我正在实现一个“反向”JNI，以便在本教程之后从C调用Java：How to Call Java Functions from C Using JNI。每当我编译我的文件“CTest.cpp”，并在Windows命令提示符或Visual Studio中运行“CTest.exe”时，我总是会收到以下错误：
VM初始化期间发生错误无法加载本机库：找不到依赖库
我知道有类似的问题：我已经看过它们并应用了建议（例如将我的jvm.dll和jvm.lib路径链接到PATH环境变量）。我还通过Visual Studio在我的文件属性中添加了jvm.dll位置。我真的需要帮助 - 现在已经坚持了几天。谢谢你的时间！
CTest.cpp如下：
#include "StdAfx.h"
#include <stdio.h>
#include <jni.h>
#include <string.h>
#define PATH_SEPARATOR ';' /* define it to be ':' on Solaris */
#define USER_CLASSPATH "." /* where Prog.class is */
struct ControlDetail
{
int ID;
char Name[100];
char IP[100];
int Port;
};
struct WorkOrder
{
char sumSerialId[20];
char accessNumber[18];
char actionType[4];
char effectiveDate[24];
char fetchFlag[2];
char reason[456];
char accessSource[100];
};
JNIEnv* create_vm(JavaVM ** jvm) {
JNIEnv *env;
JavaVMInitArgs vm_args;
JavaVMOption options;
options.optionString = "-Djava.class.path=C:\\Users\\My Name\\Downloads\\src_CJNIJava\\Java Src\\TestStruct"; //Path to the java source code
vm_args.version = JNI_VERSION_1_8; //JDK version. This indicates version 1.8
vm_args.nOptions = 1;
vm_args.options = &options;
vm_args.ignoreUnrecognized = 0;
int ret = JNI_CreateJavaVM(jvm, (void**)&env, &vm_args);
if (ret < 0)
printf("\nUnable to Launch JVM\n");
return env;
}
int main(int argc, char* argv[])
{
JNIEnv *env;
JavaVM * jvm;
env = create_vm(&jvm);
if (env == NULL)
return 1;
struct ControlDetail ctrlDetail;
ctrlDetail.ID = 11;
strcpy(ctrlDetail.Name, "HR-HW");
strcpy(ctrlDetail.IP, "10.32.164.133");
ctrlDetail.Port = 9099;
printf("Struct Created in C has values:\nID:%d\nName:%s\n IP:%s\nPort:%d\n", ctrlDetail.ID, ctrlDetail.Name, ctrlDetail.IP, ctrlDetail.Port);
/********************************************************/
struct WorkOrder WO[2];
strcpy(WO[0].sumSerialId, "2000");
strcpy(WO[0].accessNumber, "2878430");
strcpy(WO[0].actionType, "04");
strcpy(WO[0].effectiveDate, "25-12-2007 12:20:30 PM");
strcpy(WO[0].fetchFlag, "0");
strcpy(WO[0].reason, "Executed Successfully");
strcpy(WO[0].accessSource, "PMS");
strcpy(WO[1].sumSerialId, "1000");
strcpy(WO[1].accessNumber, "2878000");
strcpy(WO[1].actionType, "T4");
strcpy(WO[1].effectiveDate, "25-12-2007 11:20:30 PM");
strcpy(WO[1].fetchFlag, "0");
strcpy(WO[1].reason, "");
strcpy(WO[1].accessSource, "RMS");
jclass clsH = NULL;
jclass clsC = NULL;
jclass clsW = NULL;
jclass clsR = NULL;
jmethodID midMain = NULL;
jmethodID midCalling = NULL;
jmethodID midDispStruct = NULL;
jmethodID midDispStructArr = NULL;
jmethodID midRetObjFunc = NULL;
jmethodID midCtrlDetConst = NULL;
jmethodID midWoConst = NULL;
jobject jobjDet = NULL;
jobject jobjRetData = NULL;
jobjectArray jobjWOArr = NULL;
//Obtaining Classes
clsH = env->FindClass("HelloWorld");
clsC = env->FindClass("ControlDetail");
clsW = env->FindClass("WorkOrder");
//Obtaining Method IDs
if (clsH != NULL)
{
midMain = env->GetStaticMethodID(clsH, "main", "([Ljava/lang/String;)V");
midCalling = env->GetStaticMethodID(clsH, "TestCall", "(Ljava/lang/String;)V");
midDispStruct = env->GetStaticMethodID(clsH, "DisplayStruct", "(LControlDetail;)I");
midDispStructArr = env->GetStaticMethodID(clsH, "DisplayStructArray", "([LWorkOrder;)V");
midRetObjFunc = env->GetStaticMethodID(clsH, "ReturnObjFunc", "()Ljava/lang/Object;");
}
else
{
printf("\nUnable to find the requested class\n");
}
if (clsC != NULL)
{
//Get constructor ID for ControlDetail
midCtrlDetConst = env->GetMethodID(clsC, "<init>", "(ILjava/lang/String;Ljava/lang/String;I)V");
}
else
{
printf("\nUnable to find the requested class\n");
}
if (clsW != NULL)
{
//Get Constructor ID for WorkOrder
midWoConst = env->GetMethodID(clsW, "<init>", "(Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;Ljava/lang/String;)V");
}
else
{
printf("\nUnable to find the requested class\n");
}
/************************************************************************/
/* Now we will call the functions using the their method IDs */
/************************************************************************/
if (midMain != NULL)
env->CallStaticVoidMethod(clsH, midMain, NULL); //Calling the main method.
