MacOS简单的JNI使用过程(我的是个maven项目)

 private static final Logger log = LoggerFactory.getLogger(LinuxProcess.class);

   public MacOsXProcess() {
   }

   static {
       new FileUtils().loadLibrary("libmacjni.jnilib");
   }

   @Override
   public List getPids(int processId, String host) {
       List children = new ArrayList<>();
       Map parentPidMap = getParentPidMap(host);
       Map childrenParentPidMap = new HashMap<>();
       for (Map.Entry entry : parentPidMap.entrySet()) {
           childrenParentPidMap.put(entry.getValue(), entry.getKey());
       }

       Queue queue = new LinkedList<>();
       queue.add(processId);
       while (!queue.isEmpty()) {
           Integer currentPid = queue.poll();
           if (childrenParentPidMap.containsKey(currentPid)) {
               children.add(childrenParentPidMap.get(currentPid));
               queue.add(childrenParentPidMap.get(currentPid));
           }
       }
       log.info("Macos system ,get pids ={}", children);
       return children;
   }

   @Override
   public Map getParentPidMap(String host) {
       Map result = new HashMap<>();
       ProcessInfo[] processInfos = processTable();
       for (ProcessInfo processInfo : processInfos) {
           result.put(processInfo.getPid(), processInfo.getParentPid());
       }
       return result;
   }

   @Override
   public Integer getParentPid(int processId, String host) {
       return getParentPidMap(host).get(processId);
   }

   public native ProcessInfo[] processTable();

• 在项目的根目录下执行命令,产生的是MacOsXProcess.h文件

javah -classpath /Users/xxx/IdeaProjects/xxx/target/classes  org.apache.xxx.common.pid.process.MacOsXProcess

#include 


#ifndef _Included_org_apache_xxxx_common_pid_process_MacOsXProcess
#define _Included_org_apache_xxxx_common_pid_process_MacOsXProcess
#ifdef __cplusplus
extern "C" {
#endif

JNIEXPORT jobjectArray JNICALL Java_org_apache_xxxx_common_pid_process_MacOsXProcess_processTable
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

• 在MacOsXProcess.h中会有一句

#include 

jni.h是jdk中C语言库的头文件，在编译.c的时候需要指定jni.h的所在。在Mac OX中他所在的位置是：

${JAVA_HOME}/include

使用gcc编译

gcc -I/Library/Java/JavaVirtualMachines/jdk1.8.0_301.jdk/Contents/Home/include -c MacOsXProcess.c

就可以得到一个编译好的文件 MacOsXProcess.o,下面需要把.o文件打包成动态库。

gcc -dynamiclib -o libmacjni.jnilib MacOsXProcess.o

至此，java代码就可以调用c语言了。