java - 如何传递信息，反对thymeleaf

Question

我正在开发一个应用程序JAVA + Spring Boot + ThymeLeaf(简单且简单的前端仅用于测试)。 我有简单的域类 Player:

@Entity
@Setter
@Getter
@EqualsAndHashCode(exclude = {"events"})
public class Player {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String playerName;
    private String playerLastName;
    private String playerNickname;
    private String playerEmailAddress;
    private String playerTelephoneNumber;

    @ManyToMany(mappedBy = "players", fetch = FetchType.EAGER)
    private Set<Event> events = new HashSet<>();

    @Enumerated(value = EnumType.STRING)
    private FavouritePosition favouritePosition;
    private LocalDate birthdayDate;

}

我想计算“服务”类别中的玩家年龄。

问题是:如何将这些信息传输到前端？

Controller 方法如下所示:

@RequestMapping("/event/{eventId}/player/{playerId}/show")
    public String showPlayerForSpecificTeam(Model model, @PathVariable String eventId, @PathVariable String playerId) {

        model.addAttribute("player", playerService.getPlayerByEventIdAndPlayerId(Long.valueOf(eventId), Long.valueOf(playerId)));

        return "event/player/showPlayerForSpecifiedEvent";
    }

方法getPlayerByEventIdAndPlayerId(Long.valueOf(eventId), Long.valueOf(playerId))返回Player对象(没有年龄，只有生日日期)。

我不想在数据库中存储每个玩家的年龄值 - 这是显而易见的。

我应该向 Controller 添加另一个:model.addAttribute();有年龄信息吗？ (即使对我来说也看起来不太好)

我正在寻找聪明的解决方案，遵守干净代码和 MVC 的规则。 如果您能帮助我找到好的解决方案，我将很高兴，谢谢。

编辑: 我刚刚创建了 AgeCalculator 类:

@Component
@Data
public class AgeCalculator {

    public Integer calculateAge(Player player) {
        return Years.yearsBetween(player.getBirthdayDate(), new LocalDate()).getYears();
    }
}

修改后的 Controller :

@RequestMapping({"player/{playerId}/show"})
    public String getPlayerById(Model model, @PathVariable String playerId) {

        model.addAttribute("player", playerService.getPlayerById(Long.valueOf(playerId)));
        model.addAttribute("ageCalculator", new AgeCalculator());
        return "event/player/showPlayerById";
    }

在 thymeleaf 中我使用:

<p th:text="${ageCalculator.calculateAge(player)}">Here will be a Player age</p>

但我收到错误:org.thymeleaf.exceptions.TemplateProcessingException:评估 SpringEL 表达式时出现异常:“ageCalculator.calculateAge(player.birthdayDate)”

我的代码有什么问题吗？

Answer 1

我的首选方法是添加 getAge()方法Player类(class)。那么在前端，它看起来像这样:

<span th:text="${player.age}" />

如果您不想修改 Player类，您可以使用 calculateAge(LocalDate birthday) 创建一个辅助对象方法，然后将其添加到模型中并像这样调用它:

Java:model.addAttribute("helper", new BirthdayHelper());

thymeleaf :<span th:text="${helper.calculateAge(player.birthdayDate)}" />