MONGODB's ORM Framework Morphia annotation two —————— @Id

Classes that are @entity annotations must have a unique @Id value, which is stored in the id attribute of the MongoDB database, which is a required index. Like in the Hotel class:

@Entity

public class hotel{

@Id

Private ObjectId ID;

.....

}

As shown above: The ID of the @id annotation is objectid type, so that you don't have to worry about the ID generation problem, MONGO will automatically generate a

  A unique new Objectid object (for the ID of the auto_increment type in MySQL). If you want to use a different type as the ID, then you have to save the data

  Assign a value manually to the ID.

English proficiency is limited, please master treatise

Original: Http://code.google.com/p/morphia/wiki/EntityAnnotation