Java如何使用HashCodeBuilder类实现hashCode()方法？

package org.nhooo.example.commons.lang;

public class ObjectHashCodeDemo {

    public static void main(String[] args) {
        Book book1 = new Book(1L, "Spring Boot in Action", "Craig Walls");
        Book book2 = new Book(2L, "Docker in Action", "Jeff Nickoloff");
        Book book3 = book1;

        System.out.println("book1.hashCode() = " + book1.hashCode());
        System.out.println("book2.hashCode() = " + book2.hashCode());
        System.out.println("book3.hashCode() = " + book3.hashCode());
    }
}

package org.nhooo.example.commons.lang;

import org.apache.commons.lang3.builder.EqualsBuilder;
import org.apache.commons.lang3.builder.HashCodeBuilder;

import java.io.Serializable;

public class Book implements Serializable {
    private Long id;
    private String title;
    private String author;

    public Book(Long id, String title, String author) {
        this.id = id;
        this.title = title;
        this.author = author;
    }

    //〜在这里实现获取器和设置器。

    public boolean equals(Object o) {
        if (o == this) {
            return true;
        }

        if (!(o instanceof Book)) {
            return false;
        }

        Book that = (Book) o;
        return new EqualsBuilder()
            .append(this.id, that.id)
            .append(this.title, that.title)
            .append(this.author, that.author)
            .isEquals();

        // 您还可以使用EqualsBuilder类的反射。
        // 返回EqualsBuilder.reflectionEquals(this,that);
    }

    public int hashCode() {
        return new HashCodeBuilder()
            .append(id)
            .append(title)
            .append(author)
            .toHashCode();

        // 甚至使用最简单的反射方法
        // 下面。
        // 返回HashCodeBuilder.reflectionHashCode(this);
    }
}

Maven依赖

<!-- https://search.maven.org/remotecontent?filepath=org/apache/commons/commons-lang3/3.9/commons-lang3-3.9.jar -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.9</version>
</dependency>