JNI类型转换-白红宇

JNI类型转换

阅读量：7086 次

发布时间：2019-06-28

本文共 5374 字，大约阅读时间需要 17 分钟。

1	//jbytearray转c++byte数组

2	jbyte * arrayBody = env->GetByteArrayElements(data,0);

3	jsize theArrayLengthJ = env->GetArrayLength(data);

4	BYTE* starter = (BYTE*)arrayBody;

1	//jbyteArray 转 c++中的BYTE[]

2	//jbytearray array

3	jbyte * olddata = (jbyte*)env->GetByteArrayElements(array, 0);

4	jsize oldsize = env->GetArrayLength(array);

5	BYTE* bytearr = (BYTE*)olddata;

6	intlen = (int)oldsize;

1	//C++中的BYTE[]转jbyteArray

2	//nOutSize是BYTE数组的长度 BYTE pData[]

3	jbyte by = (jbyte)pData;

4	jbyteArray jarray = env->NewByteArray(nOutSize);

5	env->SetByteArrayRegin(jarray, 0, nOutSize, by);

1	//jbyteArray 转 char *

2	char* data = (char*)env->GetByteArrayElements(strIn, 0);

1	//char* 转jstring

2	jstring WindowsTojstring(JNIEnv* env,char* str_tmp)

{

4	jstring rtn=0;

5	intslen = (int)strlen(str_tmp);

6	unsignedshort* buffer=0;

7	if(slen == 0)

{

9	rtn = env->NewStringUTF(str_tmp);

}

else

{

13	intlength = MultiByteToWideChar(CP_ACP, 0, (LPCSTR)str_tmp, slen, NULL, 0);

14	buffer = (unsignedshort)malloc(length2+1);

15	if(MultiByteToWideChar(CP_ACP, 0, (LPCSTR)str_tmp, slen, (LPWSTR)buffer, length) > 0)

{

17	rtn = env->NewString((jchar*)buffer, length);

}

20	if(buffer)

{

22	free(buffer);

}

24	returnrtn;

}

1	//jstring 转 char* 或者 const char*

2	// jstring str

3	constchar*key = env->GetStringUTFChars(str, 0);

4	//jboolean isOffer

5	jsClient->modify(key, isOffer);

6	//需要释放，否则容易内存泄露

7	env->ReleaseStringUTFChars(str, key);

1	//JNI 返回 jbyteArray

2	JNIEXPORT jbyteArray JNICALL Java_Test_getByteArray(JNIEnv *env, jobject obj)

{

4	jbyteArray firstMacArray = env->NewByteArray( 6 );

......

6	jbyte *bytes = env->GetByteArrayElements( firstMacArray, 0);

7	for(inti = 0; i <sizeof( pAdapterInfo->Address ); i++ )

{

9	bytes[ i ] = pAdapterInfo->Address[ i ];

}

12	env->SetByteArrayRegion(firstMacArray, 0, 6, bytes );

13	returnfirstMacArray;

}

1	//jstring to char*

2	char* jstringTostring(JNIEnv* env, jstring jstr)

{

4	char* rtn = NULL;

5	jclass clsstring = env->FindClass("java/lang/String");

6	jstring strencode = env->NewStringUTF("utf-8");

7	jmethodID mid = env->GetMethodID(clsstring,"getBytes","(Ljava/lang/String;)[B");

8	jbyteArray barr= (jbyteArray)env->CallObjectMethod(jstr, mid, strencode);

9	jsize alen = env->GetArrayLength(barr);

10	jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);

11	if(alen > 0)

{

13	rtn = (char*)malloc(alen + 1);

14	memcpy(rtn, ba, alen);

15	rtn[alen] = 0;

}

17	env->ReleaseByteArrayElements(barr, ba, 0);

18	returnrtn;

}

1	char* to jstring

2	jstring stoJstring(JNIEnv* env,constchar* pat)

{

4	jclass strClass = env->FindClass("Ljava/lang/String;");

