@Entity(name = "Employee")
@Table(name = "Employee")
public class Employee extends PersistenceEntityBase {
}
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
public Long getId() {
return id;
}
For composite entity id, use @IdClass or @EmbeddedId.
The ORM mappings for entity properties use JPA annotations on getter methods, not member variables. For example,
@Column(nullable=false, length=30)
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public class Employee extends PersistenceEntityBase {
@OneToOne(cascade={CascadeType.ALL})
@JoinColumn(name="employeeDetailId")
public EmployeeDetail getEmployeeDetail() {
}
}
public class Employee extends PersistenceEntityBase {
@ManyToOne
@JoinColumn(nullable=false, name="departmentId")
public Department getDepartment() {
return department;
}
public void setDepartment(Department department) {
this.department = department;
}
}
@Entity(name = "ExpenseClaim")
@Table(name = "ExpenseClaim")
@ParentType({ExpenseClaimItem.class})
public class ExpenseClaim extends PersistenceEntityBase {
private List<ExpenseClaimItem> expenseClaimItems;
@OneToMany(cascade={CascadeType.ALL}, orphanRemoval=true, fetch=FetchType.LAZY,
mappedBy="expenseClaim", targetEntity=ExpenseClaimItem.class)
@OrderBy(ExpenseClaimItem.PROPERTY_DATE + " DESC")
public List<ExpenseClaimItem> getExpenseClaimItems() {
return expenseClaimItems;
}
public void setExpenseClaimItems(List<ExpenseClaimItem> expenseClaimItems) {
this.expenseClaimItems = expenseClaimItems;
}
}
@Entity(name = "ExpenseClaimItem")
@Table(name = "ExpenseClaimItem")
public class ExpenseClaimItem extends PersistenceEntityBase implements ChildEntity {
private ExpenseClaim expenseClaim;
@ParentEntity
@ManyToOne
@JoinColumn(name = "expenseClaimId", nullable = false)
public ExpenseClaim getExpenseClaim() {
return expenseClaim;
}
public void setExpenseClaim(ExpenseClaim expenseClaim) {
this.expenseClaim = expenseClaim;
}
}
@OrderBy(ExpenseClaimItem.PROPERTY_DATE + " DESC")Tells JPA that the list of ExpenseClaimItems are ordered by "date" descending.
For Parent/Child relationship, parent entity type is annotated with @ParentType. Child entity type implements ChildEntity, and its parent property getter method is annotated with @ParentEntity.
public class User extends PersistenceEntityBase {
private Set<Role> roles;
@ManyToMany(fetch = FetchType.LAZY, targetEntity = Role.class)
@JoinTable(name = "User_Role",
joinColumns = {@JoinColumn(name = "userId")},
inverseJoinColumns = {@JoinColumn(name = "roleId")})
public Set<Role> getRoles() {
return roles;
}
public void setRoles(Set<Role> roles) {
this.roles = roles;
}
}
Merchandise <----- @MappedSuperclass
|
Electronics <----- @MappedSuperclass
/ \
Computer Printer <----- @Entity
Merchandise and Electronics are mapped Superclasses, and Computer and Printer
are entities mapped to separate tables.
@MappedSuperclass
abstract public class Merchandise extends PersistenceEntityBase {
}
@MappedSuperclass
abstract public class Electronics extends Merchandise {
}
@Entity(name = "Computer")
@Table(name = "Computer")
public class Computer extends Electronics {
}
@Entity(name = "Printer")
@Table(name = "Printer")
public class Printer extends Electronics {
}
EntityType A
------------
/ \
EntityType B EntityTYpe C
------------ ------------
/ \
EntityType D EntityType E
------------ ------------
For example, use SINGLE_TABLE mapping strategy with DiscriminatorColumn
for simplicity, performance and query polymorphism.
