Hibernate-tree ing and hibernate tree

Hibernate-tree ing and hibernate tree

Tree Map

Hypothesis:

The structure of a table is as follows:

Id

Parent_id

Name

 

 

 

The company's organizational structure is tree-like ing

Example:

Package com. zgy. hibernate. model;

 

Import java. util. HashSet;

Import java. util. Set;

 

Import javax. persistence. CascadeType;

Import javax. persistence. Entity;

Import javax. persistence. FetchType;

Import javax. persistence. GeneratedValue;

Import javax. persistence. Id;

Import javax. persistence. JoinColumn;

Import javax. persistence. ManyToOne;

Import javax. persistence. onetoence;

 

 

/*

* Org class, indicating the class of the Organizational Structure

*/

@ Entity

Public class Org {

Private int id; // number

Private String name; // name

Private Set <Org> children = new HashSet <Org> (); // subclass of Org

Private Org parent; // The parent class of Org

@ Id

@ GeneratedValue

Public int getId (){

Return id;

}

Public void setId (int id ){

This. id = id;

}

Public String getName (){

Return name;

}

Public void setName (String name ){

This. name = name;

}

@ Onetoager (cascade = CascadeType. ALL, mappedBy = "parent", fetch = FetchType. EAGER)

Public Set <Org> getChildren (){

Return children;

}

Public void setChildren (Set <Org> children ){

This. children = children;

}

@ ManyToOne

@ JoinColumn (name = "parent_id ")

Public Org getParent (){

Return parent;

}

Public void setParent (Org parent ){

This. parent = parent;

}

}

 

 

Test:

Package com. zgy. hibernate. model;

 

Import java. util. Date;

Import java. util. List;

 

Import org. hibernate. Query;

 

Import org. hibernate. Session;

Import org. hibernate. SessionFactory;

Import org. hibernate. cfg. AnnotationConfiguration;

Import org. hibernate. tool. hbm2ddl. SchemaExport;

Import org. junit. AfterClass;

Import org. junit. BeforeClass;

Import org. junit. Test;

 

Public class HibernateTreeTest {

Private static SessionFactory sf;

@ BeforeClass

Public static void beforeClass (){

Sf = new AnnotationConfiguration (). configure (). buildSessionFactory ();

}

@ AfterClass

Public static void afterClass (){

Sf. close ();

}

@ Test

Public void testSchemaExport (){

New SchemaExport (new AnnotationConfiguration (). configure (). create (false, true );

}

@ Test

Public void testSave (){

Org o = new Org ();

O. setName ("Head Office ");

Org o1 = new Org ();

O1.setName ("branch 1 ");

Org o2 = new Org ();

O2.setName ("branch 2 ");

Org o11 = new Org ();

O11.setName ("department 1 under branch 1 ");

Org o12 = new Org ();

O12.setName ("branch 1 Department 2 ");

O. getChildren (). add (o1 );

O. getChildren (). add (o2 );

O1.getChildren (). add (o11 );

O2.getChildren (). add (o12 );

O11.setParent (o1 );

O12.setParent (o1 );

O1.setParent (o );

O2.setParent (o );

Session session = sf. openSession ();

Session. beginTransaction ();

Session. save (o );

Session. getTransaction (). commit ();

Session. close ();

}

@ Test

Public void testLoad (){

TestSave ();

Session session = sf. getCurrentSession ();

Session. beginTransaction ();

Org o = (Org) session. load (Org. class, 1 );

Print (o, 0 );

Session. getTransaction (). commit ();

}

Private void print (Org o, int level ){

String preStr = "";

For (int I = 0; I <level; I ++ ){

PreStr + = "----";

}

System. out. println (preStr + o. getName ());

For (Org child: o. getChildren ()){

Print (child, level + 1 );

}

}

Public static void main (String [] args ){

BeforeClass ();

}

}