Hibernate一对多双向映射及乐观锁使用.doc

Hibernate一对多双向映射及乐观锁使用 例子两部分： 1、一对多双向映射：模型是“班级学生”模型。两个实体分别是Tclass和Student。 2、乐观锁的是使用，版本分别使用递增整数和时间戳。两个实体分别是Foo和Bar。 Tclass实体及其映射： public class Tclass implements java.io.Serializable / Fields private Long cid; private String cname; private Set students = new HashSet(0); / Constructors / Property accessors . public String toString() return Tclass + cid= + cid + , cname= + cname + + ; Student实体及其映射 public class Student implements java.io.Serializable / Fields private Long sid; private Tclass tclass; private String sname; / Constructors / Property accessors . public String toString() return Student + sid= + sid + , sname= + sname + + ; 测试班级学生模型： public class Test /* * param args */ public static void main(String args) testSave(); / testDeleteTclass(); public static void testSave() Tclass c = new Tclass(); c.setCname(某班级); Student s1 = new Student(); Student s2 = new Student(); s1.setSname(张三); s1.setTclass(c); s2.setSname(李四); s2.setTclass(c); c.getStudents().add(s1); c.getStudents().add(s2); Session session = HibernateSessionFactory.getSession(); Transaction tx = session.beginTransaction(); session.save(c); mit(); session.close(); public static void testUpdateClass() System.out.println(-正在调用testUpdateClass()-); Session session = HibernateSessionFactory.getSession(); Tclass c = (Tclass) session.load(Tclass.class, Long.valueOf(1L); System.out.println(c); c.setCname(班级更名); session.beginTransaction().commit(); public static void testUpdateStudent() System.out.println(-正在调用testUpdateStudent()-); Session session = HibernateSessionFactory.getSession(); Tclass c = (Tclass) session.load(Tclass.class, Long.valueOf(3L); Student s = (Student) session.load(Student.class, Long.valueOf(2L); s.setSname(学生改名换姓-王八); s.setTclass(c); System.out.println(c); System.out.println(s); session.beginTransaction().commit(); System.out.println(s); System.out.println(s.getTclass(); public static void testDeleteStudent() System.out.println(-正在调用testDelete()-); Session session = HibernateSessionFactory.getSession(); Student s = (Student) session.load(Student.class, Long.valueOf(5L); System.out.println(s); System.out.println(s.getTclass(); session.delete(s); session.beginTransaction().commit(); public static void testDeleteTclass() System.out.println(-正在调用testDelete()-); Session session = HibernateSessionFactory.getSession(); Tclass c = (Tclass) session.load(Tclass.class, Long.valueOf(3L); System.out.println(c); session.delete(c); session.beginTransaction().commit(); public static void testQueryClass() System.out.println(-正在调用testQueryClass()-); Session session = HibernateSessionFactory.getSession(); Tclass c = (Tclass) session.load(Tclass.class, new Long(1); System.out.println(c); System.out.println(c.getStudents(); public static void testQueryStudent() System.out.println(-正在调用testQueryStudent()-); Session session = HibernateSessionFactory.getSession(); Student s = (Student) session.load(Student.class, new Long(1); System.out.println(s); System.out.println(s.getTclass(); 下面是乐观锁的使用： 1、基于整数的版本控制 Foo实体和映射文件 public class Foo implements java.io.Serializable / Fields private Long pid; private Integer version; private String name; / Constructors / Property accessors . public String toString() return Foo + pid= + pid + , version= + version + , name= + name + + ; 测试： public class TestFoo /* * param args */ public static void main(String args) testSave(); public static void testSave() Foo foo1 = new Foo(foo1); Session session = HibernateSessionFactory.getSession(); session.save(foo1); session.beginTransaction().commit(); session.close(); 2、基于时间戳的版本控制 public class Bar implements java.io.Serializable, Comparable / Fields private Long id; private Date timestamp; private String name; / Constructors / Property accessors . public String toString() return Bar + id= + id + , timestamp= + timestamp + , name= + name + + ; /* * 排序接口方法实现，为了能对查询结果按照id的大小进行排序 * param o 排序对象 * return 比较值 */ public int compareTo(Object o) Bar bar = (Bar) o; Long res = this.id - bar.getId(); return Value(); public class TestBar public static void main(String args) testUpdateBar(); testQueryBar(); public static void testSaveBar() Bar bar = new Bar(bar); Session session = HibernateSessionFactory.getSession(); session.save(bar); session.beginTransaction().commit(); session.close(); public static void testQueryBar() Session