit\\1.4;JavaHome]/include"
  "[HKEY_LOCAL_MACHINE\\SOFTWARE\\JavaSoft\\Java Development Kit\\1.3;JavaHome]/include"
  "[HKEY_LOCAL_MACHINE\\SOFTWARE\\JavaSoft\\Java Development Kit\\${java_install_version};JavaHome]/include"
  ${_JAVA_HOME}/include
  /usr/include
  /usr/local/include
  /usr/lib/java/include
  /usr/local/lib/java/include
  /usr/lib/jvm/java/include
  /usr/lib/jvm/java-6-sun/include
  /usr/lib/jvm/java-1.5.0-sun/include
  /usr/lib/jvm/java-6-sun-1.6.0.00/include       # can this one be removed according to #8821 ? Alex
  #/usr/lib/jvm/java-6-openjdk/include
  /usr/local/share/java/include
  /usr/lib/j2sdk1.4-sun/include
  /usr/lib/j2sdk1.5-sun/include
  /opt/sun-jdk-1.5.0.04/include
  # Debian specific path for default JVM
  #/usr/lib/jvm/default-java/include
  # OpenBSD specific path for default JVM
  /usr/local/jdk-1.7.0/include
  /usr/local/jdk-1.6.0/include
  /usr/lib/jvm/java-7-oracle/include
  )

然后，我严格按照说明为安卓构建了openCV。

我不得不注释掉openjdk和default相关的行，因为它们与oracle安装冲突。