使用JNI时如何获取C ++中Java异常的描述？

ExceptionCheck()

首先，存储异常，然后获取获取有关的信息所必需的Java方法

Throwable

// Get the exception and clear as no// JNI calls can be made while an exception exists.jthrowable exception = pEnv->ExceptionOccurred();pEnv->ExceptionClear();jclass throwable_class = pEnv->FindClass("java/lang/Throwable");jmethodID mid_throwable_getCause =    pEnv->GetMethodID(throwable_class,"getCause","()Ljava/lang/Throwable;");jmethodID mid_throwable_getStackTrace =    pEnv->GetMethodID(throwable_class,"getStackTrace","()[Ljava/lang/StackTraceElement;");jmethodID mid_throwable_toString =    pEnv->GetMethodID(throwable_class,"toString","()Ljava/lang/String;");jclass frame_class = pEnv->FindClass("java/lang/StackTraceElement");jmethodID mid_frame_toString =    pEnv->GetMethodID(frame_class,"toString","()Ljava/lang/String;");

其次，递归构造错误消息（您可能需要修改此消息）：

std::string error_msg; // Could use ostringstream instead._append_exception_trace_messages(*pEnv,error_msg,exception,mid_throwable_getCause,mid_throwable_getStackTrace,mid_throwable_toString,mid_frame_toString);void _append_exception_trace_messages(  JNIEnv&      a_jni_env,  std::string& a_error_msg,  jthrowable   a_exception,  jmethodID    a_mid_throwable_getCause,  jmethodID    a_mid_throwable_getStackTrace,  jmethodID    a_mid_throwable_toString,  jmethodID    a_mid_frame_toString){    // Get the array of StackTraceElements.    jobjectArray frames =        (jobjectArray) a_jni_env.CallObjectMethod(       a_exception,       a_mid_throwable_getStackTrace);    jsize frames_length = a_jni_env.GetArrayLength(frames);    // Add Throwable.toString() before descending    // stack trace messages.    if (0 != frames)    {        jstring msg_obj = (jstring) a_jni_env.CallObjectMethod(a_exception,     a_mid_throwable_toString);        const char* msg_str = a_jni_env.GetStringUTFChars(msg_obj, 0);        // If this is not the top-of-the-trace then        // this is a cause.        if (!a_error_msg.empty())        { a_error_msg += "nCaused by: "; a_error_msg += msg_str;        }        else        { a_error_msg = msg_str;        }        a_jni_env.ReleaseStringUTFChars(msg_obj, msg_str);        a_jni_env.DeleteLocalRef(msg_obj);    }    // Append stack trace messages if there are any.    if (frames_length > 0)    {        jsize i = 0;        for (i = 0; i < frames_length; i++)        { // Get the string returned from the 'toString()' // method of the next frame and append it to // the error message. jobject frame = a_jni_env.GetObjectArrayElement(frames, i); jstring msg_obj =     (jstring) a_jni_env.CallObjectMethod(frame,         a_mid_frame_toString); const char* msg_str = a_jni_env.GetStringUTFChars(msg_obj, 0); a_error_msg += "n    "; a_error_msg += msg_str; a_jni_env.ReleaseStringUTFChars(msg_obj, msg_str); a_jni_env.DeleteLocalRef(msg_obj); a_jni_env.DeleteLocalRef(frame);        }    }    // If 'a_exception' has a cause then append the    // stack trace messages from the cause.    if (0 != frames)    {        jthrowable cause =  (jthrowable) a_jni_env.CallObjectMethod(      a_exception,      a_mid_throwable_getCause);        if (0 != cause)        { _append_exception_trace_messages(a_jni_env, a_error_msg,  cause, a_mid_throwable_getCause, a_mid_throwable_getStackTrace, a_mid_throwable_toString, a_mid_frame_toString);        }    }}

我从几年前编写的代码（修改为消除样板代码）中复制了此代码

ExceptionCheck()