@Entity(name = "EntityTypeA")
@Table(name = "TableName")
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
@DiscriminatorColumn(name = "type", discriminatorType = DiscriminatorType.CHAR)
@DiscriminatorValue("A")
public class EntityTypeA extends PersistenceEntityBase {
}
@Entity(name = "EntityTypeB")
@DiscriminatorValue("B")
public class EntityTypeB extends EntityTypeA {
}
@Entity(name = "EntityTypeC")
@DiscriminatorValue("C")
public class EntityTypeC extends EntityTypeA {
}
@Entity(name = "EntityTypeD")
@DiscriminatorValue("D")
public class EntityTypeD extends EntityTypeB {
}
@Entity(name = "EntityTypeE")
@DiscriminatorValue("E")
public class EntityTypeE extends EntityTypeB {
}
For JPQL query polymorphism:
select * from EntityTypeB;Entities of subclass entity types (D and E) will be included in query results.
select * from EntityTypeA e where type(e) in (EntityTypeC, EntityTypeD);Select all entities of EntityTypeC and EntityTypeD.
For other mapping strategies(joined tables, separated tables), refer to JPA docs.
java.lang.String. For example,
@Column(nullable=false, length=30)
public String getName() {
return name;
}
@javax.persistence.Lob
@Column(nullable=false, length=65536)
public String getDescription() {
return description;
}
@Column(nullable=false)
@Temporal(value=TemporalType.DATE)
public Date getHiredDate() {
return hiredDate;
}
@Column(nullable=false)
@Temporal(value=TemporalType.TIMESTAMP)
public Date getCreatedDate() {
return createdDate;
}
public LocalDate getBirthday() {
return birthday;
}
public LocalDateTime getMeetingTime() {
return meetingTime;
}
public LocalTime getBusinessHourStartTime() {
return businessHourStartTime;
}
public enum EmployeeType {
FULL_TIME,
PART_TIME
}
@Column(nullable=false)
@Enumerated(value=EnumType.ORDINAL)
public EmployeeType getType() {
return type;
}
Number type. For example,
private Integer age;
private BigDecimal salary;
@Column(nullable=false)
public Integer getAge() {
}
@Column(nullable=false)
public BigDecimal getSalary() {
}
Boolean type. For example,
private Boolean active;
@Column(nullable=false)
public Boolean getActive() {
}
java.util.Locale type. For example,
private Locale locale;
@Column(nullable=false, length=15)
public Locale getLocale() {
}
<converter class="com.cmobilecom.af.entity.persistence.LocaleConverter" auto-apply="true" />Locale is mapped to its LanguageTag except ROOT which is mapped to empty string.
DataType. For example,
@Column(length=30)
public DataType getEntityType() {
return entityType;
}
<converter class="com.cmobilecom.af.entity.persistence.DataTypeConverter" auto-apply="true" />DataType is mapped to a string with format: module.typeName.
import com.cmobilecom.af.module.system.entity.UserImpl;
private User approver;
@ManyToOne(targetEntity=UserImpl.class)
@JoinColumn(name="approverUserId")
public User getApprover() {
return approver;
}
public void setApprover(User approver) {
this.approver = approver;
}
public class FullName {
String firstName;
String lastName;
public FullName(String firstName, String lastName) {
...
}
public String toString() {
return firstName + "." + lastName;
}
}
@Converter(autoApply=true)
public class FullNameConverter implements AttributeConverter<FullName, String> {
@Override
public String convertToDatabaseColumn(FullName attribute) {
if (attribute == null)
return null;
return attribute.toString();
}
@Override
public FullName convertToEntityAttribute(String dbData) {
if (dbData == null)
return null;
int index = dbData.indexOf('.');
String firstName = dbData.substring(0, index);
String lastName = dbData.substring(index + 1);
return new FullName(firstName, lastName);
}
}
@Column(length=30)
public FullName getFullName() {
return fullName;
}
<converter class="mypackage.FullNameConverter" auto-apply="true" />