JavaPersistenceWithHibernate第二版笔记-第六章-Mapping inheritance-007Inheritance of embeddable classes(@MappedSuperclass、@Embeddable、@AttributeOverrides、、)

一、结构

二、代码

1.

 package org.jpwh.model.inheritance.embeddable;

 import javax.persistence.MappedSuperclass;
 import javax.validation.constraints.NotNull;

 @MappedSuperclass
 public abstract class Measurement {

     @NotNull
     protected String name;

     @NotNull
     protected String symbol;

     // ...
     protected Measurement() {
     }

     public Measurement(String name, String symbol) {
         this.name = name;
         this.symbol = symbol;
     }

     public String getName() {
         return name;
     }

     public String getSymbol() {
         return symbol;
     }

     public void setName(String name) {
         this.name = name;
     }

     public void setSymbol(String symbol) {
         this.symbol = symbol;
     }
 }

2.

 package org.jpwh.model.inheritance.embeddable;

 import javax.persistence.AttributeOverride;
 import javax.persistence.AttributeOverrides;
 import javax.persistence.Column;
 import javax.persistence.Embeddable;
 import javax.validation.constraints.NotNull;
 import java.math.BigDecimal;

 @Embeddable
 @AttributeOverrides({
         @AttributeOverride(name = "name",
                 column = @Column(name = "DIMENSIONS_NAME")),
         @AttributeOverride(name = "symbol",
                 column = @Column(name = "DIMENSIONS_SYMBOL"))
 })
 public class Dimensions extends Measurement {

     public static Dimensions centimeters(BigDecimal width, BigDecimal height, BigDecimal depth) {
         return new Dimensions("centimeters", "cm", width, height, depth);
     }

     public static Dimensions inches(BigDecimal width, BigDecimal height, BigDecimal depth) {
         return new Dimensions("inches", "\"", width, height, depth);
     }

     @NotNull
     protected BigDecimal depth;

     @NotNull
     protected BigDecimal height;

     @NotNull
     protected BigDecimal width;

     // ...
     public Dimensions() {
     }

     public Dimensions(String name, String symbol, BigDecimal width, BigDecimal height, BigDecimal depth) {
         super(name, symbol);
         this.height = height;
         this.width = width;
         this.depth = depth;
     }

     public BigDecimal getDepth() {
         return depth;
     }

     public BigDecimal getHeight() {
         return height;
     }

     public BigDecimal getWidth() {
         return width;
     }

     public void setDepth(BigDecimal depth) {
         this.depth = depth;
     }

     public void setHeight(BigDecimal height) {
         this.height = height;
     }

     public void setWidth(BigDecimal width) {
         this.width = width;
     }

     public String toString() {
         return String.format("W:%s%s x H:%s%s x D:%s%s", this.height, this.symbol, this.width, this.symbol, this.depth, this.symbol);
     }
 }

3.

 package org.jpwh.model.inheritance.embeddable;

 import javax.persistence.AttributeOverride;
 import javax.persistence.AttributeOverrides;
 import javax.persistence.Column;
 import javax.persistence.Embeddable;
 import javax.validation.constraints.NotNull;
 import java.math.BigDecimal;

 @Embeddable
 @AttributeOverrides({
         @AttributeOverride(name = "name",
                 column = @Column(name = "WEIGHT_NAME")),
         @AttributeOverride(name = "symbol",
                 column = @Column(name = "WEIGHT_SYMBOL"))
 })
 public class Weight extends Measurement {

     public static Weight kilograms(BigDecimal weight) {
         return new Weight("kilograms", "kg", weight);
     }

     public static Weight pounds(BigDecimal weight) {
         return new Weight("pounds", "lbs", weight);
     }

     @NotNull
     @Column(name = "WEIGHT")
     protected BigDecimal value;

     // ...
     public Weight() {
     }

     public Weight(String name, String symbol, BigDecimal weight) {
         super(name, symbol);
         this.value = weight;
     }

     public BigDecimal getValue() {
         return value;
     }

     public void setValue(BigDecimal value) {
         this.value = value;
     }

     public String toString() {
         return String.format("%s%s", this.value, this.symbol);
     }
 }

4.

 package org.jpwh.model.inheritance.embeddable;

 import org.jpwh.model.Constants;

 import javax.persistence.Entity;
 import javax.persistence.GeneratedValue;
 import javax.persistence.Id;
 import javax.validation.constraints.NotNull;
 import javax.validation.constraints.Size;

 @Entity
 public class Item {

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

     @NotNull
     @Size(
             min = 2,
             max = 255,
             message = "Name is required, maximum 255 characters."
     )

     protected String name;

     protected Dimensions dimensions;

     protected Weight weight;

     // ...

     public Item() {
     }

     public Item(String name, Dimensions dimensions, Weight weight) {
         this.name = name;
         this.dimensions = dimensions;
         this.weight = weight;
     }

     public Dimensions getDimensions() {
         return dimensions;
     }

     public Long getId() { // Optional but useful
         return id;
     }

     public String getName() {
         return name;
     }

     public Weight getWeight() {
         return weight;
     }

     public void setDimensions(Dimensions dimensions) {
         this.dimensions = dimensions;
     }

     public void setName(String name) {
         this.name = name;
     }

     public void setWeight(Weight weight) {
         this.weight = weight;
     }

 }

5.