从JNI调用main方法失败

Question

我创建了一个C++类,应该Main.main通过以下方式调用:http://docs.oracle.com/javase/7/docs/technotes/guides/jni/spec/invocation.html#wp9502.

我没有让它工作所以我遵循:http://www.coderanch.com/t/525082/CPP/create-JVM-native-code-call

并且:

imp_JNI_Crea"> http://www.codeproject.com/Questions/263687/Linker-error-undefined-reference-to- imp _JNI_Crea

这些都没有奏效.所以我把我的代码改回了oracle所说的Invocation API文章(第一个链接).

我的C++代码如下所示:

在JNI.hpp文件中:

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

class Jvm
{
private:
    JavaVM* jvm;
    JNIEnv* env;
    JavaVMInitArgs jvm_args;
    JavaVMOption* options;

public:
    Jvm();
};

在JNI.cpp文件中:

Jvm::Jvm()
{
    options = new JavaVMOption[3];

    options[0].optionString = "-Djava.compiler=NONE";
    options[1].optionString = "-Djava.class.path=C:/Users/Brandon/Documents/NetBeansProjects/Loader/build/classes";
    options[2].optionString = "-verbose:class";

    jvm_args.version = JNI_VERSION_1_6;
    jvm_args.nOptions = 3;
    jvm_args.options = options;
    jvm_args.ignoreUnrecognized = false;

    //JNI_GetDefaultJavaVMInitArgs(&jvm_args);
    JNI_CreateJavaVM(&jvm, reinterpret_cast<void**>(&env), &jvm_args);

    jclass MainClass = env->FindClass("loader.Main");


    //Crashes on the next line:
    jmethodID MainMethod = env->GetStaticMethodID(MainClass, "main", "([Ljava/lang/String;)V");

    MessageBox(NULL, "", "", 0);

    Sleep(1000);

    jvm->DestroyJavaVM();
    delete[] options;
}

我的java代码如下:

package loader;

public class Main {

    public static void main(String[] args) {
        //JavaProcess.exec(ClientApplet.class);
        System.out.println("Hello!");
    }
}

而且冗长的印刷品:

[Loaded loader.Main from file:/C:/Users/Brandon/Documents/NetBeansProjects/Loader/build/classes/]

Process returned -1073741571 (0xC00000FD)   execution time : 1.730 s
Press any key to continue.

我究竟做错了什么？为什么调用方法失败？该JNI.dll说我装是:C:\Program Files\Java\jdk1.7.0_21\jre\bin\server\jvm.dll因为最近Java 7u25没有bin\client\jvm.dll.

我甚至静态链接到jvm.lib : C:\Program Files\Java\jdk1.7.0_21\lib\jvm.lib.

Answer 1

jclass MainClass = env->FindClass("loader.Main");

这是错的.使用JNI函数时,必须使用斜杠而不是点,就像在方法签名中一样.

正确的代码是:

jclass MainClass = env->FindClass("loader/Main");