Hibernate：父子关系数据结构 [英] Hibernate: Parent and Child relationship data structure
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问题描述
源表
文件夹表： -
folder_id,folder_name,parent_id
---------------------------------
1,7-Zip,NULL
2,7z,1
3,Lang,1
文件表： -
file_id,file_name,folder_id
---------------------------------
1,7-zip.chm,1
2,7-zip.dll,1
3,7z.dll,3
4,af.txt,3
当我插入数据时，数据结构如下（DS的大小为1）
when i inserted data, the data structure was like below (Size of DS is 1)
[1,7-Zip,
childFolders[[2,7z],[3,Lang,childFolders[], childFiles[[3,7z.dll],[4,af.txt]]]],
childfiles[[1,7-zip.chm],[2,7-zip.dll]]]
从数据库检索数据那么我得到这样的东西（DS的大小是3）
when retrieved the data from the data base then I get something like this.(Size of DS is 3)
[1,7-Zip,
childFolders[[2,7z],[3,Lang,childFolders[], childFiles[[3,7z.dll],[4,af.txt]]]],
childfiles[[1,7-zip.chm],[2,7-zip.dll]]]
[2,7z,
childFolders[],
childfiles[]]
[3,Lang,
childFolders[],
childfiles[[3,7z.dll],[4,af.txt]]]
以下是我的工件
@Entity
@Table(name="Searchedfolder")
public class SearchedFolder implements Serializable, Comparable<SearchedFolder>{
/**
*
*/
private static final long serialVersionUID = -7373115811110399682L;
private long folderId;
private String folderName;
private String path;
private Date searchedTime;
private String description;
private Set<SearchedFile> childFiles = new HashSet<SearchedFile>();
private Set<SearchedFolder> childFolders = new TreeSet<SearchedFolder>();
private SearchedFolder parentFolder;
@Id
@Column(name="folder_id",insertable=true, updatable=true)
@GeneratedValue(strategy = GenerationType.AUTO)
public long getFolderId() {
return folderId;
}
public void setFolderId(long id) {
this.folderId = id;
}
@Column(name="path")
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
@Column(name="searched_time")
public Date getSearchedTime() {
return searchedTime;
}
public void setSearchedTime(Date searchedTime) {
this.searchedTime = searchedTime;
}
@Column(name="description")
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@Column(name="folder_name")
public String getFolderName() {
return folderName;
}
public void setFolderName(String folderName) {
this.folderName = folderName;
}
@OneToMany(targetEntity= SearchedFile.class, mappedBy="parentFolder", cascade={CascadeType.ALL}, fetch = FetchType.EAGER)
public Set<SearchedFile> getChildFiles() {
return childFiles;
}
public void setChildFiles(Set<SearchedFile> childFiles) {
this.childFiles = childFiles;
}
@OneToMany(mappedBy="parentFolder", cascade={CascadeType.ALL}, fetch=FetchType.EAGER)
public Set<SearchedFolder> getChildFolders() {
return childFolders;
}
public void setChildFolders(Set<SearchedFolder> folders) {
this.childFolders = folders;
}
@ManyToOne(cascade={CascadeType.ALL})
@JoinColumn(name="parent_id")
public SearchedFolder getParentFolder() {
return parentFolder;
}
public void setParentFolder(SearchedFolder parentFolder) {
this.parentFolder = parentFolder;
}
public int compareTo(SearchedFolder searchedFolder) {
return this.getFolderName().compareTo(searchedFolder.getFolderName());
}
}
@Entity
@Table(name="searchedfile" )
public class SearchedFile implements Serializable, Comparable<SearchedFile>{
/**
*
*/
private static final long serialVersionUID = -7474936475144364605L;
private long fileId;
private String fileName;
private Date searchedTime;
private String extension;
private String description;
private SearchedFolder parentFolder;
@Id
@Column(name="file_id",insertable=true, updatable=true)
@GeneratedValue(strategy = GenerationType.AUTO)
public long getFileId() {
return fileId;
}
public void setFileId(long fileId) {
this.fileId = fileId;
}
@Column(name="file_name")
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
@Column(name="searched_time")
public Date getSearchedTime() {
return searchedTime;
}
public void setSearchedTime(Date searchedTime) {
this.searchedTime = searchedTime;
}
@Column(name="extension")
public String getExtension() {
return extension;
}
public void setExtension(String extension) {
this.extension = extension;
}
@Column(name="description")
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
@ManyToOne(targetEntity= SearchedFolder.class, cascade={CascadeType.ALL}, fetch = FetchType.EAGER)
