我有 Datastore 类，我使用这个类来尝试 GCM 。我不明白数据的保存位置（注册 ID），但我可以在重新启动我的 IDE（Eclipse）后检索它
谢谢朋友
private static final DatastoreService datastore =
DatastoreServiceFactory.getDatastoreService();
private Datastore() {
throw new UnsupportedOperationException();
}
/**
* Registers a device.
*
* @param regId device's registration id.
*/
public static void register(String regId) {
logger.info("Registering " + regId);
Transaction txn = datastore.beginTransaction();
try {
Entity entity = findDeviceByRegId(regId);
if (entity != null) {
logger.fine(regId + " is already registered; ignoring.");
return;
}
entity = new Entity(DEVICE_TYPE);
entity.setProperty(DEVICE_REG_ID_PROPERTY, regId);
datastore.put(entity);
txn.commit();
} finally {
if (txn.isActive()) {
txn.rollback();
}
}
}
/**
* Gets all registered devices.
*/
public static List<String> getDevices() {
List<String> devices;
Transaction txn = datastore.beginTransaction();
try {
Query query = new Query(DEVICE_TYPE);
Iterable<Entity> entities =
datastore.prepare(query).asIterable(DEFAULT_FETCH_OPTIONS);
devices = new ArrayList<String>();
for (Entity entity : entities) {
String device = (String) entity.getProperty(DEVICE_REG_ID_PROPERTY);
devices.add(device);
}
txn.commit();
} finally {
if (txn.isActive()) {
txn.rollback();
}
}
return devices;
}