春季休眠ManyToMany

我有2个表，视频，VIDEOCATEGORY和加入表VIDEO2VIDEOCATEGORY。我正在尝试做很多注释。编译时没有错误或警告。春季休眠ManyToMany

数据库在开始时为空。我试图坚持视频实体（与VideoCategory列表）..在这个时候是所有的声明。新视频被添加到数据库。一些新的类别也被添加。然后，我尝试使用新的独特类别添加新视频...也是正确的。问题是当我尝试添加新的视频与数据库中已经存在的类别。在这次尝试之前，我有2个记录在VIDEO2VIDEOCATEGORY（“cat1”，3）和（“cat2”，3）...尝试后应该有2个新记录 - （“cat1”，4）和（“cat2”，4 ）和2个现有的（“cat1”，3）和（“cat2”，3），但那些旧的不在DB中。他们被2条新纪录改写。

如何解决？我的代码：



    import java.io.Serializable; 
    import java.util.List; 

    import javax.persistence.Column; 
    import javax.persistence.Entity; 
    import javax.persistence.FetchType; 
    import javax.persistence.Id; 
    import javax.persistence.JoinColumn; 
    import javax.persistence.JoinTable; 
    import javax.persistence.ManyToMany; 

    import org.hibernate.annotations.Cascade; 


    @Entity 
    public class VideoCategory implements Serializable{ 

     private static final long serialVersionUID = -722840296120424003L; 

     @Id 
     @Column(name = "id", unique = true, nullable = false) 
     private String id; 


     @ManyToMany(fetch=FetchType.EAGER) 
     @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE) 
     @JoinTable(name = "video2videocategory", 
       joinColumns = {@JoinColumn(name = "cat_id")}, inverseJoinColumns =  @JoinColumn(name = "vid_id")) 
      private List videos; 


     public VideoCategory(){ 
     } 

     public VideoCategory(String id) { 
      super(); 
      this.id = id; 
     } 
     public String getId() { 
      return id; 
     } 
     public void setId(String id){ 
      this.id = id; 
     } 
     public List getVideos() { 
      return videos; 
     } 
     public void setVideos(List videos) { 
      this.videos = videos; 
     } 

     @Override 
     public String toString() { 
      return "VideoCategory [id=" + id + ", videos=" + videos + "]"; 
     } 
    } 


    import java.io.Serializable; 
    import java.util.Date; 
    import java.util.List; 

    import javax.persistence.Column; 
    import javax.persistence.Entity; 
    import javax.persistence.EnumType; 
    import javax.persistence.Enumerated; 
    import javax.persistence.GeneratedValue; 
    import javax.persistence.GenerationType; 
    import javax.persistence.Id; 
    import javax.persistence.JoinTable; 
    import javax.persistence.ManyToMany; 
    import javax.persistence.SequenceGenerator; 
    import javax.persistence.JoinColumn; 

    import org.hibernate.annotations.Cascade; 



    @Entity 
    @SequenceGenerator(
     name="VID_SEQ_GEN", 
     sequenceName="VIDSEQ", 
     allocationSize=1 
    ) 
    public class Video implements Serializable { 

     private static final long serialVersionUID = 2284488937952510797L; 

     @Id @GeneratedValue(strategy = GenerationType.SEQUENCE, generator="VID_SEQ_GEN") 
     @Column(name = "id", unique = true, nullable = false) 
     private Long id; 

     @Column(name = "title", unique = false, nullable = false) 
     private String title; 

     @Column(name = "video_path", unique = false, nullable = false) 
     private String videoPath; 

     @Column(name = "video_type", unique = false, nullable = false) 
     @Enumerated(value=EnumType.STRING) 
     private VideoType videoType; 

     @Column(name = "creation_date", unique = false, nullable = false) 
     private Date creationDate; 

     @ManyToMany 
     @Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE) 
     @JoinTable(name = "video2videocategory", 
       joinColumns = {@JoinColumn(name = "vid_id")}, inverseJoinColumns = @JoinColumn(name = "cat_id")) 
     private List categories; 



     public Video(){ 
     } 


     public Long getId() { 
      return id; 
     } 
     public void setId(Long id) { 
      this.id = id; 
     } 
     public String getTitle() { 
      return title; 
     } 
     public void setTitle(String title) { 
      this.title = title; 
     } 
     public String getVideoPath() { 
      return videoPath; 
     } 
     public void setVideoPath(String videoPath) { 
      this.videoPath = videoPath; 
     } 
     public VideoType getVideoType() { 
      return videoType; 
     } 
     public void setVideoType(VideoType videoType) { 
      this.videoType = videoType; 
     } 
     public Date getCreationDate() { 
      return creationDate; 
     } 
     public void setCreationDate(Date creationDate) { 
      this.creationDate = creationDate; 
     } 
     public List getCategories() { 
      return categories; 
     } 

     public void setCategories(List categories) { 
      this.categories = categories; 
     } 

     @Override 
     public String toString() { 
      return "Video [id=" + id + ", creationDate=" 
        + creationDate + ", title=" + title 
        + ", videoPath=" + videoPath + ", videoType=" + videoType + "]"; 
     } 
    }

我曾经尝试都JPA和Hibernate标注。

请帮忙。

来源

2012-03-05 falconseye

显示你的'保存（）'方法好像正在更新它不建立新one.When你认为要添加新的'做Video'确定它实际上是视频的新实例，而不是现有的实例。你的映射是正确的问题是在'save（）'或者更可能是你认为是一个新的视频实例，而实际上它不是。 – Shahzeb 2012-03-05 23:54:15

public void save（视频视频）{ \t \t getHibernateTemplate（）。save（video）; \t \t} – falconseye 2012-03-06 00:11:36

我正在创建视频的新实例，没有ID，我试着保存。 – falconseye 2012-03-06 00:14:09

错误可能是您将双方的父母定义为多对多关系。一边应该是孩子，像这样：

@ManyToMany(mappedBy = "categories") // in the class VideoCategory

来源

2012-03-06 08:59:58

春季休眠ManyToMany

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