c# – 访问冲突异常

我有一个调用C dll的c#程序,后者又调用 java dll(使用jet excelsior构建第三方程序).我将一个xml字符串从c#传递到java中,然后java将字符串返回到c#进行处理.

这适用于第一次迭代,但是在第二次迭代时我得到以下异常……

Attempted to read or write protected memory. This is often an
indication that other memory is corrupt.

以下是我将其列为相关代码,但如果您需要其他任何内容,请告诉我.

C#调用C dll

public static class DllCall
{
    [DllImport("Stubs",CallingConvention = CallingConvention.Cdecl)]
    public static extern int initDll([MarshalAs(UnmanagedType.LPStr)] string userDllName);

    [DllImport("Stubs",CallingConvention = CallingConvention.Cdecl)]
    public static extern void finalizeDll();

    [DllImport("Stubs",CallingConvention = CallingConvention.Cdecl)]
    public static extern UInt32 newClassInstance(String rootPath,String cfgPath,String logPath );

    [DllImport("Stubs",CallingConvention = CallingConvention.Cdecl)]
    public static extern String request(UInt32 hClassInst,[MarshalAs(UnmanagedType.LPStr)] String input);

    [DllImport("Stubs",CallingConvention = CallingConvention.Cdecl)]
    public static extern void close();


}

C dll中抛出错误的方法

const char* request(jobject obj,char* input )
{
    jstring inputString;
    jstring outputString;
    const char *nativeString;


    jmethodID mID = (*env)->getmethodID (env,jClass,"request","(Ljava/lang/String;)Ljava/lang/String;");
    if (!mID){
        printf("\nError: dllClass.request() not found\n");
        return 0;
    }

    inputString = (*env)->NewStringUTF(env,input);


    outputString = (*env)->CallObjectMethod(env,obj,mID,inputString);    

    nativeString = (*env)->GetStringUTFChars(env,outputString,0); 


    return nativeString;
}

这里要求的是实际导致异常的C#代码.

public string request(string xmlInput)
{
    LogManager.logMessage("Sending request to Java. Request is - " + xmlInput);
    string rs ="";
    Console.Write("Making request");
    //this works fine
    rs = DllCall.request(hClass,xmlInput); 
    Console.Write("---> request() rs = {0}\n",rs);
    // this throws the error
    rs = DllCall.request(hClass,"<?xml version='1.0' encoding='utf-8'?><moo><request name=\"Panel.Open.GetSelectionTemplate\"/></moo>"); 
    return rs;
}

在回应丹尼尔这里是宣告env的地方

#include <jni.h>
#include <windows.h>

jnienv  *env;
JavaVM  *jvm;
HANDLE  hUserDll;
jclass  jClass;
char*  dllname;

以下是它的初始化方式.

int initDll(char* userDllName) 
{
  jClass = NULL;
  hUserDll = loadDll(userDllName); 
  dllname = userDllName;
  initJavaRT(hUserDll,&jvm,&env); 
  jClass = lookForClass(env,"XActMain/XActgeminiX3/XActgeminiX3IFX");
  return jClass ? 1 : 0;
}

/*
 * Initialize JET run-time.
 */
void initJavaRT(HANDLE myDllHandle,JavaVM** pjvm,jnienv** penv)
{
    int            result;
    JavaVMInitArgs args;

    JNI_GetDefaultJavaVMInitArgs_func = 
             (jint (JNICALL *) (void *args))
             GetProcAddress (myDllHandle,"JNI_GetDefaultJavaVMInitArgs");

    JNI_CreateJavaVM_func =
             (jint (JNICALL *) (JavaVM **pvm,void **penv,void *args))
             GetProcAddress (myDllHandle,"JNI_CreateJavaVM");

    if(!JNI_GetDefaultJavaVMInitArgs_func) {
        printf ("%s doesn't contain public JNI_GetDefaultJavaVMInitArgs\n",dllname);
        exit (1);
    }

    if(!JNI_CreateJavaVM_func) {
        printf ("%s doesn't contain public JNI_CreateJavaVM\n",dllname);
        exit (1);
    }

    memset (&args,sizeof(args));
    args.version = JNI_VERSION_1_2;

    result = JNI_GetDefaultJavaVMInitArgs_func(&args);
    if (result != JNI_OK) {
        printf ("JNI_GetDefaultJavaVMInitArgs() Failed with result %d\n",result);
        exit(1);
    }

    /*
     * NOTE: no JVM is actually created
     * this call to JNI_CreateJavaVM is intended for JET RT initialization
     */
    result = JNI_CreateJavaVM_func (pjvm,(void **)penv,&args);
    if (result != JNI_OK) {
        printf ("JNI_CreateJavaVM() Failed with result %d\n",result);
        exit(1);
    }

    printf ("JET RT initialized\n");
    fflush (stdout);
}

这是对Joes关于初始化的评论的回应……

public class Test
 {
     public UInt32 hClass;

     public test()
     {
        initDll();
        newClassInstance(rootConfig,config,logFile);
     }

     ........

     public void newClassInstance(string rootPath,string cfgPath,string logPath)
     {
         hClass = DllCall.newClassInstance(rootPath,cfgPath,logPath);
         Console.Write("---> hClass = {0}\n",hClass);
     }
     public void initDll()
     {
             int rc = DllCall.initDll("dllClass.dll");
             Console.Write("---> initDll() rc = {0}\n",rc);
     }

汉斯指出了以下链接potential answer

但是我不知道如何修改我当前的代码以适应这个解决方案.

正如我所说,它工作一次然后在第二次迭代时崩溃.

解决方法

我不确定它为什么第一次工作,但是你将一个类对象(hClass)传递给请求而不是该类的实例.

rs = DllCall.request(hClass,xmlInput); //The error is thrown on this line

看看这是否解决了问题：

public string request(string xmlInput)
{
    LogManager.logMessage("Sending request to Java. Request is - " + xmlInput);
    string rs ="";
    Console.Write("Making request");

    UInt32 hClassInst = DllCall.newClassInstance(rootPath,logPath); // <-- New line,using your own rootPath,logPath variables
    rs = DllCall.request(hClassInst,xmlInput);                               // <-- Modified line,using hClassInst instead of hClass

    Console.Write("---> request() rs = {0}\n",rs);
    return rs;
}

如果这可以解决问题,那么您应该重构它并将newClassInstance调用拉出到先前的初始化方法.