亚洲1区2区3区精华液,国产精品自拍亚洲,亚洲精品电影在线

应用Hibernate3的DetachedCriteria实现分页查询

konhon 优华 — Fri, 07 Apr 2006 02:37:00 GMT

Hibernate3提供了DetachedCriteria�Q��得我们可以在Web层构造detachedCriteria�Q�然后调用业务层Bean�Q�进行动态条件查询，�Ҏ��q�一功能�Q�我设计了通用的抽象Bean基类和分��늱�支持�Q�代码来自于Quake Wang的javaeye-core包的相应�c�，然后又做了很多修攏V�?

分页支持�c�：

package com.javaeye.common.util;

import java.util.List;

public class PaginationSupport {

        public final static int PAGESIZE = 30;

        private int pageSize = PAGESIZE;

        private List items;

        private int totalCount;

        private int[] indexes = new int[0];

        private int startIndex = 0;

        public PaginationSupport(List items, int totalCount) {
                setPageSize(PAGESIZE);
                setTotalCount(totalCount);
                setItems(items);
                setStartIndex(0);
        }

        public PaginationSupport(List items, int totalCount, int startIndex) {
                setPageSize(PAGESIZE);
                setTotalCount(totalCount);
                setItems(items);
                setStartIndex(startIndex);
        }

        public PaginationSupport(List items, int totalCount, int pageSize, int startIndex) {
                setPageSize(pageSize);
                setTotalCount(totalCount);
                setItems(items);
                setStartIndex(startIndex);
        }

        public List getItems() {
                return items;
        }

        public void setItems(List items) {
                this.items = items;
        }

        public int getPageSize() {
                return pageSize;
        }

        public void setPageSize(int pageSize) {
                this.pageSize = pageSize;
        }

        public int getTotalCount() {
                return totalCount;
        }

        public void setTotalCount(int totalCount) {
                if (totalCount > 0) {
                        this.totalCount = totalCount;
                        int count = totalCount / pageSize;
                        if (totalCount % pageSize > 0)
                                count++;
                        indexes = new int[count];
                        for (int i = 0; i < count; i++) {
                                indexes[i] = pageSize * i;
                        }
                } else {
                        this.totalCount = 0;
                }
        }

        public int[] getIndexes() {
                return indexes;
        }

        public void setIndexes(int[] indexes) {
                this.indexes = indexes;
        }

        public int getStartIndex() {
                return startIndex;
        }

        public void setStartIndex(int startIndex) {
                if (totalCount <= 0)
                        this.startIndex = 0;
                else if (startIndex >= totalCount)
                        this.startIndex = indexes[indexes.length - 1];
                else if (startIndex < 0)
                        this.startIndex = 0;
                else {
                        this.startIndex = indexes[startIndex / pageSize];
                }
        }

        public int getNextIndex() {
                int nextIndex = getStartIndex() + pageSize;
                if (nextIndex >= totalCount)
                        return getStartIndex();
                else
                        return nextIndex;
        }

        public int getPreviousIndex() {
                int previousIndex = getStartIndex() - pageSize;
                if (previousIndex < 0)
                        return 0;
                else
                        return previousIndex;
        }

}

抽象业务�c?

java代码:

/**
* Created on 2005-7-12
*/
package com.javaeye.common.business;

import java.io.Serializable;
import java.util.List;

import org.hibernate.Criteria;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.criterion.DetachedCriteria;
import org.hibernate.criterion.Projections;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.javaeye.common.util.PaginationSupport;

public abstract class AbstractManager extends HibernateDaoSupport {

        private boolean cacheQueries = false;

        private String queryCacheRegion;

        public void setCacheQueries(boolean cacheQueries) {
                this.cacheQueries = cacheQueries;
        }

        public void setQueryCacheRegion(String queryCacheRegion) {
                this.queryCacheRegion = queryCacheRegion;
        }

        public void save(final Object entity) {
                getHibernateTemplate().save(entity);
        }

        public void persist(final Object entity) {
                getHibernateTemplate().save(entity);
        }

