Question

我开发了一个应用程序JAVA + Spring Boot + ThymeLeaf（简单易用的前端仅用于测试）。我有简单的域类播放器：

@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;

}

我想在＆＃34; service＆＃34;中计算玩家年龄。类。

问题是：如何将这些信息传递给前端？

控制器方法如下所示：

@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（生日日期没有年龄）。

我不想存储每个玩家的数据库年龄值 - 很明显。

我应该向控制器添加另一个：model.addAttribute（）;有关年龄的信息？（即使对我来说它看起来也不好）

我正在寻找智能解决方案，遵守清洁代码和MVC的规则。如果你能帮我找到好的解决方案，我很高兴，谢谢。

编辑：我只创建了AgeCalculator类：

@Component
@Data
public class AgeCalculator {

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

修改后的控制器：

@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: Exception evaluating SpringEL expression: "ageCalculator.calculateAge(player.birthdayDate)"

我的代码出了什么问题？

Answer 1

我首选的方法是向getAge()类添加Player方法。然后在前端，它看起来像这样：

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

如果您不想修改Player类，可以使用calculateAge(LocalDate birthday)方法创建一个帮助对象，然后将其添加到模型中并按以下方式调用它：

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

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

Answer 2

您可以在javascript中添加完整对象或部分内容，并像纯值一样使用它：

<script type="text/javascript" th:inline="javascript">

    /*<![CDATA[*/
    var some_data =/*[[${data}]]*/;
    /*]]>*/

</script>

这是将参数从spring控制器传递到前端的好方法。

Answer 3

好的，谢谢你的所有重播。这个问题的完整解决方案。

控制器：

@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";
    }

年龄计算器：

@Component
@Data
public class AgeCalculator {

    private LocalDate fromStringToLocalDate(String localDateString) {

        DateTimeFormatter inputFormat = DateTimeFormatter.ofPattern("MM/dd/yyyy");

        return LocalDate.parse(localDateString, inputFormat);
    }

    public int calculateAge(String birthDate) {
        if (birthDate != null) {
            return Period.between(fromStringToLocalDate(birthDate), LocalDate.now()).getYears();
        } else {
            return 0;
        }
    }
}

玩家域类：

@Entity
@Setter
@Getter
@EqualsAndHashCode(exclude = {"events"})
public class Player {
    (...)
    private String birthdayDate;
}

Thymeleaf代码：

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

如何转移信息，反对百里香

3 个答案: