未定义引用`JNI_CreateJavaVM'linux

Question

我正在尝试熟悉JNI API,但无法获得要编译的示例c ++程序.

这是我用来编译的命令,下面是我正在尝试编译的程序.我得到的错误是:

/tmp/cczyqqyL.o: In function `main':
/home/nc/Desktop/jni/simple/ctojava/callJava.cpp:16: undefined reference to `JNI_CreateJavaVM'

编译:

g++ -g -I/usr/lib/jvm/java-7-oracle/include/ -I/usr/lib/jvm/java-7-oracle/include/linux/ -L/usr/bin/java -L/usr/lib/jvm/java-7-oracle/jre/lib/amd64/server/ -ljvm callJava.cpp

C++:

#include <jni.h> /* where everything is defined */

int main(){
    JavaVM *jvm; /* denotes a Java VM */
    JNIEnv *env; /* pointer to native method interface */

   JavaVMInitArgs vm_args;
   JavaVMOption options[1];
   options[0].optionString = "-Djava.class.path=/home/nc/Desktop/jni/simple/ctojava/";
   vm_args.version = JNI_VERSION_1_6;
   vm_args.options = options;
   vm_args.nOptions = 1;
   vm_args.ignoreUnrecognized = JNI_FALSE;

   /* Create the Java VM */
   int res = JNI_CreateJavaVM(&jvm, (void **)&env, &vm_args); // this is what it can't find

   /* invoke the Main.test method using the JNI */
   jclass cls = env->FindClass("Hello");
   jmethodID mid = env->GetStaticMethodID(cls, "staticInt", "(I)I");
   env->CallStaticVoidMethod(cls, mid,10);

   /* We are done. */
   jvm->DestroyJavaVM();
}

我已经搜索过这个问题并尝试了我找到的所有解决方案,但我仍然得到同样的错误......非常感谢任何帮助!

编辑:下面的Joni的答案有效(取决于您的编译器).如果别人发现这一点:运行编译后的输出时,不要忘记LD_LIBRARY_PATH = _path_to_your_libjvm.so_否则将无法找到LIB在运行时.

LD_LIBRARY_PATH=/usr/lib/jvm/java-7-oracle/jre/lib/amd64/server ./a.out

Answer 1

最近GCC找到符号的方式发生了变化:现在要链接的单元从左到右严格处理,-lYourLibrary如果命令行中没有任何东西需要它们,则会默默忽略对libraries()的引用.

要解决此问题,请-ljvm在使用它的编译单元之后移动,例如移到命令行的最后:

g++ -g -I/usr/lib/jvm/java-7-oracle/include/ -I/usr/lib/jvm/java-7-oracle/include/linux/ \
-L/usr/bin/java -L/usr/lib/jvm/java-7-oracle/jre/lib/amd64/server/ callJava.cpp -ljvm