将原始数组从java传递给c [英] passing array of primitives from java to c

问题描述

我有一个int数组，比如

I have a int array like

int[][] coordinates = {{346, 640, 499, 666},{555, 640, 675, 666}};

我试图使用JNI将此数组发送到C.我可以找到一维数组的明确解决方案，但不能找到多维数组。

and I am trying to send this array to C with using JNI. I could find clear solution for one dimensional array but not for multidimensional array.

<br />
public class PopulateCoordinates{<br />
public native void Coordinates(int[][] coordinates);<br />
<br />
 static {<br />
  System.loadLibrary("libPopulateCoordinates");<br />
 }<br />
 public static void main(String[] args) {<br />
<br />
  PopulateCoordinates h = new PopulateCoordinates();<br />
  int[][] coordinates = {{346, 640, 499, 666},{555, 640, 675, 666}};<br />
  h.Coordinates(coordinates);<br />
 }<br />
 }<br />

我的C代码有一个方法，它将填充从java传递的数组，如下所示

My C code has method which will populate its array that is passed from java like this

rect skip_rectarr[2] = { {346, 640, 499, 666}, { 555, 640, 675, 666 }};

<br />
typedef struct {<br />
int left;<br />
int top;<br />
int right;<br />
int bot;<br />
} rect;<br />
JNIEXPORT void JNICALL PopulateCoordinates_Coordinates(JNIEnv *env, jobject obj,jobjectArray inJNIArray)<br />
{<br />
//rect skip_rectarr[2] = { {346, 640, 499, 666}, { 555, 640, 675, 666 }};<br />
}<br />

我很难将jobject正确转换为int [] []到期缺乏本土发展知识。有人能告诉我最简单，最安全的方法吗？谢谢

I am having a hard time in properly converting jobject to int[][] due to lack of native development knowledge. Can anyone tell me the simplest and safest possible way? Thanks

推荐答案

说实话：最简单和最简单的方法是使用具有本机数据类型和AVOID结构的一维数组。 Java和C具有不同的内存布局。微软用.net语言解决了这个问题。



我会扩展rhe func的接口和大小信息：

To be honest: The simplest and savest way is to use one dimension arrays with native data types and AVOID structs. Java and C have different memory layouts. Microsoft has solved this mess on its .net-languages.

I would extend the interfaces of rhe func with size information:

JNIEXPORT void JNICALL PopulateCoordinates_CoordinatesRect(JNIEnv *env, jobject obj,jobjectArray inJNIArray, int countObjectes)

你不应该在接口上做很多事情，但更好地传输简单和原生数据。或者你可能会浪费很多时间。

You shouldnt fizzle to much on the interfaces, but better transfer simple and native data. Or you may waiste a lot of time.

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