Hibernate - 一对多关系

Question

我正在使用Hibernate一对多的关系来保存和获取我的数据，读取数据时可以获取机构值，但是在保存机构值到数据库时无法插入。

有人能帮我知道我做错了什么吗？

在我的jsp中，我使用以下代码来显示机构下拉列表：

<div class = "clearfix"></div>
                        <div class="form-group">
                            <label for="agency" class="col-sm-2 control-label">Agency</label>
                            <div class="col-sm-10">                             
                                <form:select path="agencies" class = "form-control">
                                    <c:forEach items="${agencies}" var="agency">                                        
                                       <option value="${agency.agency_id}" >${agency.name}</option>                                        
                                    </c:forEach>
                                </form:select>                          
                            </div>
                        </div>

我的活动实体就像

package com.nativeunlock.dto;

import java.io.Serializable;

import javax.persistence.*;
import org.hibernate.annotations.Parameter;
import javax.validation.constraints.Digits;
import javax.validation.constraints.NotNull;

import org.hibernate.annotations.GenericGenerator;

import lombok.Getter;
import lombok.Setter;


@SuppressWarnings("serial")
@NamedQueries({
    @NamedQuery(
            name = CampaignEntity.GET_CAMPAIGNS_QUERY,
            query = "from CampaignEntity campaign"
    ),
    @NamedQuery(
            name = CampaignEntity.DELETE_CAMPAIGNS_QUERY,
            query = "DELETE FROM CampaignEntity campaign WHERE campaign.campaign_id = :campaign_id"
    ),
    @NamedQuery(
            name = CampaignEntity.GET_CAMPAIGN_QUERY,
            query = "FROM CampaignEntity campaign WHERE campaign.campaign_id = :campaign_id"
    )    
})

@Entity
@Table(name = "campaign")
public class CampaignEntity implements Serializable {

    public static final String GET_CAMPAIGNS_QUERY ="getCampaignList";
    public static final String DELETE_CAMPAIGNS_QUERY ="deleteCampaignList";
    public static final String GET_CAMPAIGN_QUERY = "getCampaign";

    @Id
    @Getter
    @Setter
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "campaign_id", unique = true, nullable = false)
    private int campaign_id;

    @Getter
    @Setter
    @Column(name = "name", unique = true)
    //@NotEmpty(message="Name field is mandatory.")
    private String name;


    @Getter
    @Setter
    @Column(name = "no_of_views")
    //@NotNull(message="No. of Views field is mandatory.")
    private int no_of_views;

    @Getter
    @Setter
    @Column(name = "video_url") 
    //@NotEmpty(message="Video URL field is mandatory.")
    private String video_url;

    @Getter
    @Setter
    @Column(name = "start_date")    
    //@NotEmpty(message="Start Date field is mandatory.")
    private String  start_date;

    @Getter
    @Setter
    @Column(name = "end_date")
    //@NotEmpty(message="End Date field is mandatory.")
    private String end_date;

    @Getter
    @Setter
    @Column(name = "click_to_play")
    //@NotNull(message="Click to play field is mandatory.")
    private int click_to_play;

    @Getter
    @Setter
    @Column(name = "frequency")
    //@NotNull(message="Frequency field is mandatory.")
    private int frequency;

    @Getter
    @Setter
    @Column(name = "priority")
    @Digits(fraction = 0, integer = 100)
    //@NotNull(message="Priority field is mandatory.")
    private int priority;

    @Getter
    @Setter
    @Column(name = "divice")
    //@NotNull(message="Divice field is mandatory.")
    private int divice;

    @Getter
    @Setter
    @Column(name = "operating_system")
    //@NotNull(message="Operating system field is mandatory.")
    private int operating_system;   

    @Getter
    @Setter
    @Column(name = "google_analytics_id")
    @NotNull(message="Google analytics Id field is mandatory.")
    private String google_analytics_id;

    @Getter
    @Setter
    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "publisher_id")
    private PublisherEntity publishers;

    @Getter
    @Setter
    @ManyToOne
    @JoinColumn(name = "agency_id")
    private AgencyEntity agencies;

    @Override
    public String toString() {
        return "CampaignEntity [campaign_id=" + campaign_id + ", name=" + name
                + ", no_of_views=" + no_of_views + ", video_url=" + video_url
                + ", start_date=" + start_date + ", end_date=" + end_date
                + ", click_to_play=" + click_to_play + ", frequency="
                + frequency + ", priority=" + priority + ", divice=" + divice
                + ", operating_system=" + operating_system
                + ", google_analytics_id=" + google_analytics_id
                + ", publishers=" + publishers + ", agencies=" + agencies + "]";
    }           
}

我的机构实体就像是：

package com.nativeunlock.dto;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

import javax.persistence.*;

import lombok.Getter;
import lombok.Setter;


@SuppressWarnings("serial")
@NamedQueries({
    @NamedQuery(
            name = AgencyEntity.GET_AGENCIES_QUERY,
            query = "from AgencyEntity agnecy"
    )     
})

@Entity
@Table(name = "agency")
public class AgencyEntity implements Serializable {

    public static final String GET_AGENCIES_QUERY ="getAgencyList";

    @Id
    @Getter
    @Setter
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "agency_id", unique = true, nullable = false)
    private int agency_id;


    @Getter
    @Setter
    @Column(name = "name")  
    private String name;

    @OneToMany (mappedBy="agencies", cascade={CascadeType.PERSIST, CascadeType.REMOVE})
    @org.hibernate.annotations.Cascade( {org.hibernate.annotations.CascadeType.SAVE_UPDATE})
    private Set<CampaignEntity> campaigns = new HashSet<CampaignEntity>();

}

以下是插入记录的代码。

@Override
    public boolean saveCampaign(CampaignEntity campaignObj) {
        try{
            Session session=getCurrentSession();
            session.beginTransaction();
            session.saveOrUpdate(campaignObj);
            session.getTransaction().commit();
            return true;
        } catch(Exception e) {
            e.printStackTrace();
        }
        return false;
    }

感谢您的预先帮助。

- Anupam Sharma

---

你插入数据的代码在哪里？我们可能需要它。 - Paul Lo

保罗，我已经在问题中添加了代码。 - Anupam Sharma

您能否发布创建传递给saveCampaign()的CampaignEntity的代码？ - Alan Hay

Answer 1

你必须在CampaignEntity的agencies字段中也使用@Cascade注释。

@Getter
@Setter
@ManyToOne
@JoinColumn(name = "agency_id")
@org.hibernate.annotations.Cascade( {org.hibernate.annotations.CascadeType.SAVE_UPDATE})    
private AgencyEntity agencies;

- Maroš Tyrpák

---

是的，我做了那个，但仍然无法保存数据。 实际上，当我提交时，它会发送一个空值来代替机构。 - Anupam Sharma

Answer 2

尝试将session.beginTransaction()替换为session.getTransaction()，然后提交该事务。如果Spring正在管理您的事务，则该事务可能已经存在，您不需要自己启动另一个事务。

@Override
public boolean saveCampaign(CampaignEntity campaignObj) {
    try{
        Session session = getCurrentSession();
        session.getTransaction().begin();
        session.saveOrUpdate(campaignObj);
        session.getTransaction().commit();
        return true;
    } catch(Exception e) {
        e.printStackTrace();
    }
    return false;
}

- Predrag Maric