java通过jni调用opencv处理图像

1. 建立java文件

public class getImageFeature {
static{
System.loadLibrary("getImageFeatureDll");
}
public native int getImageFeatureByName(String filename);
public native int getImageFeatureByMemory();

public static void main(String[] args) {
getImageFeature test=new getImageFeature();
String filename = "D:/testpic/6af1399a64d10a399ad3247c01656bb7.jpg";
System.out.println(test.getImageFeatureByName(filename));
}
}

2. 切换到工程src文件夹

javac getImageFeature.java

javah getImageFeature

生成 getImageFeature.h 文件

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class getImageFeature */

#ifndef _Included_getImageFeature
#define _Included_getImageFeature
#ifdef __cplusplus
extern "C" {
#endif
/*
* Class:     getImageFeature
* Method:    getImageFeatureByName
* Signature: (Ljava/lang/String;)I
*/
JNIEXPORT jint JNICALL Java_getImageFeature_getImageFeatureByName
(JNIEnv *, jobject, jstring);

/*
* Class:     getImageFeature
* Method:    getImageFeatureByMemory
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_getImageFeature_getImageFeatureByMemory
(JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

3. VS2013建立dll工程

添加getImageFeature.h 头文件，再添加getImageFeature.cpp文件，实现对应函数（工程属性中需包含jdk下的include目录）

C:\Program Files\Java\jdk1.8.0_20\include

C:\Program Files\Java\jdk1.8.0_20\include\win32

#include "getImageFeatureDll.h"
#include <opencv2/opencv.hpp>

/*
* Class:     getImageFeature
* Method:    getImageFeatureByName
* Signature: (Ljava/lang/String;)I
*/
JNIEXPORT jint JNICALL Java_getImageFeature_getImageFeatureByName
(JNIEnv *env, jobject obj, jstring filename)
{
const char *str_filename;
str_filename = env->GetStringUTFChars(filename, false);

cv::Mat image = cv::imread(str_filename);
cv::imshow("test", image);
cv::waitKey(20000);
return 0;

}

/*
* Class:     getImageFeature
* Method:    getImageFeatureByMemory
* Signature: ()I
*/
JNIEXPORT jint JNICALL Java_getImageFeature_getImageFeatureByMemory
(JNIEnv *, jobject)
{
return 0;
}

编译生成对应的dll

4. 执行java程序

将生成dll复制到java工程src文件夹下，java XX 运行程序