if (midCalling != NULL)
{
jstring StringArg = env->NewStringUTF("\nTestCall:Called from the C Program\n");
//Calling another static method and passing string type parameter
env->CallStaticVoidMethod(clsH, midCalling, StringArg);
}
printf("\nGoing to Call DisplayStruct\n");
if (midDispStruct != NULL)
{
if (clsC != NULL && midCtrlDetConst != NULL)
{
jstring StringArgName = env->NewStringUTF(ctrlDetail.Name);
jstring StringArgIP = env->NewStringUTF(ctrlDetail.IP);
//Creating the Object of ControlDetail.
jobjDet = env->NewObject(clsC, midCtrlDetConst, (jint)ctrlDetail.ID, StringArgName, StringArgIP, (jint)ctrlDetail.Port);
}
if (jobjDet != NULL && midDispStruct != NULL)
env->CallStaticIntMethod(clsH, midDispStruct, jobjDet); //Calling the method and passing ControlDetail Object as parameter
}
//Calling a function from java and passing Structure array to it.
printf("\n\nGoing to call DisplayStructArray From C\n\n");
if (midDispStructArr != NULL)
{
if (clsW != NULL && midWoConst != NULL)
{
//Creating the Object Array that will contain 2 structures.
jobjWOArr = (jobjectArray)env->NewObjectArray(2, clsW, env->NewObject(clsW, midWoConst, env->NewStringUTF(""), env->NewStringUTF(""), env->NewStringUTF(""),
env->NewStringUTF(""), env->NewStringUTF(""), env->NewStringUTF(""), env->NewStringUTF("")));
//Initializing the Array
for (int i = 0; i<2; i++)
{
env->SetObjectArrayElement(jobjWOArr, i, env->NewObject(clsW, midWoConst, env->NewStringUTF(WO[i].sumSerialId),
env->NewStringUTF(WO[i].accessNumber),
env->NewStringUTF(WO[i].actionType),
env->NewStringUTF(WO[i].effectiveDate),
env->NewStringUTF(WO[i].fetchFlag),
env->NewStringUTF(WO[i].reason),
env->NewStringUTF(WO[i].accessSource)));
}
}
//Calling the Static method and passing the Structure array to it.
if (jobjWOArr != NULL && midDispStructArr != NULL)
env->CallStaticVoidMethod(clsW, midDispStructArr, jobjWOArr);
}
//Calling a Static function that return an Object
if (midRetObjFunc != NULL)
{
//Calling the function and storing the return object into jobject type variable
//Returned object is basically a structure having two fields (string and integer)
jobjRetData = (jobject)env->CallStaticObjectMethod(clsH, midRetObjFunc, NULL);
//Get the class of object
clsR = env->GetObjectClass(jobjRetData);
//Obtaining the Fields data from the returned object
jint nRet = env->GetIntField(jobjRetData, env->GetFieldID(clsR, "returnValue", "I"));
jstring jstrLog = (jstring)env->GetObjectField(jobjRetData, env->GetFieldID(clsR, "Log", "Ljava/lang/String;"));
const char *pLog = env->GetStringUTFChars(jstrLog, 0);
printf("\n\nValues Returned from Object are:\nreturnValue=%d\nLog=%s", nRet, pLog);
//After using the String type data release it.
env->ReleaseStringUTFChars(jstrLog, pLog);
}
//Release resources.
int n = jvm->DestroyJavaVM();
return 0;
}