selectボタンで指定した値がdbに登録されない

selectボタンでプルダウン式で表示した値を選択後、登録するのですがdbに挿入されずnullのままになってしまいます。
やり方としてはcontrollerで入れたい値を指定してviewで表記、その後は画面で選択しdb挿入の流れで考えてます。
keyかvalueどちらが入っても構いません。

controller

  private Map<String,String> getGenre(){
    Map<String, String> selectMap = new LinkedHashMap<String, String>();
    selectMap.put("1", "小説");
    selectMap.put("2", "経営・戦略");
    selectMap.put("3", "政治・経済");
    selectMap.put("4", "IT");
    selectMap.put("5", "自己啓発");
    selectMap.put("6", "タレント本");
    selectMap.put("7", "その他");
    return selectMap;
  } 
  

  @GetMapping("new")
  public String newBook(Model model) {
    model.addAttribute("selectBooks",getGenre());
      return "books/new";
  }

repository

  @Override
  public List<Book> findAll() {

    String sql = "SELECT book.id, title, author, publisher, buy_date, release_date, genre, over_view FROM Book";
    
    return jdbcTemplate.query(sql,new BeanPropertyRowMapper<Book>(Book.class));
    
  }


    @Override
    public Optional<Book> findOne(int id) {
      
      String sql = "SELECT book.id, title, author, publisher, buy_date, release_date, genre, over_view FROM book "
        + "WHERE id = ?";
        
      Map<String, Object> result = jdbcTemplate.queryForMap(sql, id);

        Book book = new Book();
        book.setId((int)result.get("id"));
        book.setTitle((String)result.get("title"));
        book.setAuthor((String)result.get("author"));
        book.setPublisher((String)result.get("publisher"));
        book.setBuyDate((Date)result.get("buy_date"));
        book.setReleaseDate((Date)result.get("release_date"));
        book.setGenre((String)result.get("Genre"));
        book.setOverView((String)result.get("over_view"));
        System.out.println(result);
        //bookをOptionalでラップする
        Optional<Book> bookOpt = Optional.ofNullable(book);
        return bookOpt;
	}

      @Override
      public void insert(Book book) {
        jdbcTemplate.update("INSERT INTO book(genre) VALUES(?)",
        book.getGenre() );
      }

      @Override
      public void save(Book book) {
        jdbcTemplate.update("INSERT INTO book(title, author, publisher, buy_date, release_date, genre, over_view) VALUES(?, ?, ?, ?, ?, ?, ?)",
        book.getTitle(), book.getAuthor(), book.getPublisher(), book.getBuyDate(), book.getReleaseDate(), book.getGenre(), book.getOverView() );
      }
      
      
      @Override
      public int update(Book book) {
        return   jdbcTemplate.update("UPDATE book SET title = ?, author = ?, publisher = ?, buy_date = ?, release_date = ?, genre = ?, over_view = ? WHERE id = ?",
        book.getTitle(), book.getAuthor(), book.getPublisher(), book.getBuyDate(), book.getReleaseDate(), book.getGenre(),book.getOverView(), book.getId() );
      }

      @Override
      public int delete(int id) {
        return jdbcTemplate.update("DELETE FROM book WHERE id = ?", id);
      }

    }

view

<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
  <head>
    <meta charset="utf-8" />
    <title>New Player - baseball</title>
    <link rel="stylesheet" href="/css/bootstrap.css" />
    <script src="/js/jquery.js"></script>
    <script src="/js/bootstrap.js"></script>
  </head>
  <body>
    <div class="container">
      <h1>New Player</h1>
      <!-- <body th:object="${book}"> -->

      <form th:action="@{/books}" th:method="post">
        <div class="form-group">
          <label class="control-label">タイトル</label>
          <input class="form-control" type="text" name="title" />
        </div>
        <div class="form-group">
          <label class="control-label">著者</label>
          <input class="form-control" type="text" name="author" />
        </div>
        <div class="form-group">
          <label class="control-label">出版社</label>
          <input class="form-control" type="text" name="publisher" />
        </div>
        <div class="form-group">
          <label class="control-label">購入日</label>
          <input class="form-control" type="date" name="buyDate" />
        </div>
        <div class="form-group">
          <label class="control-label">発売日</label>
          <input class="form-control" type="date" name="releaseDate" />
        </div>

        <div class="form-group">
          <label class="control-label">ジャンル</label>
          <select>
            <option value="">---</option>
            <option th:each="book : ${selectBooks}" th:value="*{book.value}"
             th:text="*{book.value}" th:selected="*{book.value} == *{selectBooks}"></option>
          </select>
          
        </div>

        <div class="form-group">
          <label class="control-label">概要</label>
          <input class="form-control" type="text" name="overView" />
        </div>
        <button class="btn btn-default" type="submit">作成</button>
      </form>

      <div class="pull-right">
        <a class="btn btn-link" href="/books">一覧画面へ</a>
      </div>
    </div>
  </body>
</html>

原因はrepositoryのdb処理がうまくいってないと考えていて調査してます。
何方かのお力を頂ければと思います。
恐縮ですが、何卒よろしくお願いいたします。