invokemethodlibrary.cpp

来自「< Professional Java,JDK 5 Edition>」· C++ 代码 · 共 50 行

// InvokeMethodLibrary.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"
#include "..\InvokeMethodExample.h"

JNIEXPORT void JNICALL Java_InvokeMethodExample_execMethods
  (JNIEnv *env, jobject obj)
{
    jclass childClass, parentClass;
    jmethodID parent_methodID, child_methodID;

    childClass = env->GetObjectClass(obj);
    parentClass = env->FindClass("InvokeMethodParentClass");

    if(childClass == NULL || parentClass == NULL) {
        printf("Couldn't obtain handle to parent or child class");
        return;
    }

    parent_methodID = env->GetMethodID(parentClass, "printMessage", "()V");
    child_methodID = env->GetMethodID(childClass, "printMessage", "()V");

    if(parent_methodID == NULL || child_methodID == NULL) {
        printf("Couldn't obtain handle to parent or child method");
        return;
    }

    // These two calls invoke the method on the child class
    env->CallVoidMethod(obj, parent_methodID);
    env->CallVoidMethod(obj, child_methodID);

    // These two calls invoke the method on the parent class
    env->CallNonvirtualVoidMethod(obj, childClass, parent_methodID);
    env->CallNonvirtualVoidMethod(obj, parentClass, parent_methodID);

    // These two calls invoke the method on the child class
    env->CallNonvirtualVoidMethod(obj, childClass, child_methodID);
    env->CallNonvirtualVoidMethod(obj, parentClass, child_methodID);
}

BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
    return TRUE;
}