Java 春天冬眠很多
我有两个表,视频,视频类别和加入表VIDEO2VIDEOCATEGORY。 我正在尝试进行多对多的注释。编译中没有错误或警告 数据库开头为空。我试图保持视频实体(与视频类别列表)…在这个时候都是正确的。新的视频被添加到数据库中。还添加了一些新类别。然后我尝试添加新的视频和新的独特的类别…正确的,以及。问题是当我尝试添加新视频时,DB中已经存在类别。在此尝试之前,我在VIDEO2VIDEOCATEGORY(“cat1”,3)和(“cat2”,3”)中有2条记录。尝试之后,应该有2条新记录-“cat1”,4)和(“cat2”,4)以及2条现有记录(“cat1”,3)和(“cat2”,3),但旧记录不在DB中。他们被两张新唱片改写了 如何解决? 我的代码:Java 春天冬眠很多,java,spring,hibernate,jakarta-ee,many-to-many,Java,Spring,Hibernate,Jakarta Ee,Many To Many,我有两个表,视频,视频类别和加入表VIDEO2VIDEOCATEGORY。 我正在尝试进行多对多的注释。编译中没有错误或警告 数据库开头为空。我试图保持视频实体(与视频类别列表)…在这个时候都是正确的。新的视频被添加到数据库中。还添加了一些新类别。然后我尝试添加新的视频和新的独特的类别…正确的,以及。问题是当我尝试添加新视频时,DB中已经存在类别。在此尝试之前,我在VIDEO2VIDEOCATEGORY(“cat1”,3)和(“cat2”,3”)中有2条记录。尝试之后,应该有2条新记录-“cat
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 + "]";
}
}
我尝试了jpa和hibernate注释
请帮助。错误可能是您将多对多关系定义为双方的父关系。 一边应该是孩子,像这样:
@ManyToMany(mappedBy = "categories") // in the class VideoCategory
显示您的
save()
方法似乎是在更新它,而不是创建新的。当您认为要添加新视频时,请确保它实际上是视频的新实例,而不是现有实例。您的映射是正确的问题可能出现在save()
中,或者更可能出现在您认为新的视频实例中,而实际情况并非如此。public void save(video video){getHibernateTemplate().save(video);}我正在创建一个新的视频实例,没有id,我尝试保存这个实例。