1、创建Hibernate的配置文件(hibernate.cfg.xml)例子:多个员工对应一个地址。
2、创建持久化类,即其实例需要保存到数据库中的类(Employee.java)
3、创建对象-关系映射文件(Employee.hbm.xml)
4、通过Hibernate API编写访问数据库的代码
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-configuration SYSTEM "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property> <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property> <!-- Assume testone is the database name --> <property name="hibernate.connection.url">jdbc:mysql://localhost/testMany2One</property> <property name="hibernate.connection.username">root</property> <property name="hibernate.connection.password">root</property> <property name="hibernate.show_sql">true</property> <!-- List of XML mapping files --> <mapping resource="resource/Employee.hbm.xml" /> </session-factory> </hibernate-configuration>
package com.jiangge.hblearn; /** * @author jiangge */ public class Employee { private int id; private String firstName; private String lastName; private int salary; private Address address; public Employee() { } public Employee(String firstName, String lastName, int salary, Address address) { this.firstName = firstName; this.lastName = lastName; this.salary = salary; this.address = address; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } public Address getAddress() { return address; } public void setAddress(Address address) { this.address = address; } }
package com.jiangge.hblearn; /** * @author shijiangge * @version 2014-7-4 上午11:05:39 * */ public class Address { private int id; private String street; private String city; private String state; private String zipcode; public Address() { } public Address(String street, String city, String state, String zipcode) { this.street = street; this.city = city; this.state = state; this.zipcode = zipcode; } public int getId() { return id; } public void setId(int id) { this.id = id; } public String getStreet() { return street; } public void setStreet(String street) { this.street = street; } 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 getZipcode() { return zipcode; } public void setZipcode(String zipcode) { this.zipcode = zipcode; } }
create table EMPLOYEE ( id INT NOT NULL auto_increment, first_name VARCHAR(20) default NULL, last_name VARCHAR(20) default NULL, salary INT default NULL, address INT NOT NULL, PRIMARY KEY (id) );
create table ADDRESS ( id INT NOT NULL auto_increment, street_name VARCHAR(40) default NULL, city_name VARCHAR(40) default NULL, state_name VARCHAR(40) default NULL, zipcode VARCHAR(10) default NULL, PRIMARY KEY (id) );
<?xml version="1.0" encoding="utf-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <!-- Hibernate Many-to-One 关联关系: 很多员工可以对应一个地址。 初级的程序员手写 Employee.hbm.xml 映射文件,而高级程序员使用XDoclet, Middlegen and AndroMDA这些技术,自动生成映射文件。 meta 标签是可选的,用来描述类。 Hibernate的主键生成策略: 【identity】采用数据库提供的主键生成机制。如DB2、SQL Server、MySQL 中的主键生成机制。 【native】由 Hibernate 根据使用的数据库自行判断采用 identity、hilo、sequence 其中一种作为主键生成方式。 --> <hibernate-mapping> <class name="com.jiangge.hblearn.Employee" table="EMPLOYEE"> <meta attribute="class-description"> This class contains the employee detail. </meta> <id name="id" type="int" column="id"> <generator class="native" /> </id> <property name="firstName" column="first_name" type="string" /> <property name="lastName" column="last_name" type="string" /> <property name="salary" column="salary" type="int" /> <many-to-one name="address" column="address" class="com.jiangge.hblearn.Address" not-null="true" /> </class> <class name="com.jiangge.hblearn.Address" table="ADDRESS"> <meta attribute="class-description"> This class contains the address detail. </meta> <id name="id" type="int" column="id"> <generator class="native" /> </id> <property name="street" column="street_name" type="string" /> <property name="city" column="city_name" type="string" /> <property name="state" column="state_name" type="string" /> <property name="zipcode" column="zipcode" type="string" /> </class> </hibernate-mapping>
package test; import java.util.*; import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.Transaction; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import com.jiangge.hblearn.Address; import com.jiangge.hblearn.Employee; /** * 测试类:CRUD操作 * @author jiangge * */ public class ManageEmployee { private static SessionFactory factory; public static void main(String[] args) { try { factory = new Configuration().configure().buildSessionFactory(); } catch (Throwable ex) { System.err.println("Failed to create sessionFactory object." + ex); throw new ExceptionInInitializerError(ex); } ManageEmployee ME = new ManageEmployee(); /* Let us have one address object */ Address address = ME.addAddress("Kondapur", "Hyderabad", "AP", "532"); /* Add employee records in the database */ Integer empID1 = ME.addEmployee("Manoj", "Kumar", 4000, address); //("Manoj", "Kumar", 4000, address); /* Add another employee record in the database */ Integer empID2 = ME.addEmployee("Dilip", "Kumar", 3000, address);//("Dilip", "Kumar", 3000, address); /* List down all the employees */ ME.listEmployees(); /* Update employee's salary records */ ME.updateEmployee(empID1, 5000); /* Delete an employee from the database */ ME.deleteEmployee(empID2); /* List down all the employees */ ME.listEmployees(); } /* Method to add an address record in the database */ public Address addAddress(String street, String city, String state, String zipcode) { Session session = factory.openSession(); Transaction tx = null; Integer addressID = null; Address address = null; try { tx = session.beginTransaction(); address = new