Mappage d'Hibernate OneToMany par l'Annotation

Question

Mes amis J'ai deux entités: Employé et Département associé à l'association OneToMany. C'est-à-dire qu'un employé peut travailler dans plus d'un département. J'ai créé deux employés et deux départements. Les deux employés travaillent dans les mêmes départements. Lorsque je sauvegarde ces entités, j'obtiens cette exception. J'ai donné ici le code complet de mon programme. Merci d'avance pour aider quelqu'un. Code: -

- Département Entité ---

package anno; 

import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.Id; 
import javax.persistence.Table; 

@Entity 
@Table(name="annoDept") 
public class AnnoDept { 


    @Id 
    @Column(name = "deptid") 
    private Integer anid; 
    @Column(name = "deptname") 
    private String anname; 

    public Integer getAnid() { 
     return anid; 
    } 

    public void setAnid(Integer anid) { 
     this.anid = anid; 
    } 

    public String getAnname() { 
     return anname; 
    } 

    public void setAnname(String anname) { 
     this.anname = anname; 
    } 

    public boolean equals(Object obj) 
    { 
     if(!(obj instanceof AnnoDept)) 
      return false; 
      if(((AnnoDept)obj).getAnid()==this.getAnid() && ((AnnoDept)obj).getAnname().equalsIgnoreCase(this.getAnname())) 
       return true; 
      return false; 

    } 
} 



--Employee Entity code: -- 

package anno; 

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

import javax.persistence.CascadeType; 
import javax.persistence.Column; 
import javax.persistence.Entity; 
import javax.persistence.Id; 
import javax.persistence.JoinColumn; 
import javax.persistence.OneToMany; 
import javax.persistence.Table; 

@Entity 
@Table(name="annoEmp") 
public class AnnoEmp { 
    @Id 
    private Integer empid; 

    @Column(name="EName") 
    private String empname; 
    public Integer getEmpid() { 
     return empid; 
    } 
    public void setEmpid(Integer empid) { 
     this.empid = empid; 
    } 
    public String getEmpname() { 
     return empname; 
    } 
    public void setEmpname(String empname) { 
     this.empname = empname; 
    } 
    public Set<AnnoDept> getDepts() { 
     return depts; 
    } 
    public void setDepts(Set<AnnoDept> depts) { 
     this.depts = depts; 
    } 

    @OneToMany(cascade={CascadeType.ALL}) 
    private Set<AnnoDept> depts=new HashSet<AnnoDept>(); 
} 

-- hibernate.cfg.xml file code: -- 

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE hibernate-configuration PUBLIC 
      "-//Hibernate/Hibernate Configuration DTD 3.0//EN" 
      "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"> 

<hibernate-configuration> 
<session-factory> 
    <property name="connection.driver_class">com.mysql.jdbc.Driver</property> 
    <property name="connection.url">jdbc:mysql://localhost:3306/test</property> 
    <property name="connection.username">root</property> 
    <property name="connection.password">root</property> 
    <property name="hibernate.hbm2ddl.auto">update</property> 
    <property name="hibernate.show_sql">true</property> 
    <property name="hibernate.format_query">true</property> 
    <mapping class="anno.AnnoEmp"/> 
    <mapping class="anno.AnnoDept"/> 

</session-factory> 
</hibernate-configuration> 





--Test code:-- 

package anno; 

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

import org.hibernate.Session; 
import org.hibernate.SessionFactory; 
import org.hibernate.Transaction; 
import org.hibernate.cfg.AnnotationConfiguration; 

public class AnnoTest { 

    /** 
    * @param args 
    */ 
    public static void main(String[] args) { 
     // TODO Auto-generated method stub 

    SessionFactory sf=new AnnotationConfiguration().configure("mypack/hibernate.cfg.xml").buildSessionFactory(); 
    Session hs=sf.openSession(); 
    Transaction tx=hs.beginTransaction(); 

    AnnoDept dept=new AnnoDept(); 
    dept.setAnid(100);dept.setAnname("HR"); 
    AnnoDept dept3=new AnnoDept(); 
    dept3.setAnid(300);dept3.setAnname("Admin"); 
    Set<AnnoDept> deptset1=new HashSet<AnnoDept>(); 

    AnnoEmp e1=new AnnoEmp(); 
    e1.setEmpid(10);e1.setEmpname("Pinku"); 
    deptset1.add(dept);deptset1.add(dept3); 
    e1.setDepts(deptset1);hs.save(e1); 
    AnnoEmp e2=new AnnoEmp(); 
    e2.setEmpid(20);e2.setEmpname("Vijay"); 

    e2.setDepts(deptset1); 
    hs.save(e2); 

    tx.commit(); 
    hs.close(); 
    sf.close(); 
    } 

} 

-- Exception --- 

log4j:WARN No appenders could be found for logger (org.hibernate.cfg.annotations.Version). 
log4j:WARN Please initialize the log4j system properly. 
Hibernate: select annodept_.deptid, annodept_.deptname as deptname1_ from annoDept annodept_ where annodept_.deptid=? 
Hibernate: select annodept_.deptid, annodept_.deptname as deptname1_ from annoDept annodept_ where annodept_.deptid=? 
Hibernate: insert into annoEmp (EName, empid) values (?, ?) 
Hibernate: insert into annoDept (deptname, deptid) values (?, ?) 
Hibernate: insert into annoDept (deptname, deptid) values (?, ?) 
Hibernate: insert into annoEmp (EName, empid) values (?, ?) 
Hibernate: insert into annoEmp_annoDept (annoEmp_empid, depts_deptid) values (?, ?) 
Hibernate: insert into annoEmp_annoDept (annoEmp_empid, depts_deptid) values (?, ?) 
Hibernate: insert into annoEmp_annoDept (annoEmp_empid, depts_deptid) values (?, ?) 
Hibernate: insert into annoEmp_annoDept (annoEmp_empid, depts_deptid) values (?, ?) 
Exception in thread "main" org.hibernate.exception.ConstraintViolationException: Could not execute JDBC batch update 
    at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:71) 
    at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43) 
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:253) 
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:237) 
    at org.hibernate.engine.ActionQueue.executeActions(ActionQueue.java:145) 
    at org.hibernate.event.def.AbstractFlushingEventListener.performExecutions(AbstractFlushingEventListener.java:298) 
    at org.hibernate.event.def.DefaultFlushEventListener.onFlush(DefaultFlushEventListener.java:27) 
    at org.hibernate.impl.SessionImpl.flush(SessionImpl.java:1000) 
    at org.hibernate.impl.SessionImpl.managedFlush(SessionImpl.java:338) 
    at org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:106) 
    at anno.AnnoTest.main(AnnoTest.java:39) 
Caused by: java.sql.BatchUpdateException: Duplicate entry '100' for key 2 
    at com.mysql.jdbc.ServerPreparedStatement.executeBatch(ServerPreparedStatement.java:665) 
    at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(BatchingBatcher.java:48) 
    at org.hibernate.jdbc.AbstractBatcher.executeBatch(AbstractBatcher.java:246) 
    ... 8 more 



Thanks 
Dal Singar yadav 

Answer 1

Vous ne devriez pas réutiliser votre "deptset1" ils sont les mêmes, mais par exemple chaque relation est détenue par des instances de AnnoEmp séparées. Vous devez donc avoir deux instances Set différentes pour chaque AnnoEmp. Mais vous l'avez déjà dans les initiales de classe d'entité. Alors pourquoi ne pas simplement réutiliser cette instance pour chacun. Voir ci-dessous:

AnnoDept dept=new AnnoDept(); 
dept.setAnid(100);dept.setAnname("HR"); 
hs.save(dept);     // ADDED LINE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG) 

AnnoDept dept3=new AnnoDept(); 
dept3.setAnid(300);dept3.setAnname("Admin"); 
hs.save(dept3);     // ADDED LINE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG) 
Set<AnnoDept> deptset1;     // REMOVED =new HashSet<AnnoDept>(); 

AnnoEmp e1=new AnnoEmp(); 
e1.setEmpid(10);e1.setEmpname("Pinku"); 
hs.save(e1);     // ADDED LINE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG) 
despset1 = e1.getDepts();    // ADDED LINE 
deptset1.add(dept);deptset1.add(dept3); 
//e1.setDepts(deptset1);     // NOT NEEDED 
//hs.save(e1); 
hs.update(e1);     // CHANGED TO UPDATE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG) 

AnnoEmp e2=new AnnoEmp(); 
e2.setEmpid(20);e2.setEmpname("Vijay"); 
hs.save(e2);     // ADDED LINE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG) 
despset1 = e2.getDepts();    // ADDED LINE 
deptset1.add(dept);deptset1.add(dept3); // ADDED LINE 
//e2.setDepts(deptset1);     // NOT NEEDED 
//hs.save(e2); 
// WE ARE EXPECTING YOUR ERROR TO OCCUR HERE WHEN STORING THE NEW 
// DATA IN THE 'Set' TO DATABASE 
hs.update(e2);     // CHANGED TO UPDATE (TO HELP DEBUG) 
hs.flush();      // ADDED LINE (TO HELP DEBUG)