JNI操作二维数组

之前的文章讲解了有关JNI使用方法，这篇文章进阶一点，介绍下JNI操作二维数组的方法。有了之前文章的操作JNI的方法，这里直接上代码了。

Java代码部分

 package com.testjni;

 public class TestJNI

 {

     private static final int ONE_DIMENSION = 3;

     private static final int TWO_DIMENSION = 2;

     public native int test2DimensionArray(int[][] aHoleList);

     static

     {

         System.load("D:\\eclipseWebWorkSpace\\testest\\src\\com\\testjni\\libTestJNI_amd64.dll");

     }

     public static void main(String[] args)

     {

         TestJNI testJNI = new TestJNI();

         //测试二维数组

         int[][] test = new int[ONE_DIMENSION][TWO_DIMENSION];

         System.out.println("\njava before--->");

         for (int i = 0; i < ONE_DIMENSION; i++)

         {

             StringBuilder sb = new StringBuilder("test[");

             for (int j = 0; j < TWO_DIMENSION; j++)

             {

                 if (j == 0)

                 {

                     sb.append(i).append("] = ").append(test[i][j]).append(" ");

                 }

                 else

                 {

                     sb.append(test[i][j]).append(" ");

                 }

             }

             System.out.println(sb.toString());

         }

         int res = testJNI.test2DimensionArray(test);

         System.out.println("\njava after--->res=" + res);

         for (int i = 0; i < ONE_DIMENSION; i++)

         {

             StringBuilder sb = new StringBuilder("test[");

             for (int j = 0; j < TWO_DIMENSION; j++)

             {

                 if (j == 0)

                 {

                     sb.append(i).append("] = ").append(test[i][j]).append(" ");

                 }

                 else

                 {

                     sb.append(test[i][j]).append(" ");

                 }

             }

             System.out.println(sb.toString());

         }

     }

 }

C头文件

 /* DO NOT EDIT THIS FILE - it is machine generated */

 #include "jni.h"

 /* Header for class com_testjni_TestJNI */

 #ifndef _Included_com_testjni_TestJNI

 #define _Included_com_testjni_TestJNI

 #ifdef __cplusplus

 extern "C" {

 #endif

 /*

  * Class:     com_testjni_TestJNI

  * Method:    nativeBsmGetHoleList

  * Signature: ([[I)I

  */

 JNIEXPORT jint JNICALL Java_com_testjni_TestJNI_test2DimensionArray

   (JNIEnv *, jobject, jobjectArray);

 #ifdef __cplusplus

 }

 #endif

 #endif

C源码文件

 #include <stdio.h>

 #include "com_testjni_TestJNI.h"

 #define ONE_DIMENSION 3

 #define TWO_DIMENSION 2

 JNIEXPORT jint JNICALL Java_com_testjni_TestJNI_test2DimensionArray(JNIEnv *env, jobject obj, jobjectArray test)

 {

     int jniTest[ONE_DIMENSION][TWO_DIMENSION];

     for (int i = ; i < ONE_DIMENSION; i++)

     {

         for (int j = ; j < TWO_DIMENSION; j++)

         {

             jniTest[i][j] =  * (i + )+ j;

         }

     }

     printf("\njni:\n");

     jintArray testArray;

     for (int i = ; i < ONE_DIMENSION; i ++)

     {

         //从输入参数二维数组aHoleList中取出某个一维数组

         testArray = (jintArray)env->GetObjectArrayElement(test, i);

         printf("testArray[%d]=%d, %d, %d, testArray[0] addr = %d; testArray[1] addr = %d, testArray[2] addr = %d; testArray addr=%d; sizeof(jintArray)=%d\n",

             i, testArray[], testArray[], testArray[], &testArray[], &testArray[], &testArray[], testArray, sizeof(jintArray));

         //获取一维数组的指针

         jint *testP = env->GetIntArrayElements(testArray, NULL);

         printf("C before, testP[%d]=%d, %d, testP addr=%d\n", i, testP[], testP[], testP);

         //改变数组的值

         for (int j = ; j < TWO_DIMENSION; j++)

         {

              *(testP + j) = jniTest[i][j];

         }

         printf("C after, testP[%d]=%d, %d, testP addr=%d\n", i, testP[], testP[], testP);

         env->ReleaseIntArrayElements(testArray, testP, );

         printf("\n");

     }

     return ;

 }

运行结果

java before--->

test[] =

test[] =

test[] =   

java after--->res=

test[] =

test[] =

test[] =   

jni:

testArray[]=, , , testArray[] addr = ; testArray[] addr = , testArray[] addr = ; testArray addr=; sizeof(jintArray)=

C before, testP[]=, , testP addr=

C after, testP[]=, , testP addr=

testArray[]=, , , testArray[] addr = ; testArray[] addr = , testArray[] addr = ; testArray addr=; sizeof(jintArray)=

C before, testP[]=, , testP addr=

C after, testP[]=, , testP addr=

testArray[]=, , , testArray[] addr = ; testArray[] addr = , testArray[] addr = ; testArray addr=; sizeof(jintArray)=

C before, testP[]=, , testP addr=

C after, testP[]=, , testP addr=

总结：掌握C语言的核心知识点指针，各种操作水到渠成。

巴特西

JNI操作二维数组

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