Address(street, city, state, zipcode); addressID = (Integer) session.save(address); tx.commit(); } catch (HibernateException e) { if (tx != null) tx.rollback(); e.printStackTrace(); } finally { session.close(); } return address; } /* Method to add an employee record in the database */ public Integer addEmployee(String fname, String lname, int salary, Address address) { Session session = factory.openSession(); Transaction tx = null; Integer employeeID = null; try { tx = session.beginTransaction(); Employee employee = new Employee(fname, lname, salary, address); employeeID = (Integer) session.save(employee); tx.commit(); } catch (HibernateException e) { if (tx != null) tx.rollback(); e.printStackTrace(); } finally { session.close(); } return employeeID; } /* Method to list all the employees detail */ public void listEmployees() { Session session = factory.openSession(); Transaction tx = null; try { tx = session.beginTransaction(); List employees = session.createQuery("FROM Employee").list(); for (Iterator iterator = employees.iterator(); iterator.hasNext();) { Employee employee = (Employee) iterator.next(); System.out.print("First Name: " + employee.getFirstName()); System.out.print(" Last Name: " + employee.getLastName()); System.out.println(" Salary: " + employee.getSalary()); Address add = employee.getAddress(); System.out.println("Address "); System.out.println("\tStreet: " + add.getStreet()); System.out.println("\tCity: " + add.getCity()); System.out.println("\tState: " + add.getState()); System.out.println("\tZipcode: " + add.getZipcode()); } tx.commit(); } catch (HibernateException e) { if (tx != null) tx.rollback(); e.printStackTrace(); } finally { session.close(); } } /* Method to update salary for an employee */ public void updateEmployee(Integer EmployeeID, int salary) { Session session = factory.openSession(); Transaction tx = null; try { tx = session.beginTransaction(); Employee employee = (Employee) session.get(Employee.class, EmployeeID); employee.setSalary(salary); session.update(employee); tx.commit(); } catch (HibernateException e) { if (tx != null) tx.rollback(); e.printStackTrace(); } finally { session.close(); } } /* Method to delete an employee from the records */ public void deleteEmployee(Integer EmployeeID) { Session session = factory.openSession(); Transaction tx = null; try { tx = session.beginTransaction(); Employee employee = (Employee) session.get(Employee.class, EmployeeID); session.delete(employee); tx.commit(); } catch (HibernateException e) { if (tx != null) tx.rollback(); e.printStackTrace(); } finally { session.close(); } } }
mysql> select * from EMPLOYEE; +----+------------+-----------+--------+---------+ | id | first_name | last_name | salary | address | +----+------------+-----------+--------+---------+ | 1 | Manoj | Kumar | 5000 | 1 | +----+------------+-----------+--------+---------+ 1 row in set mysql> select * from ADDRESS; +----+-------------+-----------+------------+---------+ | id | street_name | city_name | state_name | zipcode | +----+-------------+-----------+------------+---------+ | 1 | Kondapur | Hyderabad | AP | 532 | +----+-------------+-----------+------------+---------+ 1 row in set mysql>
log4j:WARN No appenders could be found for logger (org.hibernate.cfg.Environment). log4j:WARN Please initialize the log4j system properly. Hibernate: insert into ADDRESS (street_name, city_name, state_name, zipcode) values (?, ?, ?, ?) Hibernate: insert into EMPLOYEE (first_name, last_name, salary, address) values (?, ?, ?, ?) Hibernate: insert into EMPLOYEE (first_name, last_name, salary, address) values (?, ?, ?, ?) Hibernate: select employee0_.id as id0_, employee0_.first_name as first2_0_, employee0_.last_name as last3_0_, employee0_.salary as salary0_, employee0_.address as address0_ from EMPLOYEE employee0_ First Name: Manoj Last Name: Kumar Salary: 4000 Address Hibernate: select address0_.id as id1_0_, address0_.street_name as street2_1_0_, address0_.city_name as city3_1_0_, address0_.state_name as state4_1_0_, address0_.zipcode as zipcode1_0_ from ADDRESS address0_ where address0_.id=? Street: Kondapur City: Hyderabad State: AP Zipcode: 532 First Name: Dilip Last Name: Kumar Salary: 3000 Address Street: Kondapur City: Hyderabad State: AP Zipcode: 532 Hibernate: select employee0_.id as id0_0_, employee0_.first_name as first2_0_0_, employee0_.last_name as last3_0_0_, employee0_.salary as salary0_0_, employee0_.address as address0_0_ from EMPLOYEE employee0_ where employee0_.id=? Hibernate: update EMPLOYEE set first_name=?, last_name=?, salary=?, address=? where id=? Hibernate: select employee0_.id as id0_0_, employee0_.first_name as first2_0_0_, employee0_.last_name as last3_0_0_, employee0_.salary as salary0_0_, employee0_.address as address0_0_ from EMPLOYEE employee0_ where employee0_.id=? Hibernate: delete from EMPLOYEE where id=? Hibernate: select employee0_.id as id0_, employee0_.first_name as first2_0_, employee0_.last_name as last3_0_, employee0_.salary as salary0_, employee0_.address as address0_ from EMPLOYEE employee0_ First Name: Manoj Last Name: Kumar Salary: 5000 Address Hibernate: select address0_.id as id1_0_, address0_.street_name as street2_1_0_, address0_.city_name as city3_1_0_, address0_.state_name as state4_1_0_, address0_.zipcode as zipcode1_0_ from ADDRESS address0_ where address0_.id=? Street: Kondapur City: Hyderabad State: AP Zipcode: 532
Hibernate ManyToOne Mappings 多对一关联映射,布布扣,bubuko.com
Hibernate ManyToOne Mappings 多对一关联映射
原文地址:http://blog.csdn.net/xiaowanggedege/article/details/36876199