jstring, which requires a subroutine call to in order to convert a Java Unicode string (2 bytes) to a C-style char* string (1 byte UTF-8 format).

To convert a jstring to a C-style string, you might write code like the following:

JNIEXPORT void JNICALLJava_MyJavaClass_printName(JNIEnv *env, jobject obj,
	jstring name)
{
	const char *str= (*env)->GetStringUTFChars(env,name,0);
	printf(“%s”, str);
	//need to release this string when done with it in order to
	//avoid memory leak
	(*env)->ReleaseStringUTFChars(env, name, str);
}

To convert a C-style string to jstring , you can use the (*env)->NewStringUTF() function to create a new jstring from a C-style string. For example, a C function that needs to return a Java string could contain the following code:

JNIEXPORT jstring JNICALLJava_MyJavaClass_getName(JNIEnv *env, jobject obj)
{
	return (*env)->NewStringUTF(env, “Electrofriends.com”);
}

The post How to convert a jstring to a C-style string or vice versa? first appeared on Student Projects.