Java JPA更新记录的一部分，不返回任何错误

我有一个使用JPA的java web应用程序。我的问题看起来很简单，但现在已经困扰了我一天了。 我的数据库中有两个表，Book和Author。 这些表的视图中的两个输入字段的格式相同

奇怪的是，当我更新（mrege（））这本书的编辑记录时，作者却没有更新。我已经调试并遵循了netbeans允许的author对象，当我合并（）我的新书记录时，只影响book表/对象

这本书是多对一的

作者是一对多的人

控制器

protected void processRequest(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setContentType("text/html;charset=UTF-8");

    try {

        String action = request.getParameter("action");

        if (action != null) {
            List<String> values;
            try {
                values = new ArrayList<>();

                switch (action) {

                    case "save": //                                 Ecompasses Save and Update
                        Book book = null;
                        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
                        Date date;

                        String bookAuthorID = request.getParameter("authorID");
                        String bookID = request.getParameter("bookID");
                        String title = request.getParameter("title");
                        String userEnteredDate = request.getParameter("datePublished");
                        Author author = null;

                        if (bookID.matches("\\d+")) {            // Update

                            book = bookService.find(new Integer(bookID));
                            book.setTitle(title);
                            book.setDatePublished(sdf.parse(userEnteredDate));

                            author = authorService.find(new Integer(bookAuthorID));
                            author.setAuthorFirstName(request.getParameter("authorFirstName"));
                            author.setAuthorLastName(request.getParameter("authorLastName"));
                            book.setAuthorID(author);

                            bookService.edit(book);


                        }
  }

---

应用级联类型。合并

@JoinColumn(name = "AuthorID", referencedColumnName = "AuthorID")
@ManyToOne(optional = false, cascade=CascadeType.MERGE)
private Author authorID;

---

应用级联类型。合并

@JoinColumn(name = "AuthorID", referencedColumnName = "AuthorID")
@ManyToOne(optional = false, cascade=CascadeType.MERGE)
private Author authorID;

---

你应用了级联操作吗？@Ish，这实际上破坏了程序。你说什么破坏了程序？您是否观察到任何错误或特定行为？是否应用了级联操作？@Ish，这实际上破坏了程序。什么意思破坏了程序？您是否观察到任何错误或特定行为？

@JoinColumn(name = "AuthorID", referencedColumnName = "AuthorID")
@ManyToOne(optional = false, cascade=CascadeType.MERGE)
private Author authorID;