Android之——jni通用工具步骤

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1、将java字符串转化为c++字符串

/** *工具方法 *将java字符串转化为c++字符串 *返回字符串数组的首地址 */char* Jstring2CPPStr(JNIEnv* env, jstring jstr, jstring encode) {	char* rtn = NULL;	jclass clsstring = env->FindClass("java/lang/String");	jstring strencode = env->NewStringUTF(encode);	jmethodID mid = env->GetMethodID(clsstring, "getBytes","(Ljava/lang/String;)[B");	jbyteArray barr = (jbyteArray)env->CallObjectMethod(jstr, mid,strencode); // String .getByte("GB2312");	jsize alen = env->GetArrayLength(barr);	jbyte* ba = env->GetByteArrayElements(barr, JNI_FALSE);	if (alen > 0) {		rtn = (char*) malloc(alen + 1); //"\0"		memcpy(rtn, ba, alen);		rtn[alen] = 0;	}	env->ReleaseByteArrayElements(barr, ba, 0); //	return rtn;}

2、将java字符串转化为c字符串

/** *工具方法 *将java字符串转化为c字符串 *返回字符串数组的首地址 */char* Jstring2CStr(JNIEnv* env, jstring jstr, jstring encode) {	char* rtn = NULL;	jclass clsstring = (*env)->FindClass(env, "java/lang/String");	jstring strencode = (*env)->NewStringUTF(env, encode);	jmethodID mid = (*env)->GetMethodID(env, clsstring, "getBytes","(Ljava/lang/String;)[B");	jbyteArray barr = (jbyteArray)(*env)->CallObjectMethod(env, jstr, mid,strencode); // String .getByte("GB2312");	jsize alen = (*env)->GetArrayLength(env, barr);	jbyte* ba = (*env)->GetByteArrayElements(env, barr, JNI_FALSE);	if (alen > 0) {		rtn = (char*) malloc(alen + 1); //"\0"		memcpy(rtn, ba, alen);		rtn[alen] = 0;	}	(*env)->ReleaseByteArrayElements(env, barr, ba, 0); //	return rtn;}