5	jmethodID ctorID = env->GetMethodID(strClass,"<init>","([BLjava/lang/String;)V");

6	jbyteArray bytes = env->NewByteArray(strlen(pat));

7	env->SetByteArrayRegion(bytes, 0,strlen(pat), (jbyte*)pat);

8	jstring encoding = env->NewStringUTF("utf-8");

9	return(jstring)env->NewObject(strClass, ctorID, bytes, encoding);

}

1	//将jstring类型转换成windows类型

2	char* jstringToWindows( JNIEnv *env, jstring jstr )

{

4	intlength = (env)->GetStringLength(jstr );

5	constjchar* jcstr = (env)->GetStringChars(jstr, 0 );

6	char* rtn = (char)malloc( length2+1 );

7	intsize = 0;

8	size = WideCharToMultiByte( CP_ACP, 0, (LPCWSTR)jcstr, length, rtn,(length*2+1), NULL, NULL );

9	if( size <= 0 )

10	returnNULL;

11	(env)->ReleaseStringChars(jstr, jcstr );

12	rtn[size] = 0;

13	returnrtn;

}

1	//将windows类型转换成jstring类型

2	jstring WindowsTojstring( JNIEnv* env,char* str )

{

4	jstring rtn = 0;

5	intslen =strlen(str);

6	unsignedshort* buffer = 0;

7	if( slen == 0 )

8	rtn = (env)->NewStringUTF(str );

else

{

11	intlength = MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, NULL, 0 );

12	buffer = (unsignedshort)malloc( length2 + 1 );

13	if( MultiByteToWideChar( CP_ACP, 0, (LPCSTR)str, slen, (LPWSTR)buffer, length ) >0 )

14	rtn = (env)->NewString( (jchar*)buffer, length );

}

16	if( buffer )

17	free( buffer );

18	returnrtn;

}

20	/*JNIEXPORT jstring JNICALL Java_test_cs_web_SWIFTAlianceCASmfTest_strcal

21	(JNIEnv *env, jclass obj, jstring jstr1, jstring jstr2)

{

23	jbyteArray bytes = 0;

24	jthrowable exc;

25	char *pszResult = NULL;

26	char *pszSTR1 = NULL;

27	char *pszSTR2 = NULL;

29	pszSTR1 = jstringTostring(env, jstr1);

30	pszSTR2 = jstringTostring(env, jstr2);

33	int nlen = sizeof(char)*(strlen(pszSTR1)+strlen(pszSTR2));

34	pszResult = (char*)malloc(nlen);

35	strcpy(pszResult, pszSTR1);

36	strcat(pszResult, pszSTR2);

38	jstring jstrRe = stoJstring(env, pszResult);

39	free(pszSTR1);

40	free(pszSTR2);

41	free(pszResult);

42	return(jstrRe);

}

1	//从传进来的对象中取出byte[]

2	jfieldID byteData = (env)->GetFieldID(clazz,"bData","[B");

3	jbyteArray pDataIn = (jbyteArray) (env)->GetObjectField(objDataIn, byteData);

4	jsize theArrayLeng = env->GetArrayLength(pDataIn);

1	//byte[]转为BYTE[]

2	jbyte * arrayBody = env->GetByteArrayElements(pDataIn,0);

3	BYTE* jDataIn = (BYTE*)arrayBody;

1	//将BYTE数组转为jarray

2	jbyte* byte = (jbyte*)jDataOut;

3	jbyteArray jarray = env->NewByteArray(theArrayLeng);

4	env->SetByteArrayRegion(jarray, 0, theArrayLeng, byte);

1	//给每一个实例的变量付值

2	(env)->SetObjectField(objDataIn,byteData,jarray);

3	(env)->SetIntField(objDataIn,pDataInLen,jDataInLen);

4	(env)->ReleaseByteArrayElements(pDataIn, arrayBody, 0);

声明: 本文由()原创编译，转载请保留链接:

转载于:https://my.oschina.net/zhuzihasablog/blog/149481

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