Hibernate（二）实现数据库的基本操作及相关api

配置过程省略。

数据库连接的公共类HibernateUtils.java

package test.hibernate.dao;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

public class HibernateUtils {

private static SessionFactory sessionFactory;

static {
// Configuration configuration=new Configuration();
// configuration.configure();//读取默认的文件hibernate.cfg.xml
// // configuration.configure("hibernate.cfg.xml");读取指定文件
// sessionFactory=configuration.buildSessionFactory();
sessionFactory = new Configuration()//
.configure()//
.buildSessionFactory();
}

/*
* 获得一个全局唯一的SessionFactory
*
* @return
*/

public static SessionFactory getSessionFactory() {
return sessionFactory;
}

/*
* 从全局SessionFactory中打开一个Session
*/
public static Session openSession() {
return sessionFactory.openSession();
}

public static void setSessionFactory(SessionFactory sessionFactory) {
HibernateUtils.sessionFactory = sessionFactory;
}

}

QueryResult.java

package test.hibernate.dao;

import java.util.List;

public class QueryResult {

private int count;
private List list;

public QueryResult(int count, List list) {
this.count = count;
this.list = list;
}

public int getCount() {
return count;
}

public void setCount(int count) {
this.count = count;
}

public List getList() {
return list;
}

public void setList(List list) {
this.list = list;
}

}

业务实现类UserDao.java

package test.hibernate.dao;

import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Restrictions;

import test.hibernate.domain.User;

/**
* @author LinDL
*
*/
public class UserDao {

public void save(User user) {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
session.save(user);
transaction.commit();
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {

}
session.close();
}

public void update(User user) {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
session.update(user);
transaction.commit();
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {

}
session.close();
}

public void delete(int id) {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
User user = (User) session.get(User.class, id);// 要先获取到实体对象
session.delete(user);// 删除的是实体对象
transaction.commit();
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {

}
session.close();
}

/**
* @param id
* @return
*/
public User getById(int id) {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
User user = (User) session.get(User.class, id);
transaction.commit();
return user;
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {
session.close();
}
}

/**
* @return
*/
public List<User> findAll() {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
// 使用HQL查询
// List<User> all = session.createQuery("from User").list();
// 使用面向对象的方式查询
Criteria criteria = session.createCriteria(User.class);
// criteria.add(Restrictions.eq("id", 5));// 添加限制条件，查询id等于5的记录
// criteria.add(Restrictions.ge("id", 6));//
// 查询id大于等于6的记录，lt表小于,le表小于等于
// criteria.addOrder(Order.asc("id"));// 添加排序条件

List<User> all = criteria.list();

transaction.commit();
return all;
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {
session.close();
}
}

/**
* @param firstResult
* @param maxResult
* @return
*/
@SuppressWarnings("unchecked")
public QueryResult findAll(int firstResult, int maxResult) {
Session session = HibernateUtils.openSession();
Transaction transaction = null;
try {
transaction = session.beginTransaction();
// 使用HQL查询
// Query query = (Query) session.createQuery("from User");
// query.setFirstResult(firstResult);
// query.setMaxResults(maxResult);
// List<User> all = query.list();
List<User> all = session.createQuery("from User")
.setFirstResult(firstResult)//
.setMaxResults(maxResult)//
.list();

// 查询总记录数
Long count = (Long) session
.createQuery("select count(*) from User").uniqueResult();
transaction.commit();

return new QueryResult(count.intValue(), all);
} catch (RuntimeException e) {
// TODO: handle exception
transaction.rollback();
throw e;
} finally {
session.close();
}
}
}

测试类

package test.hibernate.dao;

import static org.junit.Assert.*;

import java.util.List;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import test.hibernate.domain.User;

public class UserDaoTest {

UserDao userDao = new UserDao();

@Test
public void testSave() {
User user = new User();
// user.setName("张三");
// userDao.save(user);
for (int i = 1; i < 30; i++) {
user.setId(i);
user.setName("test" + i);
userDao.save(user);
}
}

@Test
public void testUpdate() {
User user = userDao.getById(2);
user.setName("历史");
userDao.update(user);
}

@Test
public void testDelete() {
userDao.delete(2);
}

@Test
public void testGetById() {
User user = userDao.getById(1);
System.out.println(user);
}

@Test
public void testFindAll() {
List<User> list = userDao.findAll();
for (User user : list) {
System.out.println(user);
}
}

@Test
public void testFindAllIntInt() {
// QueryResult queryResult = userDao.findAll(0, 10);
// QueryResult queryResult=userDao.findAll(10, 10);
QueryResult queryResult = userDao.findAll(20, 10);
System.out.println("总记录数" + queryResult.getCount());
for (Object user : queryResult.getList()) {
System.out.println(user);
}
}

}

Configuration 配置
configure()

configure(String resource)
addResource(String resource)导入一个指定位置的映射文件
addClass(Class clazz)导入与指定类同一个包中的以类名为前缀，后缀为.hbm.xml的映射文件
buildSessionFactory()

SessionFactory Session工厂
openSession()
getCurrentSession()
close()

Session 很重要的一个对象
操作对象的方法
save(Object)
update(Object)
delete(Object)
查询的方法
createQuery(String)--> Query
createCriteria(Class)
管理事务的方法
beginTransaction() --> Transaction
getTransaction()   --> Transaction获取当前Session中关联的事务对象
其他的方法
...

Transaction 事务
commit()
rollback()

Query 查询
list()
查询一个结果集合。
uniqueResult()查询一个唯一的结果，如果没有结果，则返回null，如果结果有多个，就抛异常。

...

原文出处：http://blog.csdn.net/lindonglian/article/details/46858451