使用注解Hibernate一对一示例 Hibernate一对一|Hibernate

【使用注解Hibernate一对一示例】在这里, 我们将使用注解按一对一的元素执行一对一的映射。在这种情况下, 不会在主表中创建任何外键。
在此示例中, 一个雇员可以有一个地址, 而一个地址仅属于一个雇员。在这里, 我们使用双向关联。让我们看一下持久化类。
1）一对一映射的持久类
有两个持久性类Employee.java和Address.java。雇员类包含地址类引用, 反之亦然。
Employee.java

package com.srcmini; import javax.persistence.*; @Entity @Table(name="emp220") public class Employee { @Id @GeneratedValue(strategy=GenerationType.AUTO) @PrimaryKeyJoinColumn private int employeeId; private String name, email; @OneToOne(targetEntity=Address.class, cascade=CascadeType.ALL) private Address address; public int getEmployeeId() { return employeeId; } public void setEmployeeId(int employeeId) { this.employeeId = employeeId; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; }}

Address.java

package com.srcmini; import javax.persistence.*; @Entity @Table(name="address220") public class Address { @Id @GeneratedValue(strategy=GenerationType.AUTO) private int addressId; private String addressLine1, city, state, country; private int pincode; @OneToOne(targetEntity=Employee.class) private Employee employee; public int getAddressId() { return addressId; } public void setAddressId(int addressId) { this.addressId = addressId; } public String getAddressLine1() { return addressLine1; } public void setAddressLine1(String addressLine1) { this.addressLine1 = addressLine1; } public String getCity() { return city; } public void setCity(String city) { this.city = city; } public String getState() { return state; } public void setState(String state) { this.state = state; } public String getCountry() { return country; } public void setCountry(String country) { this.country = country; } public int getPincode() { return pincode; } public void setPincode(int pincode) { this.pincode = pincode; } public Employee getEmployee() { return employee; } public void setEmployee(Employee employee) { this.employee = employee; } }

2）在pom.xml文件中添加项目信息和配置。
打开pom.xml文件, 然后单击源。现在, 在< dependencies> … . < / dependencies> 标记之间添加以下依赖关系。这些依赖关系用于在Maven项目中添加jar文件。

< dependency> < groupId> org.hibernate< /groupId> < artifactId> hibernate-core< /artifactId> < version> 5.3.1.Final< /version> < /dependency>

< dependency> < groupId> com.oracle< /groupId> < artifactId> ojdbc14< /artifactId> < version> 10.2.0.4.0< /version> < /dependency>

3）配置文件
该文件包含有关数据库和映射文件的信息。
hibernate.cfg.xml

< ?xml version='1.0' encoding='UTF-8'?> < !DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 5.3//EN" "http://hibernate.sourceforge.net/hibernate-configuration-5.3.dtd"> < hibernate-configuration> < session-factory> < property name="hbm2ddl.auto"> update< /property> < property name="dialect"> org.hibernate.dialect.Oracle9Dialect< /property> < property name="connection.url"> jdbc:oracle:thin:@localhost:1521:xe< /property> < property name="connection.username"> system< /property> < property name="connection.password"> jtp< /property> < property name="connection.driver_class"> oracle.jdbc.driver.OracleDriver< /property> < mapping class="com.srcmini.Address"/> < mapping class="com.srcmini.Employee"/> < /session-factory> < /hibernate-configuration>

4）用于存储和获取数据的用户类
Store.java

package com.srcmini; import org.hibernate.*; import org.hibernate.boot.Metadata; import org.hibernate.boot.MetadataSources; import org.hibernate.boot.registry.StandardServiceRegistry; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; public class Store { public static void main(String[] args) { StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build(); Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build(); SessionFactory factory=meta.getSessionFactoryBuilder().build(); Session session=factory.openSession(); Transaction t=session.beginTransaction(); Employee e1=new Employee(); e1.setName("Ravi Malik"); e1.setEmail("ravi@gmail.com"); Address address1=new Address(); address1.setAddressLine1("G-21, Lohia nagar"); address1.setCity("Ghaziabad"); address1.setState("UP"); address1.setCountry("India"); address1.setPincode(201301); e1.setAddress(address1); address1.setEmployee(e1); session.persist(e1); t.commit(); session.close(); System.out.println("success"); } }

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Fetch.java

package com.srcmini; import java.util.Iterator; import java.util.List; import javax.persistence.TypedQuery; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.boot.Metadata; import org.hibernate.boot.MetadataSources; import org.hibernate.boot.registry.StandardServiceRegistry; import org.hibernate.boot.registry.StandardServiceRegistryBuilder; public class Fetch { public static void main(String[] args) { StandardServiceRegistry ssr=new StandardServiceRegistryBuilder().configure("hibernate.cfg.xml").build(); Metadata meta=new MetadataSources(ssr).getMetadataBuilder().build(); SessionFactory factory=meta.getSessionFactoryBuilder().build(); Session session=factory.openSession(); TypedQuery query=session.createQuery("from Employee"); List< Employee> list=query.getResultList(); Iterator< Employee> itr=list.iterator(); while(itr.hasNext()){ Employee emp=itr.next(); System.out.println(emp.getEmployeeId()+" "+emp.getName()+" "+emp.getEmail()); Address address=emp.getAddress(); System.out.println(address.getAddressLine1()+" "+address.getCity()+" "+ address.getState()+" "+address.getCountry()+" "+address.getPincode()); }session.close(); System.out.println("success"); } }

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