        public void update(final Object entity) {
                getHibernateTemplate().update(entity);
        }

        public void delete(final Object entity) {
                getHibernateTemplate().delete(entity);
        }

        public Object load(final Class entity, final Serializable id) {
                return getHibernateTemplate().load(entity, id);
        }

        public Object get(final Class entity, final Serializable id) {
                return getHibernateTemplate().get(entity, id);
        }

        public List findAll(final Class entity) {
                return getHibernateTemplate().find("from " + entity.getName());
        }

        public List findByNamedQuery(final String namedQuery) {
                return getHibernateTemplate().findByNamedQuery(namedQuery);
        }

        public List findByNamedQuery(final String query, final Object parameter) {
                return getHibernateTemplate().findByNamedQuery(query, parameter);
        }

        public List findByNamedQuery(final String query, final Object[] parameters) {
                return getHibernateTemplate().findByNamedQuery(query, parameters);
        }

        public List find(final String query) {
                return getHibernateTemplate().find(query);
        }

        public List find(final String query, final Object parameter) {
                return getHibernateTemplate().find(query, parameter);
        }

        public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria) {
                return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE, 0);
        }

        public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria, final int startIndex) {
                return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE, startIndex);
        }

        public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria, final int pageSize,
                        final int startIndex) {
                return (PaginationSupport) getHibernateTemplate().execute(new HibernateCallback() {
                        public Object doInHibernate(Session session) throws HibernateException {
                                Criteria criteria = detachedCriteria.getExecutableCriteria(session);
                                int totalCount = ((Integer) criteria.setProjection(Projections.rowCount()).uniqueResult()).intValue();
                                criteria.setProjection(null);
                                List items = criteria.setFirstResult(startIndex).setMaxResults(pageSize).list();
                                PaginationSupport ps = new PaginationSupport(items, totalCount, pageSize, startIndex);
                                return ps;
                        }
                }, true);
        }

        public List findAllByCriteria(final DetachedCriteria detachedCriteria) {
                return (List) getHibernateTemplate().execute(new HibernateCallback() {
                        public Object doInHibernate(Session session) throws HibernateException {
                                Criteria criteria = detachedCriteria.getExecutableCriteria(session);
                                return criteria.list();
                        }
                }, true);
        }

        public int getCountByCriteria(final DetachedCriteria detachedCriteria) {
                Integer count = (Integer) getHibernateTemplate().execute(new HibernateCallback() {
                        public Object doInHibernate(Session session) throws HibernateException {
                                Criteria criteria = detachedCriteria.getExecutableCriteria(session);
                                return criteria.setProjection(Projections.rowCount()).uniqueResult();
                        }
                }, true);
                return count.intValue();
        }
}

用户在web层构造查询条件detachedCriteria�Q�和可选的startIndex�Q�调用业务bean的相应findByCriteria�Ҏ��Q�返回一个PaginationSupport的实例ps�?

ps.getItems()得到已分��好的结果集
ps.getIndexes()得到分页索引的数�l?
ps.getTotalCount()得到�ȝ��果数
ps.getStartIndex()当前分页索引
ps.getNextIndex()下一��늃��?
ps.getPreviousIndex()上一��늃��?

konhon 优华 2006-04-07 10:37 发表评论

Hibernate配置文�g模板

konhon 优华 — Thu, 06 Apr 2006 02:45:00 GMT

xml version="1.0" encoding="UTF-8" ?>

DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"
>

< hibernate-mapping >
   < class name ="Tuser" table ="T_User" >
     < id name ="id" column ="id" type ="java.lang.Integer" >
       < generator class ="native" />
     id >
     < property name ="name" column ="name" type ="java.lang.String" />



     < property name ="resume" column ="resume" type ="clob" />
   class >
hibernate-mapping >

復合主鍵

xml version="1.0" encoding="UTF-8"?>

DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"
>

<hibernate-mapping>
  <class name="TUser2" table="T_User2">
    <composite-id name="userPk" class="TUserPk">
      <key-property name="firstName" column="firstname" type="java.lang.String"/>
      <key-property name="lastName" column="lastname" type="java.lang.String"/>
    composite-id>
    <property name="age" column="age" type="java.lang.Integer"/>
  class>
hibernate-mapping>

DISCRIMINATOR

xml version="1.0" encoding="UTF-8"?>

DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"
>

<hibernate-mapping>
  <class name="TItem" table="T_Item">
    <id name="id" column="id">
      <generator class="native"/>
    id>
    <discriminator column="category" type="java.lang.String"/>
    <property name="manufacturer" column="manufacturer"/>
    <property name="name" column="name"/>
    <subclass name="TBook" discriminator-value="1">
      <property name="pageCount" column="pagecount"/>
    subclass>
    <subclass name="TDVD" discriminator-value="2">
      <property name="regionCode" column="regionCode"/>
    subclass>
  class>
hibernate-mapping>

konhon 优华 2006-04-06 10:45 发表评论

標准的Hibernate.cfg.xml文�g SQL Server

konhon 优华 — Thu, 06 Apr 2006 02:42:00 GMT

DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd" >

< hibernate-configuration >
   < session-factory >
     < property name ="hibernate.connection.url" >
       jdbc:Microsoft:sqlserver://192.168.10.236:1433;databaseName=Sample
     property >
     < property name ="hibernate.connection.driver_class" >
       com.microsoft.jdbc.sqlserver.SQLServerDriver
     property >
     < property name ="hibernate.connection.username" >
       sa
     property >
     < property name ="hibernate.connection.password" >
       55
     property >
     < property name ="dialect" >
       org.hibernate.dialect.SQLServerDialect
     property >
     < property name ="hibernate.show_sql" >
       true
     property >
     < property name ="hibernate.transaction.factory_class" >
       org.hibernate.transaction.JDBCTransactionFactory
     property >
     < mapping resource ="TItem.hbm.xml" />
   session-factory >
hibernate-configuration >

konhon 优华 2006-04-06 10:42 发表评论

Hibernate 的CRUD

konhon 优华 — Wed, 05 Apr 2006 01:37:00 GMT

Save
// 新增名為"Emma"的用戶記�?br />Tuser user = new Tuser();
user.setName("Emma");
session.save(user);

Get
// 假設T_User表中存在ID = 1的記�?br />Tuser user = (Tuser)session.get(Tuser.class, new Integer(1));

Delete
// 假設T_User表中存在ID = 1的記�?br />Tuser user = (Tuser)session.get(Tuser.class, new Integer(1));
session.delete(user);

// 也可以通過HQL指定刪除條�g
Session.delete(" from Tuser where id = 1");

// 通過Query接口進於基於HQL的刪除操�?br />Stirng hql = "delete Tuser where id = 1";
Query query = session.createQuery(hql);
query.executeUpdate();

Find
// 通過Query接口進行數據查詢
String hql="from Tuser user where user.name like ?";
Query query = session.createQuery(hql);
query.setParameter(0, "Cartier");

List list = query.list();

Iterator it = list.iterator();
while(it.hasNext()){
Tuser user = (Tuser)it.next();
System.out.println(user.getName());
}

// 通過Criteria接口進行數據查詢
Criteria criteria = session.createCriteria(Tuser.class);
criteria.add(Expression.eq("name","Cariter"));

List list = criteria.list();

Iterator it = list.iterator();
while(it.hasNext()){
Tuser user = (Tuser)it.next();
System.out.println(user.getName());
}

konhon 优华 2006-04-05 09:37 发表评论

Hibernate 通過數據產生基礎代碼之數據連接配置文�g

konhon 优华 — Tue, 04 Apr 2006 07:42:00 GMT

使用MiddleGen for Hibernate工具.

