对象未存储在Google App Engine数据存储区中

Question

I'm having a problem storing an object in the datastore. I have an object, MyObject, that I'm trying to store but when the code is executed nothing happens. I go to look at the datastore dashboard and MyObject isn't there. No exceptions are thrown and there are no errors.

Here's my object

@PersistenceCapable(identityType = IdentityType.APPLICATION)
public class MyObject{

@PrimaryKey
@Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
private Key key;

@Persistent
String name;

@Persistent
String beta;

@Persistent
double loc;


public MyObject(String name1){
    name = name1;
}

//getters and setters
}

and here's the code to store the object

public static void saveMyObject(MyObject a)throws Exception{
    PersistenceManager pm = PMF.get().getPersistenceManager();
    try{
        pm.makePersistent(a);
    }
    catch(Exception e){
        throw e;
    }
    finally{
        pm.close();
    }
}

Can anyone see what I'm missing?

Answer 1

It looks like you are using JDO, so you might want either to add a JDO tag or else mention that somewhere....

I would replace

try
{
  pm.makePersistent(a);
}

with

try
{
  MyObject myObj = new MyObject(a.getName());    // or whatever the getter is
  myObj.setField2(a.getField2());                // Copy 1 data member from a
  ...                                            // Make a MyObject.copy(...) method?
  pm.makePersistent(myObj);
}

The key thing is that JDO uses enhancement: magic bytecode that is inserted after main Java compilation. I manipulate my persistent entity objects within the lifecycle ("scope") of enhancement to get JDO to work.

I also use transactions for writing (I don't know your JDO auto-transaction setting(s)). I always use transactions when creating and persisting a new persistent entity. You might want to try that if the change above does not work.