Annotations in Spring and Hibernate

<context:annotation-config />

<context:component-scan base-package="org.springframework.samples.petclinic.web"/>

@Repository(value="") - dao class anotation

@Service(value = "") - service class anotation

@Component(value="") - bean class anotation

@SpringBean(name ="servicebeanname") - to use service in apache wicket pages

Hibernate annotations

Hibernate supports the three basic inheritance mapping strategies:

   table per class hierarchy - @Inheritance(strategy = InheritanceType.SINGLE_TABLE)

   table per subclass - @Inheritance(strategy = InheritanceType.JOINED)

   table per concrete class - @Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

In addition, Hibernate supports a fourth, slightly different kind of polymorphism:

   implicit polymorphism

It is possible to use different mapping strategies for different branches of the same inheritance hierarchy. You can then make use of implicit polymorphism to achieve polymorphism across the whole hierarchy. However, Hibernate does not support mixing <subclass>, <joined-subclass> and <union-subclass> mappings under the same root <class> element. It is possible to mix together the table per hierarchy and table per subclass strategies under the the same <class> element, by combining the <subclass> and <join> elements (see below for an example).

It is possible to define subclass, union-subclass, and joined-subclass mappings in separate mapping documents directly beneath hibernate-mapping. This allows you to extend a class hierarchy by adding a new mapping file. You must specify an extends attribute in the subclass mapping, naming a previously mapped superclass. Previously this feature made the ordering of the mapping documents important. Since Hibernate3, the ordering of mapping files is irrelevant when using the extends keyword. The ordering inside a single mapping file still needs to be defined as superclasses before subclasses.

@Entity

@Table(name = "")

@NamedQueries({

      @NamedQuery(name = "nameofthequery",

                  query = "hibernatequery"),

@NamedQuery(name = "nameofthequery",

                  query = "hibernatequery")

})

@Id

@GeneratedValue(strategy = GenerationType.IDENTITY)

@Column(name = "tablecolumnname", unique = true, nullable = false)

private Integer id;

@ManyToOne(cascade ={CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH},fetch=FetchType.EAGER)

@JoinColumn(name=" tablecolumnname", nullable=false)

@ManyToOne(cascade = CascadeType.REFRESH,fetch=FetchType.EAGER)

@JoinColumn(name=" tablecolumnname", nullable=false)

@Column(name=" tablecolumnname", nullable=false, length=20)

private String name;

@Temporal( TemporalType.DATE)

@Column(name=" tablecolumnname", nullable=false)

private Date varDate;

@ManyToOne(cascade = CascadeType.REFRESH,fetch=FetchType.EAGER)

@JoinColumn(name=" tablecolumnname")

private A a;

@OneToMany(mappedBy="A")

private List<A> list;

@ManyToOne(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH},fetch=FetchType.EAGER)

@JoinColumn(name=" tablecolumnname", nullable=false, insertable=false, updatable=false)

private A a;

@OneToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH}, mappedBy = "xxx")

//@OneToMany(mappedBy="xxx")

private List<Organization> yyy;

@ManyToMany(mappedBy="zzz")

private List<vvv> vvv;

@ManyToMany(cascade = {CascadeType.PERSIST, CascadeType.MERGE, CascadeType.REFRESH},fetch = FetchType.LAZY)

      @JoinTable(name = "tablename", joinColumns =

      { @JoinColumn(name = "tanlecolumn",

                  nullable = false,

                  updatable = false) },

                  inverseJoinColumns =

                  { @JoinColumn(name = "tablecolumn",

                              nullable = false, updatable = false) })

      private List<yyy> yyyy;

complex id

----------

@EmbeddedId

PKClass id;

@Embeddable

public static class PKClass implements Serializable {

private static final long serialVersionUID = 1L;

            @Column(name=" tablecolumnname ", unique=true, nullable=false)

            private int a1;

           

            @Column(name=" tablecolumnname", unique=true, nullable=false)

            private int a2;

            public PKClass () {

          }

           

            public int getXXX() {

                  return XXX;

            }

           

            public void setXXX(int XXX) {

                  this.XXX = XXXX;

            }

           

            public int getXXX() {

                  return XXX;

            }

           

            public void setXXX(int XXX) {

                  this.XXX = XXX;

            }

           

            public boolean equals(Object other) {

                  if (this == other) {

                        return true;

                  }

                  if (!(other instanceof PKClass)) {

                        return false;

                  }

                  PKClass castOther = (PKClass)other;

                  return

                        (this.XXXX == castOther.XXXX)

                        && (this.XXX == castOther.XXX);

          }

         

            public int hashCode() {

                  final int prime = 31;

                  int hash = 17;

                  hash = hash * prime + this.XXXX;

                  hash = hash * prime + this.XXX;

                 

                  return hash;

          }

     

      }

Query examples: