通过JNI 实现 java与C++之间的信息传递

定义一个native 方法：
package ext;
import java.util.Hashtable;
public class TestJNI
{
   static
   {
       System.loadLibrary("dllfile");
   }
    public TestJNI()
    {
        Hashtable htable = new Hashtable();
        htable.put(1,2);
    }
    public native Hashtable getNameList();
    public static void main(String[] arg)
    {
        TestJNI tstJNI= new TestJNI();
        Hashtable htable= tstJNI.getNameList();
        System.out.println(htable.size());
    }
}
通过 javah 生成 头文件 ext_TestJNI.h
/* DO NOT EDIT THIS FILE - it is machine generated */
#include "jni.h"
/* Header for class ext_TestJNI */
#ifndef _Included_ext_TestJNI
#define _Included_ext_TestJNI
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     ext_TestJNI
 * Method:    getNameList
 * Signature: ()Ljava/util/Hashtable;
 */
JNIEXPORT jobject JNICALL Java_ext_TestJNI_getNameList
  (JNIEnv *, jobject);
#ifdef __cplusplus
}
#endif
#endif
在c++创建一个dynamic dll项目，并在 StdAfx.h 中 include 头文件 ext_TestJNI.h
StdAfx.h 代码：
 #if !defined(AFX_STDAFX_H__FAD3F2E4_D6E1_4011_9791_2256C4B0BDE6__INCLUDED_)
#define AFX_STDAFX_H__FAD3F2E4_D6E1_4011_9791_2256C4B0BDE6__INCLUDED_
#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
// Insert your headers here
#define WIN32_LEAN_AND_MEAN        // Exclude rarely-used stuff from Windows headers
#include <windows.h>
#include "ext_TestJNI.h"
在 CPP文件中定义  方法实现：
 CPP代码：
#include "stdAfx.h&