One-way, multiple-to-one hibernate

For example, the relationship between provinces and cities

Province. java

package www.csdn.net.blank.bean;import java.io.Serializable;public class Province  implements Serializable{/** *  */private static final long serialVersionUID = 1L;private Integer id;private String name;public Province() {super();// TODO Auto-generated constructor stub}public Province(Integer id, String name) {super();this.id = id;this.name = name;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}}

City. java

package www.csdn.net.blank.bean;import java.io.Serializable;public class City implements Serializable{    /** *  */private static final long serialVersionUID = 1L;private Integer id;        private String  name;        private Province province;public City() {super();// TODO Auto-generated constructor stub}public City(Integer id, String name) {super();this.id = id;this.name = name;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public Province getProvince() {return province;}public void setProvince(Province province) {this.province = province;}    }

Provice configuration file Provice. hbm. xml

City. hbm. xml

 
 
  
   
    
    
   
      
   
// Use Hibernate
    
     
Element to map multiple-to-one associations
    
   
Features-to-one attributes:
   
* Name: Specifies the name of the persistent class to be mapped.
   
* Column: Set the foreign key of the table corresponding to the persistence class attribute.
   
* Class: Set the attribute type of the persistence class.
   
* Not-null: whether to allow null.
     
           
         
       
  
 

Hibernate encapsulates the BaseDao interface for addition, deletion, query, and modification

Package www.csdn.net. blank. dao; import java. io. serializable; import java. util. list; @ SuppressWarnings ("rawtypes") public interface BaseDao {/*** save Object ** @ param entity */public void saveObject (Object entity ); /*** update Object ** @ param entity */public void updateObject (Object entity ); /*** Delete Object ** @ param entity */public void deleteObject (Object entity ); /*** Delete object objects by id ** @ param clazz * @ param id */public void deleteObjectById (Class clazz, Serializable id ); /*** query Object objects by id ** @ param clazz * @ param id * @ return */public Object loadObjectById (Class clazz, Serializable id ); /*** query Object objects by id ** @ param clazz * @ param id * @ return */public Object getObjectById (Class clazz, Serializable id ); /*** query all operations ** @ param clazz * @ return */public List getObjects (Class clazz );}

BaseDaoImpl

Package www.csdn.net. blank. dao. impl; import java. io. serializable; import java. util. arrayList; import java. util. list; import org. hibernate. session; import org. hibernate. transaction; import www.csdn.net. blank. dao. baseDao; import www.csdn.net. blank. util. required; @ SuppressWarnings ("rawtypes") public class BaseDaoImpl extends implements BaseDao {@ Overridepublic void saveObject (Object entity) {// obtain the session Object Session = getSessionObject (); // open the Transaction ts = session. beginTransaction (); try {// Save the session. save (entity); // submit the transaction ts. commit ();} catch (Exception e) {ts. rollback () ;}@ Overridepublic void updateObject (Object entity) {// obtain the session Object Session session = getSessionObject (); // open the Transaction ts = session. beginTransaction (); try {// Save the session. update (entity); // submit the transaction ts. commit ();} catch (Exception e) {ts. rollback () ;}@ Overridepublic void deleteObject (Object entity) {// obtain the session Object Session session = getSessionObject (); // open the Transaction ts = session. beginTransaction (); try {// Save the session. delete (entity); // submit the transaction ts. commit ();} catch (Exception e) {ts. rollback () ;}@ Overridepublic void deleteObjectById (Class clazz, Serializable id) {// obtain the session object Session session = getSessionObject (); // open the Transaction ts = session. beginTransaction (); try {// Save the session. delete (getObjectById (clazz, id); // submit the transaction ts. commit ();} catch (Exception e) {ts. rollback () ;}@ Overridepublic Object loadObjectById (Class clazz, Serializable id) {return null ;}@ Overridepublic Object getObjectById (Class clazz, Serializable id) {Object obj = null; session session = getSessionObject (); Transaction ts = session. beginTransaction (); try {obj = session. get (clazz, id); ts. commit ();} catch (Exception e) {ts. rollback ();} finally {session. close () ;}return obj ;}@ Overridepublic List getObjects (Class clazz) {List list = new ArrayList (); Session session = getSessionObject (); Transaction ts = session. beginTransaction (); try {list = session. createQuery ("from" + clazz. getName ()). list (); ts. commit ();} catch (Exception e) {ts. rollback () ;}return list ;}}

Hibernate-encapsulated tool class HiberUtil. java

Package www.csdn.net. blank. util; import org. hibernate. session; import org. hibernate. sessionFactory; import org. hibernate. boot. registry. standardServiceRegistryBuilder; import org. hibernate. cfg. configuration; import org. hibernate. service. serviceRegistry; public class HiberUtil {static Configuration cfg; static ServiceRegistry serviceRegistry; static SessionFactory sessionFactory; static {// create a Configuration object call. configure () method, default class/hibernate. cfg. xmlcfg = new Configuration (). configure (); // create a service object serviceRegistry = new StandardServiceRegistryBuilder (). applySettings (cfg. getProperties ()). build (); // create sessionFactory factory sessionFactory = cfg. buildSessionFactory (serviceRegistry);}/*** get the session object * @ return */public static Session openSession () {return sessionFactory. openSession ();}}

Hibernate. cfg. xml

 
 
  
   
   
    
Com. mysql. jdbc. Driver
   
   
   
    
Jdbc: mysql: // localhost: 3306/jd2? UseUincode = true & characterEncoding = UTF-8
   
   
   
    
Root
   
   
   
    
Root
   
   
   
    
Org. hibernate. dialect. MySQLDialect
   
   
   
    
Thread
   
   
   
    
True
   
   
   
    
False
   
   
   
    
Update
   
   
   
   
  
 

Test class

Package www.csdn.net. blank. junit; import org. junit. test; import www.csdn.net. blank. bean. city; import www.csdn.net. blank. bean. province; import www.csdn.net. blank. dao. baseDao; import www.csdn.net. blank. dao. impl. baseDaoImpl; import www.csdn.net. blank. util. hiberUtil; public class Test1 {@ Testpublic void test () {HiberUtil. openSession ();} private BaseDao baseDao = new BaseDaoImpl (); @ Testpublic void save () {Province Province = new Province (); province. setName ("HEBEI 1"); City entity = new City (); entity. setName ("Shijiazhuang"); entity. setProvince (province); baseDao. saveObject (entity) ;}@ Testpublic void update () {City entity = (City) baseDao. getObjectById (City. class, 2); if (entity! = Null) {System. out. println (entity. getName ();} else {System. out. println ("xxxx ");}}}