利用Java的String类来完成字符编码转换

/**
* 利用Java的String类来完成字符编码转换
*/
char* Jstring2CStr(JNIEnv* env, jstring jstr) {
char* rtn = NULL;
jclass clsstring = (*env)->FindClass(env,"java/lang/String");
jstring strencode = (*env)->NewStringUTF(env,"GB2312"); //转换成Cstring的GB2312，兼容ISO8859-1
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);
memcpy(rtn, ba, alen);
rtn[alen] = 0; //"\0"
}
(*env)->ReleaseByteArrayElements(env,barr, ba, 0);
return rtn;
}