Question

我实现了两个类，即User.java和UserDetail.java，并且我在它们之间创建了一对一映射，片段是

User.java

@Entity
@Table(name="user")
public class User {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private int id;
@Column(name="fname")
private String fname;
@Column(name="sname")
private String sname;
@Column(name="lname")
private String lname;
@Column(name="gender")
private String gender;
@Column(name="dob")
private String dob;
@Column(name="email")
private String email;
@Column(name="phone")
private String phone;
@Column(name="learningcenter")
private String learningcenter;
@Column(name="country")
private String country;
@Column(name="countryoforigin")
private String countryoforigin;

public String getCountryoforigin() {
    return countryoforigin;
}

public void setCountryoforigin(String countryoforigin) {
    this.countryoforigin = countryoforigin;
}

@OneToOne(cascade = CascadeType.ALL)
@JoinColumn(name="user_detail_id")
private UserDetail userDetail;

UserDetail.java

@Entity
@Table(name="user_detail")
public class UserDetail {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Column(name="id")
private int id;
@Column(name="first_language")
private String first_language;
@Column(name="second_language")
private String second_language;
@Column(name="levelofenglish")
private String levelofenglish;
@Column(name="levelofenglishyesorno")
private String levelofenglishyesorno;
@Column(name="levelofinternet")
private String levelofinternet;
@Column(name="cos1")
private String cos1;
@Column(name="cos2")
private String cos2;
@Column(name="proof")
private String proof;
@Column(name="yesq")
private String yesq;
@Column(name="certi1")
private String certi1;
@Column(name="employee")
private String employee;
@Column(name="oldornew")
private String oldornew;
@Column(name="vol")
private String vol;
@Column(name="commitments")
private String commitments;
@Column(name="profession")
private String profession;

public String getLevelofenglishyesorno() {
    return levelofenglishyesorno;
}

public void setLevelofenglishyesorno(String levelofenglishyesorno) {
    this.levelofenglishyesorno = levelofenglishyesorno;
}

@Column(name="howuknow")
private String howuknow;
@Column(name="othercomments")
private String othercomments;
@Column(name="expectation")
private String expectation;
@Column(name="status")
private String status;

@OneToOne(mappedBy = "userDetail")
private User user;

public User getUser() {
    return user;
}

public void setUser(User user) {
    this.user = user;
}

我已经创建了所有数据库表并创建了register.jsp页面以获取所有内容并将其传递给控制器 RegisterController.java

SessionFactory sessionFactory=new Configuration().configure("hibernate.cfg.xml")
                                                        .addAnnotatedClass(User.class)
                                                        .addAnnotatedClass(UserDetail.class).buildSessionFactory();
        Session session=sessionFactory.getCurrentSession();
        boolean flag=false;
        try
        {
           User user=new User(fname.toUpperCase(),sname.toUpperCase(),lname.toUpperCase(),gender,dob,email,phone,learningcenter,country,countryoforigin);
           UserDetail userDetail=new UserDetail(first_language,second_language,levelofenglish,levelofenglishyesorno,levelofinternet,cos1,cos2,
                                                 proof,yesq,certi1,employee,oldornew,vol,commitments,profession,howuknow,othercomments,expectation,"null");
           user.setUserDetail(userDetail);
           session.beginTransaction();
           session.save(user);
           userDetail.setUser(user);
           int id=user.getId();
           System.out.println(id+"is generated");

           List<User> userList=(List<User>)session.createQuery("from User u where u.id=:id")
                                                    .setParameter("id",id).list();
           for(User u:userList)
           {
               System.out.println(u.toString());
               flag=true;

           }
           model.addAttribute("user",user);
           model.addAttribute("userDetail",userDetail);
            session.getTransaction().commit();
           session.close();
        }
        catch (Exception e)
        {
            System.out.println(e);
        }

        if(flag)
        {
            return "success";
        }
        else
        {
            return "failure";
        }

执行该应用程序后，我能够注册该用户，以便它反映在数据库表中。我想知道的是通过jsp代码获取User和UserDetail的数据，但我无法获取userDetail内容

<div class="jumbotron text-xs-center">
    <c:forEach var="item" items="${user}">
    <h1 class="display-3">Login Successfull!${item.fname}</h1>
        ${item}
    </c:forEach>
</div>

在上述情况下，我可以获取“ user”，但不能获取“ userDetail”。我想在JSP代码中获取用户以及userDetail。请帮助

Answer 1

在代码中，您正在设置要创建的用户和用户详细信息，而不是从数据库中获取用户的详细信息。

 User user=new User(fname.toUpperCase(),sname.toUpperCase(),lname.toUpperCase(),gender,dob,email,phone,learningcenter,country,countryoforigin);
           UserDetail userDetail=new UserDetail(first_language,second_language,levelofenglish,levelofenglishyesorno,levelofinternet,cos1,cos2,
                                                 proof,yesq,certi1,employee,oldornew,vol,commitments,profession,howuknow,othercomments,expectation,"null");
           user.setUserDetail(userDetail);
           session.beginTransaction();
           session.save(user);
           userDetail.setUser(user);
           int id=user.getId();
           System.out.println(id+"is generated");

           List<User> userList=(List<User>)session.createQuery("from User u where u.id=:id")
                                                    .setParameter("id",id).list();
           for(User u:userList)
           {
               System.out.println(u.toString());
               flag=true;

           }
           model.addAttribute("user",user);
           model.addAttribute("userDetail",userDetail);

使用以下代码检查：

<div class="jumbotron text-xs-center">
    <c:forEach var="item" items="${user}">
    <h1 class="display-3">Login Successfull!${item.userDetail}</h1>
        ${item}
    </c:forEach>
</div>

无法以一对一映射的方式从实体中获取数据

1 个答案: