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Import and normalize XML using Hibernate

When importing xml into a database with Hibernate, is there a way to allow an attribute consisting of comma separated values ​​to populate related tables?

In this (somewhat confusing) example, I have an xml file, each line of which represents Person. A person has a Hobby property that contains a list of values ​​separated by commas. The Person-Hobby relationship is a lot for many. Actually, I have data to process the data.

When importing each person into the PEOPLE table, I would like to add each Hobby to the HOBBIES table (ignoring duplicates), and then add the mapping to the PEOPLE_HOBBIES table.

I installed the mapping files with bidirectional associations, and Hibernate seems to build the tables as I expected (see below for more details), but I don’t see what mechanism I can use to extract / populate HOBBIES and PEOPLE_HOBBIES when processing PEOPLE.

All help and / or RTFM links are welcome.

This is the file I am processing (people.xml):

<People>
  <Person Id="1" Name="Dave" Hobbies="drinking, walking"/>
  <Person Id="2" Name="Geoff" Hobbies="football, ballet"/>
  <Person Id="3" Name="Anne" Hobbies="walking, karate"/>
  <Person Id="4" Name="Frank" Hobbies="karate, cross-stitch"/>
</People>

Person.hbm.xml (xml decl exception):

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="name.seller.rich.hobby">  
  <class name="Person" node="Person" table="PEOPLE">
    <id name="id" node="@Id" column="PEOPLE_ID"/>
    <property name="name" node="@Name" column="NAME" type="string"/>
    <property name="hobbies" node="@Hobbies" column="HOBBIES" type="string"/>
    <set name="hobbiesSet" table="PEOPLE_HOBBIES">
      <key column="PEOPLE_ID"/>
      <many-to-many column="HOBBY" class="Hobby"/>
    </set>
  </class>
</hibernate-mapping>

Hobbies .hbm.xml:

<hibernate-mapping package="name.seller.rich.hobby">  
  <class name="Hobby" node="Hobby" table="HOBBIES">
    <id name="hobby" column="HOBBY" type="string"/>
    <set name="people" table="PEOPLE_HOBBIES" inverse="true">
      <key column="HOBBY"/>
      <many-to-many column="PEOPLE_ID" class="Person"/>
    </set>
  </class>
</hibernate-mapping>

This is the Person class, in the setHobbies () method, I populate the hobbiesSet with Hobby instances:

package name.seller.rich.hobby;

import java.util.HashSet;
import java.util.Set;

public class Person {

    private long id;

    private String name;

    private String hobbies;

    private Set hobbiesSet = new HashSet();

    public String getHobbies() {
        return hobbies;
    }

    public Set getHobbiesSet() {
        if (hobbiesSet == null) {
            hobbiesSet = new HashSet();
        }
        return hobbiesSet;
    }

    public long getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public void setHobbies(final String hobbies) {
        this.hobbies = hobbies;
    }

    public void setHobbiesSet(final Set hobbiesSet) {
        this.hobbiesSet = hobbiesSet;
    }

    public void setId(final long id) {
        this.id = id;
    }

    public void setName(final String name) {
        this.name = name;
    }
}

This is the code I use to process the file:

package name.seller.rich.hobby;

import java.io.File;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.io.SAXReader;
import org.hibernate.EntityMode;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.hibernate.tool.hbm2ddl.SchemaExport;

public class DataImporter {

    public static void main(final String[] args) {
        File baseDir = new File("C:\\workspaces\\hobby");
        DataImporter importer = new DataImporter();
        Configuration config = importer.setupDb(baseDir);

        if (config != null) {
            importer.importContents(new File(baseDir, "people.xml"), config);
        }
    }

    private void importContents(final File file, final Configuration config) {
        SessionFactory sessionFactory = config.buildSessionFactory();
        Session session = sessionFactory.openSession();    
        Transaction tx = session.beginTransaction();
        Session dom4jSession = session.getSession(EntityMode.DOM4J);

        SAXReader saxReader = new SAXReader();
        try {
            Document document = saxReader.read(file);

            List list = document.selectNodes("//Person");
            Iterator iter = list.iterator();

            while (iter.hasNext()) {
                Object personObj = iter.next();
                dom4jSession.save(Person.class.getName(), personObj);
            }

            session.flush();
            tx.commit();
            session.close();
        } catch (HibernateException e) {
            e.printStackTrace();
        } catch (DocumentException e) {
            e.printStackTrace();
        }
    }

    private Configuration setupDb(final File baseDir) throws HibernateException {
        Configuration cfg = new Configuration();
        cfg.addFile(new File(baseDir, "name/seller/rich/hobby/Person.hbm.xml"));
        cfg.addFile(new File(baseDir, "name/seller/rich/hobby/Hobby.hbm.xml"));

        SchemaExport export = new SchemaExport(cfg);

        export.setOutputFile("hobbyDB.txt");
        export.execute(false, true, false, false);
        return cfg;
    }
}

This is the resulting content in the PEOPLE table.

