java jni c++ 例子
1. java程序
public class TestHello { static { System.loadLibrary("TestHello"); } public static native int add(int a, int b); public static void main(String[] args) { int c = add(2, 5); System.out.print("result:::::"+c); } }
2 编译
javac TestHello.java
3. 生成c++头文件
javah TestHello
4. 创建 DLL动态链接库工程 TestHello
visual studio 2010: File->new->project->win32 project-> dll->TestHello
5. 引入 jni.h, jni_md.h TestHello.h
TestHello工程右键-> Properties->Configuration Properties->C/C++ ->General -> Additional Include Directories
6. 在TestHello.cpp中 实现TestHello.h中的函数
// TestHello.cpp : Defines the exported functions for the DLL application. // #include "stdafx.h" #include "dllApi.h" JNIEXPORT jint JNICALL Java_TestHello_add (JNIEnv * env, jclass obj, jint a, jint b){ int var =0; dllApi* test = new dllApi(); var = test->DLL_API_ADD(a, b); delete test; return var; };
dllApi.h
#pragma once class dllApi { public: dllApi(void); ~dllApi(void); int DLL_API_ADD(int , int ); int DLL_API_SUB(int , int ); int DLL_API_MUL(int , int ); int DLL_API_DIV(int , int ); };
dllApi.cpp
#include "StdAfx.h" #include "dllApi.h" dllApi::dllApi(void) { } dllApi::~dllApi(void) { } int dllApi :: DLL_API_ADD(int a, int b){ return (a + b); }; int dllApi :: DLL_API_SUB(int a, int b){ return (a-b); }; int dllApi :: DLL_API_MUL(int a, int b){ return (a*b); }; int dllApi :: DLL_API_DIV(int a, int b){ return (a/b); };
7. 编译生成TestHello.dll
8. 将dll文件拷贝到class目录下, 执行class文件,OK。