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;
    }

    // ...
}