Possible Duplicate:
what is wrong with this call to the java method?
只要按下转义键,以下 C 代码片段就会调用 java 函数。 C 代码片段的第一个 block 在不同的线程上执行,第二个 block 在不同的线程上执行。当我按转义键时,消息 escape key pressed
显示,然后jvm崩溃。为什么java函数没有被调用?
C 代码:
if(called) {// starts on a different thread
switch(param) {
case VK_CONTROL:
printf("Control pressed !\n");
//(*Env)->CallVoidMethodA(Env,Obj,mid,"11");
break;
case VK_SHIFT:
printf("Shift pressed !\n");
//(*Env)->CallVoidMethodA(Env,Obj,mid,"10");
break;
case VK_ESCAPE:
printf("Escape pressed !\n");
JavaVM *jvm;
JNIEnv *env;
jmethodID mid;
env = (*jvm)->AttachCurrentThread(jvm,&env,NULL);
jclass cls = (*env)->GetObjectClass(env,Obj);
mid = (*env)->GetMethodID(env,cls,"callBack","(Ljava/lang/String;)V");
(*env)->CallVoidMethodA(env,Obj,mid,(*env)->NewStringUTF(env,"1B")); // Calling the java function
break;
default:
printf("The default case\n");
break;
}}
void Java_keylogger_TestKeys_initializeJNIVars
(JNIEnv *env, jobject obj) { // starts on a different thread
Obj = (*env)->NewGlobalRef(env,obj);
if(Obj == NULL) {
printf("Obj is Null\n");
}
called = TRUE;
}
Java 代码片段:
public void callBack(String key) {
String x = KeyEvent.getKeyText(Integer.parseInt(key, 16));
System.out.println(x);
}
最佳答案
您需要初始化您的jvm
变量。您可以使用 JNI_CreateJavaVM() 方法来执行此操作。请参阅此处了解更多信息:http://docs.oracle.com/javase/1.4.2/docs/guide/jni/spec/invocation.html
关于java - 一旦我按下Escape键,jvm就会崩溃,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/10912878/