JavaPersistenceWithHibernate第二版笔记-第五章-Mapping value types-003使用@AttributeOverrides

Each @AttributeOverride for a component property is “complete”: any JPA or Hibernate annotation on the overridden property is ignored. This means the @Column annotations on the Address class are ignored—all BILLING_* columns are NULL able!(Bean Validation still recognizes the @NotNull annotation on the component property, though; Hibernate only overrides persistence annotations.)

1.

 package org.jpwh.model.simple;

 import org.jpwh.model.Constants;

 import javax.persistence.AttributeOverride;
 import javax.persistence.AttributeOverrides;
 import javax.persistence.Column;
 import javax.persistence.Embedded;
 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.persistence.Table;
 import java.io.Serializable;
 import java.math.BigDecimal;

 @Entity
 @Table(name = "USERS")
 public class User implements Serializable {

     @Id
     @GeneratedValue(generator = Constants.ID_GENERATOR)
     protected Long id;

     public Long getId() {
         return id;
     }

     protected String username;

     public User() {
     }

     public String getUsername() {
         return username;
     }

     public void setUsername(String username) {
         this.username = username;
     }

     // The Address is @Embeddable, no annotation needed here...
     protected Address homeAddress;

     public Address getHomeAddress() {
         return homeAddress;
     }

     public void setHomeAddress(Address homeAddress) {
         this.homeAddress = homeAddress;
     }

     @Embedded // Not necessary...
     @AttributeOverrides({
             @AttributeOverride(name = "street",
                     column = @Column(name = "BILLING_STREET")), // NULLable!
             @AttributeOverride(name = "zipcode",
                     column = @Column(name = "BILLING_ZIPCODE", length = 5)),
             @AttributeOverride(name = "city",
                     column = @Column(name = "BILLING_CITY"))
     })
     protected Address billingAddress;

     public Address getBillingAddress() {
         return billingAddress;
     }

     public void setBillingAddress(Address billingAddress) {
         this.billingAddress = billingAddress;
     }

     public BigDecimal calcShippingCosts(Address fromLocation) {
         // Empty implementation of business method
         return null;
     }

     // ...
 }