Question

我有3个对象：User，Comment和StatusUpdate（新闻）。这是用户......

@Entity
@Table(name = "users")
@PasswordMatch(message = "{register.repeatpassword.mismatch}")
public class SiteUser {

@Id
@GeneratedValue(strategy = GenerationType.AUTO)
@Column(name = "id")
private Long id;

@Column(name = "email", unique = true)
@Email(message = "{register.email.invalid}")
@NotBlank(message = "{register.email.invalid}")
private String email;

@Transient
@Size(min = 5, max = 15, message = "{register.password.size}")
private String plainPassword;

@Column(name = "password", length = 60)
private String password;

@Column(name = "enabled")
private Boolean enabled = false;

@NotNull
@Column(name = "firstname", length = 20)
@Size(min = 2, max = 20, message = "{register.firstname.size}")
private String firstname;

@NotNull
@Column(name = "surname", length = 25)
@Size(min = 2, max = 25, message = "{register.surname.size}")
private String surname;

@Transient
private String repeatPassword;

@Column(name = "role", length = 20)
private String role;

public SiteUser() {

}

状态更新（您可以将其称为新闻或文章）。那个网站用户是创建该文章的用户。

@Entity
@Table(name = "status_update")
public class StatusUpdate {

@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@Size(min=5, max=255, message="{addstatus.title.size}")
@Column(name = "title")
private String title;

@Size(min=5, max=5000, message="{addstatus.text.size}")
@Column(name = "text")
private String text;

@Column(name = "added")
@Temporal(TemporalType.TIMESTAMP)
@DateTimeFormat(pattern="yyyy/MM/dd hh:mm:ss")
private Date added;

@OneToOne(targetEntity = SiteUser.class)
@JoinColumn(name="user_id")
private SiteUser siteUser;

@PrePersist
protected void onCreate() {
    if (added == null) {
        added = new Date();
    }
}

public StatusUpdate() {

}

可以由任何注册用户完成的评论，对吗？正如您将注意到，Comment没有User对象以避免循环引用。

@Entity
@Table(name = "comments")
public class Comment {

@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private Long id;

@ManyToOne
@JoinColumn(name = "statusupdateid")
private StatusUpdate statusUpdate;

@Column(name = "commenttext")
private String commenttext;

@Column(name = "commentdate")
@Temporal(TemporalType.TIMESTAMP)
@DateTimeFormat(pattern = "yyyy/MM/dd hh:mm:ss")
private Date commentdate;

@Column(name = "userid")
private Long userid;


public Comment() {
}

现在我想在我的JSP中显示一篇文章，其中包含所有相关注释，每个注释都属于不同的用户。我可以使用HashMap来关联用户及其评论吗？我不知道怎么做。

@RequestMapping(value ="/viewonestatus/{id}")
public ModelAndView viewOneStatus(@PathVariable("id") Long id) {

    StatusUpdate status = statusUpdateService.get(id);

    int countComments = commentService.countStatusComments(status);

    List<Comment> comments = commentService.readAllComments(status);

    ModelAndView modelAndView = new ModelAndView();

    for (Comment comment: comments){

        SiteUser user = userService.get(comment.getUserid());

        modelAndView.getModel().put("user", user);

    }

    modelAndView.getModel().put("commentscounter", countComments);
    modelAndView.getModel().put("status", status);
    modelAndView.getModel().put("comments", comments); //!!

    modelAndView.setViewName("app.viewonestatus");

    return modelAndView;
}

如您所料，当我的JSP只显示所有注释的一个用户（最后一个）时，但我无法将所有注释与相应的用户关联

<table class="table table-hover">
    <c:forEach var="comment" items="${comments}">
    <tr>
        <td>

    <div class="col-sm-2 sm-margin-bottom-40">
        <img class="img-responsive profile-img margin-bottom-20" id="profilePhotoImage" src="/profilephoto/${comment.userid}" />
    </div>
                                                <h4> 
            ${user.firstname} ${user.surname} 
            <span> 
              <!--  <span>${counterUserMap[comment.key]}</span> -->
            5 hours ago / <a href="#">Reply</a>
            </span>
        </h4>
        <p>
            <fmt:formatDate pattern="EEEE d MMMM y 'at' H:mm:ss" value="${comment.commentdate}" />
        </p>
        <p>${comment.commenttext}</p>
    </td>
</tr>
</c:forEach>

我不想使用JSON。我正在考虑一个包含所有内容的匿名课程。好吧，我对你的想法持开放态度。感谢。

Answer 1

Shokulei回答是解决方案：

由于您拥有userid，因此可以使用@ManyToOne批注对其进行链接。这将是最理想的方式。但如果你真的不想链接它们，那么你可以创建一个新的@Transient SiteUser siteUser; Comment类中的属性。然后在你的for循环中，你可以使用comment.setSiteUser（user）;而不是modelAndView.getModel（）。put（“user”，user）;.希望这会有所帮助。

谢谢Shokulei

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