使用JNI加载JAVA虚拟机

　在C中，直接使用JNI加载虚拟机，也是很有意思的想法。

　　这个工作不难，吾已经完成了。下面这个代码不是我的代码，没有真正测试过。以后有机会再测试。

#include <jni.h>
using namespace std;
 
int main(const int argc, const char** argv)
{
    JavaVMOption options[7];
    JNIEnv *env;
    JavaVM *jvm;
    JavaVMInitArgs vm_args;
 
    options[0].optionString = "-XX:+UseG1GC";
    options[1].optionString = "-XX:-UseAdaptiveSizePolicy";
    options[2].optionString = "-XX:-OmitStackTraceInFastThrow";
    options[3].optionString = "-Xmn512m";
    options[4].optionString = "-Xmx2048m";
    options[5].optionString = "-Djava.library.path=natives";
    options[6].optionString = "-Djava.class.path=.;libraries.zip;main.jar";
 
    std::memset(&vm_args, 0, sizeof(vm_args));
    vm_args.version = JNI_VERSION_1_8;
    vm_args.nOptions = 7;
    vm_args.options = options;
    cout << "start creat jvm!\n";
    long status = JNI_CreateJavaVM(&jvm, (void**)&env, &vm_args);
    if (status == JNI_ERR)
    {
        return 0;
    }
 
    cout << "jvm created success\n";
    jclass cls = env->FindClass("main/Main");
    if (cls != NULL)
    {
        jmethodID mid = env->GetStaticMethodID(cls, "main", "([Ljava/lang/String;)V");
        if (mid != NULL)
        {
            jclass clz_string = env->FindClass("java/lang/String");
            jobjectArray result = env->NewObjectArray(2, clz_string, NULL);
            jstring arg0 = env->NewStringUTF("first");
            env->SetObjectArrayElement(result, 0, arg0);
            jstring arg1 = env->NewStringUTF("second");
            env->SetObjectArrayElement(result, 1, arg1);
 
            env->CallStaticVoidMethod(cls, mid, result);
        }
        else
        {
            cout << "class not found\n";
        }
    jvm->DestroyJavaVM();
    return 0;
}