用Java完成这些要求。定义Book类： （1）成员变量：书号、书名、作者、出版社、出版日期 （2）重写equals()、hashcode()、toString() （3）实现自然排序：按书名升序 （4）实现定制排序：按作者、出版日期、出版社

好的，这是一个关于Java编程的问题，我可以回答。下面是实现Book类的代码：

import java.util.Comparator;
import java.util.Date;
import java.util.Objects;

public class Book implements Comparable<Book> {
    private String bookNo;
    private String bookName;
    private String author;
    private String publisher;
    private Date publishDate;

    public Book(String bookNo, String bookName, String author, String publisher, Date publishDate) {
        this.bookNo = bookNo;
        this.bookName = bookName;
        this.author = author;
        this.publisher = publisher;
        this.publishDate = publishDate;
    }

    public String getBookNo() {
        return bookNo;
    }

    public void setBookNo(String bookNo) {
        this.bookNo = bookNo;
    }

    public String getBookName() {
        return bookName;
    }

    public void setBookName(String bookName) {
        this.bookName = bookName;
    }

    public String getAuthor() {
        return author;
    }

    public void setAuthor(String author) {
        this.author = author;
    }

    public String getPublisher() {
        return publisher;
    }

    public void setPublisher(String publisher) {
        this.publisher = publisher;
    }

    public Date getPublishDate() {
        return publishDate;
    }

    public void setPublishDate(Date publishDate) {
        this.publishDate = publishDate;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Book book = (Book) o;
        return Objects.equals(bookNo, book.bookNo);
    }

    @Override
    public int hashCode() {
        return Objects.hash(bookNo);
    }

    @Override
    public String toString() {
        return "Book{" +
                "bookNo='" + bookNo + '\'' +
                ", bookName='" + bookName + '\'' +
                ", author='" + author + '\'' +
                ", publisher='" + publisher + '\'' +
                ", publishDate=" + publishDate +
                '}';
    }

    @Override
    public int compareTo(Book o) {
        return this.bookName.compareTo(o.bookName);
    }

    public static Comparator<Book> authorComparator = new Comparator<Book>() {
        @Override
        public int compare(Book o1, Book o2) {
            int result = o1.author.compareTo(o2.author);
            if (result == 0) {
                result = o1.publishDate.compareTo(o2.publishDate);
                if (result == 0) {
                    result = o1.publisher.compareTo(o2.publisher);
                }
            }
            return result;
        }
    };
}

在这个代码中，我们定义了一个Book类，包含了书号、书名、作者、出版社、出版日期等成员变量。我们重写了equals()、hashCode()、toString()方法，实现了自然排序和定制排序。自然排序按照书名升序排序，定制排序按照作者、出版日期、出版社排序。

希望这个回答能够帮到你。