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.