JNI中文乱码转换

jclass Class_string;        jmethodID mid_String,mid_getBytes;        jbyteArray bytes;        jbyte* log_utf8;        jstring codetype,jstr;Class_string = (*env)->FindClass(env,"java/lang/String");//获取class        //先将gbk字符串转为java里的string格式        mid_String = (*env)->GetMethodID(env,Class_string, "<init>", "([BLjava/lang/String;)V");        bytes = (*env)->NewByteArray(env,strlen(buf));        (*env)->SetByteArrayRegion(env,bytes, 0, strlen(buf), (jbyte*)buf);        codetype = (*env)->NewStringUTF(env,"gbk");        jstr= (jstring)(*env)->NewObject(env,Class_string, mid_String, bytes, codetype);        (*env)->DeleteLocalRef(env,bytes);        //再将string变utf-8字符串。        mid_getBytes =  (* env)->GetMethodID(env,Class_string,   "getBytes",   "(Ljava/lang/String;)[B");        codetype = (*env)->NewStringUTF(env,"utf-8");        bytes=(jbyteArray)(*env)->CallObjectMethod(env,jstr,mid_getBytes,codetype);        log_utf8=(*env)->GetByteArrayElements(env,bytes,JNI_FALSE);        LOGI(log_utf8); return (*env)->NewStringUTF(env,log_utf8);