HQL语句

hql分页

/**
     * 使用hql语句进行分页查询操作 Description:
     * 
     * @param hql
     *            HQL语句
     * @param startIndex
     *            索引数据的起始位置
     * @param length
     *            索引的长度
     * @return ORM对象的泛型集合
     * @throws HibernateDaoException
     *             运行时异常
     */
    @SuppressWarnings("unchecked")
    public <T> List<T> findByPage(String hql, int startIndex, int length) {
        List<T> list = new ArrayList<T>();
        final String str = hql;
        final int offset = startIndex;// 开始索引的下标
        final int size = length;
        try {
            list = this.getHibernateTemplate().executeFind(
                    new HibernateCallback<Object>() {
                        @Override
                        public Object doInHibernate(Session session)
                                throws HibernateException, SQLException {
                            List<T> list = session.createQuery(str)
                                    .setFirstResult(offset).setMaxResults(size)
                                    .list();
                            return list;
                        }
                    });
        } catch (Exception e) {
            list = new ArrayList<T>();
            logger.error(e.toString());
        }
        return list;
    }

    /**
     * 使用hql语句进行分页查询操作 Description:
     *
     * @param hql
     *            Hql语句
     * @param values
     *            如果hql有多个参数需要传入，values就是传入的参数数组
     * @param startIndex
     *            开始索引的位置
     * @param length
     *            索引的长度
     * @return ORM对象的泛型集合
     * @throws HibernateDaoException

     *             运行时异常
     */
    @SuppressWarnings("unchecked")
    public <T> List<T> findByPage(String hql, Object[] values, int startIndex,int length) {
        List<T> list = new ArrayList<T>();
        final String str = hql;
        final Object[] val = values;
        final int offset = startIndex;
        final int pageSize = length;
        try {
            list = this.getHibernateTemplate().executeFind(
                    new HibernateCallback<Object>() {
                        public Object doInHibernate(Session session)
                                throws HibernateException, SQLException {
                            Query query = session.createQuery(str);
                            for (int i = 0; i < val.length; i++) {
                                query.setParameter(i, val[i]);
                            }
                            List<T> list = query.setFirstResult(offset)
                                    .setMaxResults(pageSize).list();
                            return list;
                        }

                    });
        } catch (Exception e) {
            list = new ArrayList<T>();
            logger.error(e.toString());
        }
        return list;
    }

HQL常用查询：

package com.b510.example;
 
import java.util.Iterator;
import java.util.List;
import java.util.Map;
 
import org.hibernate.Criteria;
import org.hibernate.FetchMode;
import org.hibernate.Query;
import org.hibernate.Session;
 
/**
 *  
 */
public class HibernateTest {
 
 /**
  * @param args
  */
 public static void main(String[] args) {
  HibernateTest test = new HibernateTest();
  test.where();
  test.function();
  test.update();
  test.jiaoChaCheck();
  test.innerJoin();
  test.QBC();
  test.leftOuterJoin();
  test.rightOuterJoin();
 }
 

 public void where() {
  // 使用where查询
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  Query query = session
    .createQuery("from User where id not between 200 and 2000");
  List<User> list = query.list();
 
  for (User user : list) {
   System.out.println(user.getId() + user.getUsername());
  }
  // 投影查询 中使用where子句
  query = session.createQuery("select username from User where id=2");
  List<String> listname = query.list();
 
  for (String name : listname) {
   System.out.println(name);
  }
  // in查询
  query = session
    .createQuery("from User where username in ('Hongten','Hanyuan','dfgd')");
  List<User> listin = query.list();
 
  for (User user : listin) {
   System.out.println(user.getId() + user.getUsername());
  }
  // like查询
  query = session.createQuery("from User where username not like 'Hon%'");
  List<User> listlike = query.list();
 
  for (User user : listlike) {
   System.out.println(user.getId() + user.getUsername());
  }
  // null查询
  query = session.createQuery("from User where password is null");
  List<User> listnull = query.list();
 
  for (User user : listnull) {
   System.out.println(user.getId() + user.getUsername());
  }
  // and查询
  query = session
    .createQuery("from User where password is not null and id<5");
  List<User> listand = query.list();
 
  for (User user : listand) {
   System.out.println(user.getId() + user.getUsername()
     + user.getPassword());
  }
  // order by
  query = session.createQuery("from User order by username,id desc");
  List<User> listorderby = query.list();
 
  for (User user : listorderby) {
   System.out.println(user.getId() + user.getUsername());
  }
  // 使用"?"号 作为参数占位符，一条HQL语句中可以使用多个？
  // query.setInteger(0,2)
  // query.setString(0,"Hongten")
  query = session
    .createQuery("select username from User where username=?");
  query.setString(0, "Hongten");
  List<String> listwenhao = query.list();
  for (String name : listwenhao) {
   System.out.println(name);
  }
 
  session.getTransaction().commit();
 
