Sriram Narayan说要对密钥进行字符串编码，以使其通过GWT的RPC机制传递：
@PersistenceCapable(identityType = IdentityType.APPLICATION) public class SomeDomainClass implements Serializable { @PrimaryKey @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY) @Extension(vendorName = "datanucleus", key = "gae.enpred-pk", value = "true") String id;