session = HibernateSessionFactory.getSession(); String hql = from Bar; Query query = session.createQuery(hql); List barList = query.list(); Collections.sort(barList); for (Bar bar : barList) System.out.println(bar.getId() + :t + bar.getTimestamp().getTime(); session.close(); public static void testUpdateBar() Session session = HibernateSessionFactory.getSession(); String hql = from Bar; Query query = session.createQuery(hql); List barList = query.list(); for (Bar bar : barList) bar.setName(newBar); session.beginTransaction().commit(); session.close(); public class TestStack public static void main(String args) test(); public static void test() Stack stack = new Stack(); String s1= 1; String s2=2; String s3= 3; String s4= 4; stack.push(s1); stack.push(s2); stack.push(s3); stack.push(s4); for(;!stack.isEmpty();) System.out.println(stack.pop(); /for语句先判断是否符合条件,然后确定是否执行循环 for(int i=0;i10;i-) System.out.println( +i); 下面是SessionFactory工具和hibernate配置文件： import org.hibernate.HibernateException; import org.hibernate.Session; import org.hibernate.cfg.Configuration; /* * Configures and provides access to Hibernate sessions, tied to the * current thread of execution. Follows the Thread Local Session * pattern, see link /42.html . */ public class HibernateSessionFactory /* * Location of hibernate.cfg.xml file. * Location should be on the classpath as Hibernate uses * #resourceAsStream style lookup for its configuration file. * The default classpath location of the hibernate config file is * in the default package. Use #setConfigFile() to update * the location of the configuration file for the current session. */ private static String CONFIG_FILE_LOCATION = /hibernate.cfg.xml; private static final ThreadLocal threadLocal = new ThreadLocal(); private static Configuration configuration = new Configuration(); private static org.hibernate.SessionFactory sessionFactory; private static String configFile = CONFIG_FILE_LOCATION; static try configuration.configure(configFile); sessionFactory = configuration.buildSessionFactory(); catch (Exception e) System.err .println(% Error Creating SessionFactory %); e.printStackTrace(); private HibernateSessionFactory() /* * Returns the ThreadLocal Session instance. Lazy initialize * the SessionFactory if needed. * * return Session * throws HibernateException */ public static Session getSession() throws HibernateException Session session = (Session) threadLocal.get(); if (session = null | !session.isOpen() if (sessionFactory = null) rebuildSessionFactory(); session = (sessionFactory != null) ? sessionFactory.openSession() : null; threadLocal.set(session); return session; /* * Rebuild hibernate session factory * */ public static void rebuildSessionFactory() try configuration.configure(configFile); sessionFactory = configuration.buildSessionFactory(); catch (Exception e) System.err .println(% Error Creating SessionFactory %); e.printStackTrace(); /* * Close the single hibernate session instance. * * throws HibernateException */ public static void closeSession() throws HibernateException Session session = (Session) threadLocal.get(); threadLocal.set(null); if (session != null) session.close(); /* * return session factory * */ public static org.hibernate.SessionFactory getSessionFactory() return sessionFactory; /* * return session factory * * session factory will be rebuilded in the next call */ public static void setConfigFile(String configFile) HibernateSessionFactory.configFile = configFile; sessionFactory = null; /* * return hibernate configuration * */ public static Configuration getConfiguration() return configuration; root jdbc:mysql:/localhost:3306/testdb org.hibernate.dialect.MySQLDialect com.mysql.jdbc.Driver leizhimin com.mysql.jdbc.Driver true !-true- create 数据库用的是mysql5，sql脚本我导出了一份如下： /* SQLyog Enterprise - MySQL GUI v6.5 MySQL - 5.0.45-community-nt : Database - testdb * */ /*!40101 SET NAMES utf8 */; /*!40101 SET SQL_MODE=*/; /*!40014 SET OLD_FOREIGN_KEY_CHECKS=FOREIGN_KEY_CHECKS, FOREIGN_KEY_CHECKS=0 */; /*!40101 SET OLD_SQL_MODE=SQL_MODE, SQL_MODE=NO_AUTO_VALUE_ON_ZERO */; create database if not exists testdb; USE testdb; /*Table structure for table bar */ DROP TABLE IF EXISTS bar; CREATE TABLE bar ( id bigint(20) NOT NULL auto_increment, timestamp datetime NOT NULL, name varchar(24) NOT NULL, PRIMARY KEY (id) ) ENGINE=Inno