PEOPLE_ID           |NAME        |HOBBIES              
-------------------------------------------------------
1                   |Dave        |drinking, walking    
2                   |Geoff       |football, ballet     
3                   |Anne        |walking, karate      
4                   |Frank       |karate, cross-stitch

... and these are the empty tables HOBBIES and PEOPLE_HOBBIES:

HOBBY:

HOBBY
----------------------

0 rows selected

PEOPLE_HOBBIES:

PEOPLE_ID           |HOBBY
---------------------------------------

0 rows selected
+3
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4 answers

xml . , , .

:

<People>
  <Person Id="1" Name="Dave" Hobbies="drinking, walking"/>
  <Person Id="2" Name="Geoff" Hobbies="football, ballet"/>
  <Person Id="3" Name="Anne" Hobbies="walking, karate"/>
  <Person Id="4" Name="Frank" Hobbies="karate, cross-stitch"/>
</People>

:

<People>
  <Person Id="1" Name="Dave">
    <Hobbies>
      <Hobby>drinking</Hobby>
      <Hobby>walking</Hobby>
    </Hobbies>
  </Person>

  ...
</People>

XSLT script - . XSLT - , , HTML.

.

+2

Hibernate hobbies, Person. hobbiesSet , , , . , .

, . , . XML , , Hibernate , .

+1

, . , list , , , EntityMode.DOM4J. org.hibernate.type.CollectionType.replaceElements():

//TODO: EntityMode.DOM4J!

ElementHandler SAXReader , :

SAXReader saxReader = new SAXReader();
saxReader.addHandler("/People/Person", new ElementHandler() {

    public void onEnd(final ElementPath elementPath) {
        Element element = elementPath.getCurrent();
        Attribute hobbyAttribute = element.attribute("Hobbies");

        if (hobbyAttribute != null) {
            String hobbies = hobbyAttribute.getValue();
            Element hobbiesList = new DefaultElement("Hobbies");
            element.add(hobbiesList);
            String[] hobbiesArray = hobbies.split(",");

            for (String hobby : hobbiesArray) {
                if (hobby.trim().length() > 0) {
                    Element hobbyElement = new DefaultElement("Hobby");
                    hobbiesList.add(hobbyElement);
                    Element idElement = new DefaultElement("id");
                    hobbyElement.add(idElement);
                    idElement.setText(hobby.trim());
                }
            }
        }
    }

    public void onStart(final ElementPath elementPath) {
        //no-op;
    }
});

:

while (iter.hasNext()) {
    Object peopleObj = iter.next();
    dom4jSession.merge(Person.class.getName(), peopleObj);
}

, ( ).

.hbm.xml:

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="name.seller.rich.hobby">  
  <class name="Hobby" node="Hobby" table="HOBBIES">
    <!--id name="id" column="HOBBY_ID">
      <generator class="native"/>
    </id-->
    <id name="id" column="HOBBY_ID" type="string"/>
    <set name="people" table="PEOPLE_HOBBIES" inverse="true">
      <key column="HOBBY_ID"/>
      <many-to-many column="PEOPLE_ID" class="Person"/>
    </set>
  </class>
</hibernate-mapping>

Person.hbm.xml:

<hibernate-mapping package="name.seller.rich.hobby">  
  <class name="Person" node="Person" table="PEOPLE">
    <id name="id" node="@Id" column="PEOPLE_ID"/>
    <property name="name" node="@Name" column="NAME" type="string"/>
    <!-- property name="hobbies" node="@Hobbies" column="HOBBIES" type="string"/-->
    <set name="hobbies" node="Hobbies" table="PEOPLE_HOBBIES" cascade="save-update,persist">
    <key column="PEOPLE_ID"/>
    <many-to-many column="HOBBY_ID" class="Hobby"/>
    </set>
  </class>
</hibernate-mapping>
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We tried to use the Hibernate DOM4J and POJO entity modes in the same application some time ago. It may have already matured, but we had nothing but problems with the DOM4J entity.

I would recommend using Hibernate with your POJOs and using something like XStream or raw DOM4J to serialize XML to and from POJO.

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Source: https://habr.com/ru/post/1712416/

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