JavaPersistenceWithHibernate第二版笔记-第五章-Mapping value types-002使用@Embeddable

一、数据库

二、代码

1.

 package org.jpwh.model.simple;

 import javax.persistence.Column;
 import javax.persistence.Embeddable;
 import javax.validation.constraints.NotNull;

 /**
  *
  * Instead of <code>@Entity</code>, this component POJO is marked with <code>@Embeddable</code>. It
  * has no identifier property.
  */
 @Embeddable
 public class Address {

     @NotNull // Ignored for DDL generation!
     @Column(nullable = false) // Used for DDL generation!
     protected String street;

     @NotNull
     @Column(nullable = false, length = 5) // Override VARCHAR(255)
     protected String zipcode;

     @NotNull
     @Column(nullable = false)
     protected String city;

     /**
      * Hibernate will call this no-argument constructor to create an instance, and then
      * populate the fields directly.
      */
     protected Address() {
     }

     /**
      * You can have additional (public) constructors for convenience.
      */
     public Address(String street, String zipcode, String city) {
         this.street = street;
         this.zipcode = zipcode;
         this.city = city;
     }

     public String getStreet() {
         return street;
     }

     public void setStreet(String street) {
         this.street = street;
     }

     public String getZipcode() {
         return zipcode;
     }

     public void setZipcode(String zipcode) {
         this.zipcode = zipcode;
     }

     public String getCity() {
         return city;
     }

     public void setCity(String city) {
         this.city = city;
     }
 }

You should override the equals() and hashCode() methods of Address and compare instances by value.

2.

 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;
     }

     // ...
 }

3.

三、