@NotFound(action = NotFoundAction.IGNORE)
@JoinColumn(name="folder_id")
public SearchedFolder getParentFolder() {
return this.parentFolder;
}
public void setParentFolder(SearchedFolder parentFolder) {
this.parentFolder = parentFolder;
}
public int compareTo(SearchedFile searchedFile) {
return this.getFileName().compareTo(searchedFile.getFileName());
}
}
DAO文件： -
DAO File : -
@Repository
public class SearchedFolderDAOImpl implements SearchedFolderDAO {
@Autowired
private SessionFactory schedulerSessionFactory;
@Override
public void addSearchedData(SearchedFolder searchedFolder) {
Session session = schedulerSessionFactory.openSession();
if(session == null){
schedulerSessionFactory.openSession();
}
try{
session.save(searchedFolder);
}catch (HibernateException e) {
e.printStackTrace();
}finally {
session.close();
}
}
@Override
public List<SearchedFolder> getSearchedData() {
Criteria ctria = schedulerSessionFactory.getCurrentSession().createCriteria(SearchedFolder.class)
.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
.setFetchMode("childFiles", FetchMode.SELECT);
List<SearchedFolder> folders = (List<SearchedFolder>) ctria.list();
return folders;
}
@Override
public void deleteSearchedData(Integer SearchedDataId) {
// TODO Auto-generated method stub
}
@Override
public List<SearchedFolder> getSearchedData(String folderName) {
// TODO Auto-generated method stub
return null;
}
}
服务文件： -
Service File:-
@Service("defaultSearchDataService")
public class SearchDataServiceImpl implements SearchDataService{
{System.out.println("defaultSearchDataService...");}
@Autowired
private SearchedFileDAO searchedFileDAO;
@Autowired
private SearchedFolderDAO searchedFolderDAO;
@Override
@Transactional(readOnly=false, timeout=300, propagation=Propagation.REQUIRES_NEW)
public void saveFiles(List<SearchedFile> files) {
// TODO Auto-generated method stub
}
@Override
@Transactional(readOnly=true, timeout=300, propagation=Propagation.REQUIRED)
public List<SearchedFile> getFiles() {
// TODO Auto-generated method stub
return null;
}
@Override
@Transactional(readOnly=true, timeout=300, propagation=Propagation.REQUIRES_NEW)
public List<SearchedFolder> getFolders() {
List<SearchedFolder> folders = searchedFolderDAO.getSearchedData();
return folders;
}
@Override
@Transactional(readOnly=false,propagation=Propagation.REQUIRES_NEW, timeout=30)
public void addFolder(NewFolderForm newFolderForm) {
// TODO Auto-generated method stub
}
@Override
@Transactional(readOnly=false, timeout=300, propagation=Propagation.REQUIRED)
public void saveFolder(SearchedFolder searchedFolder) {
searchedFolderDAO.addSearchedData(searchedFolder);
}
@Override
public void saveFolder(Set<SearchedFolder> directory) {
Iterator<SearchedFolder> searchedFolderIterator = directory.iterator();
while(searchedFolderIterator.hasNext()){
SearchedFolder searchedFolder = searchedFolderIterator.next();
saveFolder(searchedFolder);
}
}
}
Question1：为什么插入和检索DataStructures是不同的？
Question1 : Why inserting and retrieving DataStructures are different?
问题2：如何解决这个问题
Question2 : How to fix this issue
推荐答案
您正在插入3个文件夹。当你插入这个：
You are inserting 3 folders. When you insert this:
[1,7-Zip,
childFolders[[2,7z],[3,Lang,childFolders[], childFiles[[3,7z.dll],[4,af.txt]]]],
childfiles[[1,7-zip.chm],[2,7-zip.dll]]]
您正在同时创建文件夹1,2和3。文件夹2没有文件或子文件夹。但是，文件夹3有3个文件。
当您尝试使用 getFolders 检索此信息时，您可以同时检索所有三个文件夹。这就是 getSearchedData（）。
You are creating Folder 1, 2 and 3 at the same time. Folder 2 hasn't files or subfolders. However, Folder 3 has 3 files.
When you try to retrieve this information you have with getFolders you retrieve all three folders at the same time. That's what getSearchedData() does.
您可以通过在类<$ c中创建一个新方法来解决它$ c> SearchedFolder
@Override
public List<SearchedFolder> getSearchedFolder(Long folderId) {
Criteria ctria = schedulerSessionFactory.getCurrentSession().createCriteria(SearchedFolder.class)
.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY)
.setFetchMode("childFiles", FetchMode.SELECT);
List<SearchedFolder> folders = (List<SearchedFolder>) ctria.list();
ctria.add(Restrictions.eq("folderId", folderId));
return folders;
}
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