配置./config/database下的mssql.xml文�g

    < property name ="database.script.file"            value ="" />
    < property name ="database.driver.file"            value ="${lib.dir}/mssqlserver.jar" />
    < property name ="database.driver"                 value ="com.microsoft.jdbc.sqlserver.SQLServerDriver" />
    < property name ="database.url"                    value ="jdbc:Microsoft:sqlserver://192.168.10.236:1433;databaseName=Sample" />
    < property name ="database.userid"                 value ="sa" />
    < property name ="database.password"               value ="kidsland%55" />
    < property name ="database.schema"                 value ="dbo" />
    < property name ="database.catalog"                value ="Sample" />

    < property name ="jboss.datasource.mapping"        value ="MS SQLSERVER" />

注意: database.schema �?database.catalog 不能為空.

konhon 优华 2006-04-04 15:42 发表评论

konhon 优华 — Fri, 12 Aug 2005 03:25:00 GMT

Query上有list()與iterator()�Ҏ��Q�兩者的差別在於list()�Ҏ��在讀取資料時�Q�並不會利用到快取，而是直接再向資料庫查詢，而iterator()則將讀取到的資料寫到快取，並於讀取時再次利用�?BR>
來看看下面的�E�式�Q?BR>

Session session = sessionFactory.openSession();

Query query = session.createQuery("from User");
List users = query.list();
users = query.list();

session.close();

這個程式片�D�|��使用兩次SQL來查詢資料��n�Q?BR>

Hibernate: select user0_.id as id, user0_.name as name0_, user0_.age as age0_ from user user0_
Hibernate: select user0_.id as id, user0_.name as name0_, user0_.age as age0_ from user user0_

如果在Session關閉之前�Q�要再將所有資料在取出�Q�可以��用iterator()�Ҏ��Q�例如：

Session session = sessionFactory.openSession();

Query query = session.createQuery("from User");
Iterator users = query.iterate();
users = query.iterate();

session.close();

這個程式片�D�|��使用一�ơSQL向資料��n查詢�Q�第二次則直接從快取中取得資料：

Hibernate: select user0_.id as col_0_0_ from user user0_

由於使用iterator()�Ҏ��時會使用到Session level快取�Q�所以在查詢大量資料時，會耗用大量的記憉��Q�必要時可以使用Session的evict()或clear()�Ҏ��來清除快取�?BR>

konhon 优华 2005-08-12 11:25 发表评论

Hibernate之SessionFactory与Session

konhon 优华 — Thu, 11 Aug 2005 01:14:00 GMT

Session是由SessionFactory所創徏�Q�SessionFactory是執行緒安全的（Thread-safe�Q�，您可以讓多個執行緒同時存取SessionFactory而不會有資料��q��的問��，然而Session則不是設�a�為埯��R�安全的�Q�所以試圖讓多個執行緒��q��一�?Session�Q�將會��生因資料��q��而發生�؜亂的問題�?

在Hibernate參考手冊中�?Quickstart with Tomcat 中，�C�範了一個HibernateUtil�Q�它使用了ThreadLocal��別來徏立一個Session��理的輔助類�Q�這是Hibernate的Session��理一個廣為應用的解決�Ҏ��Q�ThreadLocal�?Thread-Specific Storage 模式的一個運作實例�?BR>
由於Thread-Specific Stroage模式可以有效隔離埯��R�所使用的資料，所以避開Session的多埯��R�之間的資料��q��問題�Q�以下列出Hibernate參考手冊中的HibernateUtil��：

HibernateUtil.java

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

/**
* @author Administrator
*
* TODO To change the template for this generated type comment go to Window -
* Preferences - Java - Code Style - Code Templates
*/
public class HibernateUtil {
    private static Log log = LogFactory.getLog(HibernateUtil.class);

    private static final SessionFactory sessionFactory;
    static {
        try {
            sessionFactory = new Configuration().configure()
                    .buildSessionFactory();
        } catch (Throwable ex) {
            log.error("Initial SessionFactory creation failed.", ex);
            throw new ExceptionInInitializerError(ex);
        }
    }

    public static final ThreadLocal session = new ThreadLocal();

    public static Session currentSession() {
        Session s = (Session) session.get();
        if (s == null) {
            s = sessionFactory.openSession();
            session.set(s);
        }
        return s;
    }

    public static void closeSession() {
        Session s = (Session) session.get();
        if (s != null)
            s.clear();
        session.set(null);
    }
}

在同一個執行緒中，Session被暫存下來了�Q�但無須擔心資料庫連結Connection持續占用問題�Q�Hibernate會在真正需要資料��n操作時才�Q�從連接池中�Q�取得Connection�?