 }
 
 public void function() {// 把大写字母转化为小写字母
  // 作用可以用在：比如在一个用户注册的程序中，大小写不容易区分，但是全部转化为小写后就可以很容易进行比较
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  // 输出原始的数据
  Query query = session.createQuery("select username from User");
  List<String> list = query.list();
 
  for (String name : list) {
   System.out.println(name);
  }
  System.out.println("-------------------------------------------");
  // 输出的数据全部转化为小写
  query = session.createQuery("select lower(username) from User");
  List<String> listChange = query.list();
 
  for (String name : listChange) {
   System.out.println(name);
  }
  session.getTransaction().commit();
 }
 
 public void update() {
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  Query query = session
    .createQuery("update User set username='洪伟1231' where id=?");
  query.setInteger(0, 3);
  int rowCount = query.executeUpdate();
  System.out.println(rowCount);
  session.getTransaction().commit();
 }
 
 public void operateProfile() {// 对profile这个类执行HQL语句操作
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  // 执行查询操作
  Query query = session.createQuery("from Profile");
  List<Profile> list = query.list();
  for (Profile profile : list) {
   System.out.println(profile.getId() + profile.getEmail()
     + profile.getAddress() + profile.getMobile()
     + profile.getPostcode());
  }
  // 执行删除操作
  query = session.createQuery("delete from Profile where id=?");
  query.setInteger(0, 3);
  int rowCount = query.executeUpdate();
  System.out.println(rowCount);
  session.getTransaction().commit();
 }
 
 public void jiaoChaCheck() {//交叉查询
  //这种方法查询出来的结果是笛卡尔积，对于我们开发中没有多大用处
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  Query query=session.createQuery("from User,Profile");
  
  List<Object[]> list=query.list();
  
  for(Object[] values:list){
   User user=(User)values[0];
   System.out.print("ID :"+user.getId()+",UserName:"+user.getUsername()+",Password:"+user.getPassword());
   Profile profile=(Profile)values[1];
   System.out.println(profile.getEmail()+profile.getMobile()+profile.getAddress()+profile.getPostcode());
  }
  
  session.getTransaction().commit();
 }
 
 public void innerJoin(){//内连接查询
  /**
   * 下面三种hql语句都是可以得到相同的结果
   * String hql="select p from Profile as p inner join p.user";
   * 在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
   * String hql="select p from Profile as p inner join fetch p.user";
   * 
   * String hql="select p from Profile p,User u where p.user=u";
   * String hql="select p from Profile p,User u where p.user.id=u.id";
   *  
   */  
  Session session = HibernateSessionFactoryUtil.getSessionFactory()
    .openSession();
  session.beginTransaction();
  String hql="select p from Profile as p inner join fetch p.user";
  //String hql="select p from Profile p,User u where p.user=u";
  //String hql="select p from Profile p,User u where p.user.id=u.id";
  Query query=session.createQuery(hql);
  List<Profile> list=query.list();
  for(Profile p:list){
   System.out.println("ID:"+p.getUser().getId()+"   Username: "+p.getUser().getUsername()+"   Email: "+p.getEmail()+",   Address: "+p.getAddress());
  }
  session.getTransaction().commit();
  }
 
 public void QBC(){//QBC中实现内连接查询
  Session session=HibernateSessionFactoryUtil.getSessionFactory().openSession();
  session.beginTransaction();
  Criteria criteria=session.createCriteria(Profile.class).createCriteria("user");
  List<Profile> list=criteria.list();
  
  for(Profile p:list){
   System.out.println("ID:"+p.getUser().getId()+"   Username: "+p.getUser().getUsername()+"   Email: "+p.getEmail()+",   Address: "+p.getAddress());
  }
  //QBC中实现外连接
  System.out.println("##################################################");
  criteria=session.createCriteria(Profile.class).setFetchMode("user", FetchMode.JOIN);
  List<Profile> listp=criteria.list();
  
  for(Profile p:list){
   System.out.println("ID:"+p.getUser().getId()+"   Username: "+p.getUser().getUsername()+"   Email: "+p.getEmail()+",   Address: "+p.getAddress());    
  }  
  session.getTransaction().commit();
 }
 
 public void leftOuterJoin(){//左外连接
  /**
   * String hql="select p from Profile p left outer join p.user order by p.user.id";
   * 在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
   * String hql="select p from Profile p left outer join fetch p.user order by p.user.id";
   *
   * String hqlu="select u from User u left outer join u.profiles";
   *  在下面的hql语句中加入"fetch"后，此hql语句变为了"迫切HQL"语句，这样的查询效率要比上面的hql语句要高
   * String hqlu="select u from User u left outer join fetch u.profiles";
   */
  Session session=HibernateSessionFactoryUtil.getSessionFactory().getCurrentSession();
  session.beginTransaction();
  String hql="select p from Profile p left outer join fetch p.user order by p.user.id";
  Query query=session.createQuery(hql);
  
  List<Profile> list=query.list();
  for(Profile p:list){
   System.out.println("ID:"+p.getUser().getId()+"   Username: "+p.getUser().getUsername()+"   Email: "+p.getEmail()+",   Address: "+p.getAddress());
  }
  
  System.out.println("-------------------------------------");
  String hqlu="select u from User u left outer join fetch u.profiles";
  query=session.createQuery(hqlu);
  
  List<User> listu=query.list();
  for(User u:listu){
   System.out.println(u.getId()+u.getUsername()+u.getProfiles());
  }
  session.getTransaction().commit();
   
 }
 
 public void rightOuterJoin(){//右外连接
  Session session=HibernateSessionFactoryUtil.getSessionFactory().getCurrentSession();
  session.beginTransaction();
  String hql="select u from User u right outer join u.profiles order by u.id";
  Query query=session.createQuery(hql);
  
  List<User> listu=query.list();
  for(User user:listu){
   System.out.println(user.getId()+user.getUsername()+user.getProfiles());
  }
  
  session.getTransaction().commit();
   
 }
 
}