C++可以调用Java代码吗？

Question

我知道Java代码可以通过JNI调用C++代码.但是,是否可以通过JNI或任何其他方法再次从C++调用Java代码？

Answer 1

是的,你当然可以.这是一个例子:

这是java文件:

public class InvocationHelloWorld {
    public static void main(String[] args) {
        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();
        }
    }
}

还有一些使用它的C++:

void invoke_class(JNIEnv* env) {
  jclass helloWorldClass;
  jmethodID mainMethod;
  jobjectArray applicationArgs;
  jstring applicationArg0;

  helloWorldClass = (env)->FindClass("InvocationHelloWorld");
  if(! helloWorldClass )
  {
    std::cerr<<"Couldn't get \"InvocationHelloWorld\""<<std::endl;
    return;
  }

  mainMethod = (env)->GetStaticMethodID(helloWorldClass, "main", "([Ljava/lang/String;)V");
  if(! mainMethod )
  {
    std::cerr<<"Coulnd't get \"InvocationHelloWorld::main\""<<std::endl;
    return;
  }

  applicationArgs = (env)->NewObjectArray(1, (env)->FindClass("java/lang/String"), NULL);
  applicationArg0 = (env)->NewStringUTF("From-C-program");
  (env)->SetObjectArrayElement(applicationArgs, 0, applicationArg0);

  (env)->CallStaticVoidMethod(helloWorldClass, mainMethod, applicationArgs);
}