这是在GAE中使用持久性设置和获取字符串值的正确方法吗？

Question

Is this the correct way to set and get a string value using persistance in GAE ?

I'm receiving error :

com.google.appengine.api.datastore.EntityNotFoundException: No entity was found matching the key: jsonString("jsonString")

Adding to store :

DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();

Key key = KeyFactory.createKey("jsonString", "jsonString");
Entity urlEntity = new Entity("jsonString" , key);
urlEntity.setProperty("urlVal", urlVal);

com.google.appengine.api.datastore.Key urlEntityKey = datastore.put(urlEntity);  

Returning from store :

    Key key = KeyFactory.createKey("jsonString", "jsonString");
    DatastoreService datastore = DatastoreServiceFactory.getDatastoreService();

    Entity entity = datastore.get(key);

Answer 1

Please review the below code, also you can find more details on how to use the app engine datastore API by reviewing the documentation here . Also review the notes in the Datastore Overview document.

DatastoreService ds = DatastoreServiceFactory.getDatastoreService();
Entity e = new Entity("data");
e.setProperty("jsonString", "myValue");
Key key = ds.put(e);
Entity entity = ds.get(key);
System .out.println(entity);