未解析的外部符号__imp__JNI_CreateJavaVM @ 12引用 [英] unresolved external symbol __imp__JNI_CreateJavaVM@12 referenced

问题描述

我想写一个调用Java方法的C ++程序。

我试图从C ++调用Java函数。如此处所述

http://docs.oracle.com/javase/6/docs/technotes/guides/jni/spec/invocation.html

但我得到这个错误，而调试和无法处理它。
我使用Visual studio 2012.
这里是我的代码C ++代码。

  #includestdafx.h
 #include< jni.h> / * where everything is defined * / 
 
使用namespace std; 
 
 int _tmain（int argc，_TCHAR * argv []）
 {
 JavaVM * jvm; / *表示Java VM * / 
 JNIEnv * env; / *指向本地方法接口的指针* / 
 JavaVMInitArgs vm_args; / * JDK / JRE 6 VM初始化参数* / 
 JavaVMOption * options = new JavaVMOption [1]; 
 options [0] .optionString =-Djava.class.path = C：\\Users\\yv\\workspace\\JNI\\bin; //我的类在这个目录下。 
 
 vm_args.version = 0x00010006; 
 vm_args.nOptions = 1; 
 vm_args.options = options; 
 vm_args.ignoreUnrecognized = false; 
 
 / *加载并初始化Java VM，在env * / 
中返回JNI接口
 *指针JNI_CreateJavaVM（& jvm，（void **）& env， & vm_args）; //我有错误msg无法将参数2从'JNIEnv **'转换为'void **'所以添加（void **）如一些其他来源中所述
 
删除选项; 
 jvm-> DestroyJavaVM（）; 
 
 
 return 0; 
} 
  

我的comp版本上安装的Java是
C：\Users \yv> JAVA -version
Java版本1.7.0_17
Java（TM）SE运行时环境（版本1.7.0_17-b02）
Java HotSpot VM（构建23.7-b01，混合模式）

和我的java代码。

  public class jniClass {
 / ** 
 * @param args 
 * / 
 public static void main（String [] args）{
 // TODO自动生成方法存根
 System.out.println（Hello，World！ 
 System.out.println（Arguments sent to this program：）; 
 if（args.length == 0）{
 System.out.println（（None））; 
} else {
 for（int i = 0; i  System.out.print（args [i] +）; 
} 
 System.out.println（）; 
} 
} 
} 
  

解决方案>

我解决了这个问题。
错误：

 未解析的外部符号_imp_JNI_CreateJavaVM @ 12引用
  

是因为jvm.lib没有链接。

方法。

使用LoadLibrary在运行时动态运行jvm.dll的第一个链接：

  HINSTANCE hinstLib = LoadLibrary（TEXT（D：\\desired_jvm\\jre6\\jvm.dll））; 
 typedef jint（JNICALL * PtrCreateJavaVM）（JavaVM **，void **，void *）; 
 PtrCreateJavaVM ptrCreateJavaVM =（PtrCreateJavaVM）GetProcAddress（hinstLib，JNI_CreateJavaVM）; 
 jint res = ptrCreateJavaVM（& jvm，（void **）& env，& vm_args）; 
  

第二个是将jvm.lib链接到您的项目。

右键单击项目 - >属性。

在属性对话框

在Linker-> Input-> AdditionalDependencies区域下添加jvm.lib。

在Linker-> General-> AdditionalLibraryDirectories下编写jvm.lib路径

I want to write a C++ program which calls Java method.

I am trying to invoke a Java function from C++. As described here

http://docs.oracle.com/javase/6/docs/technotes/guides/jni/spec/invocation.html

but I get this error while debugging and can not handle it. I m using Visual studio 2012. Here is my code C++ code.

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

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
JavaVM *jvm;       /* denotes a Java VM */
JNIEnv *env;       /* pointer to native method interface */
JavaVMInitArgs vm_args; /* JDK/JRE 6 VM initialization arguments */
JavaVMOption* options = new JavaVMOption[1];
options[0].optionString = "-Djava.class.path=C:\\Users\\yv\\workspace\\JNI\\bin";    // my class is under this directory. 

vm_args.version = 0x00010006; 
vm_args.nOptions = 1;
vm_args.options = options;
vm_args.ignoreUnrecognized = false;

/* load and initialize a Java VM, return a JNI interface
 * pointer in env */
JNI_CreateJavaVM(&jvm, (void **)&env, &vm_args);  // I got err msg "cannot convert parameter 2 from 'JNIEnv **' to 'void **' " so added (void **) as described in some other sources    

delete options;
jvm->DestroyJavaVM();


return 0;
}

Java installed on my comp version is C:\Users\yv>JAVA -version java version "1.7.0_17" Java(TM) SE Runtime Environment (build 1.7.0_17-b02) Java HotSpot(TM) 64-Bit Server VM (build 23.7-b01, mixed mode)

and my java code in case of need.

public class jniClass {
/**
 * @param args
 */
public static void main(String[] args) {
    // TODO Auto-generated method stub
    System.out.println("Hello, World!");
    System.out.println("Arguments sent to this program:");
    if (args.length == 0) {
        System.out.println("(None)");
    } else {
        for (int i=0; i<args.length; i++) {
            System.out.print(args[i] + " ");
        }
        System.out.println();
    }
}
}

解决方案

I solved the problem. The error:

unresolved external symbol _imp_JNI_CreateJavaVM@12 referenced

is because the jvm.lib is not being linked with.

It can be solved by two ways.

First link to jvm.dll dynamically at run time, by using LoadLibrary:

 HINSTANCE hinstLib = LoadLibrary(TEXT("D:\\desired_jvm\\jre6\\bin\\client\\jvm.dll"));
 typedef jint (JNICALL *PtrCreateJavaVM)(JavaVM **, void **, void *);
 PtrCreateJavaVM ptrCreateJavaVM = (PtrCreateJavaVM)GetProcAddress(hinstLib,"JNI_CreateJavaVM");
 jint res = ptrCreateJavaVM(&jvm, (void**)&env, &vm_args);

Second is link the jvm.lib to your project.

Right click on the project -> properties.

On the Properties dialog box

add jvm.lib under Linker->Input->AdditionalDependencies area.

And write jvm.lib path under Linker->General->AdditionalLibraryDirectories

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