在程式中可以這麼使用HibernateUtil�Q?BR>

Session session = HibernateUtil.currentSession();
User user = (User) session.load(User.class, new Integer(1));
System.out.println(user.getName());
HibernateUtil.closeSession();

在Web應用�E�式中，可以藉助Filter來進行Session��理�Q�在需要的時候開啟Session�Q�並在Request�i�束之後關閉Session�Q�這個部份，�?JavaWorld 技術論�?/FONT> �?Wiki 上有��?在filter中關閉session 可以參�?/FONT>�?BR>

konhon 优华 2005-08-11 09:14 发表评论

如何学习Hibernate[轉]

konhon 优华 — Tue, 09 Aug 2005 08:14:00 GMT

http://www.javajia.com

Hibernate入门�Ҏ��Q�掌握精通我也不敢自夸。我�W�一遍看Hibernate文档的时候也觉得很吃力，但不是因为Hibernate难掌握而感到吃力，是因为Hibernate文档处处都是持久层设计的�l�验和最佛_��c��Hibernate文档准确的来��_��l�大部分内容都在讲对象的持久层设计，而不是简单的Hibernate使用�Q��用问题查Java doc��够了。所以学习Hibernate�Q�主要是在学习持久层的设计模式，如果你把Hibernate文档都看完了�Q�还整天只会提那�?nbsp;Hibernate的配�|�问题，Hibernate的类调用问题�Q�我觉得�q�样的�h�q�没有真正的入门�Q�算是白学了�?nbsp;

我对Hibernate 的那些配�|�也不是特别�U�熟�Q�每�ơ写hbm�Q�都要对照文档一点点的检查；�c�调用参��C��不太记得�Q�写代码也要Java doc随时备查。但是我在学习Hibernate的时候即集中所有精力来理解Hibernate的运行原理，集中�_�֊�来掌握持久层设计应该把握的原则和技巧，�q�些才对我是最重用的东�ѝ��毫不夸张的��_��学习完Hibernate�Q�我对JDBC的编�E�也提高了一大截�Q�更不要说对于J2EE架构的持久层的框架设计，基本上是了然于胸了，即�ɞ��来换了API�Q�不用Hibernate的，改用JDO�Q�Castor什么的�Q�这些经验一��L��用�?nbsp;

学习Hibernate主要不是在学习Hibernat怎么配置�Q�用工具怎么生成hbm文�g�Q�如果你把重�Ҏ��在这里，基本上等于白学了Hibernate。Hibernate的精华在于无与��u比的灵��y的对象持久层设计�Q�这些持久层设计�l�验不会因�ؓ你不用Hibernate而��失掉�Q�我自己学习Hibernate�Q�已�l�明显感觉到�Ҏ��久层设计能力已经长了很多�l�验��g��Q�这些经验甚至不光可以用在Java上，用在.net上也是一栗��所以Hibernate配置的学习，我只是简单看看，用的时候知道到那里��L��p��了，一堆复杂的生成工具我根本就看都不去看，�q�样��下来，掌握Hibernate的配�|�，可以用Hibernate来替代JDBC写程序，不过�׃��3天时间就��_��了。我�?天时间对你来说不��很奢侈的学习代价吧�?nbsp;

��Z��么我�q�么��学习Hibernate的对象持久层设计理念呢？那就看你的理��x��想一辈子做一个程序员呢？�q�是惛_��更高的方向发展呢�Q�从�U�做技术的角度来说�Q�职业发展的最高点是“系�l�架构师”，Bill Gates不是�q�叫做微软的首席�pȝ��架构师吗�Q�System Architect职位需要的是你的学习和领悟能力�Q�如果你不能把学习Hibernate得到的设计经验运用到其它地方�Q�那么你是失败的�Q�也没有资格�?nbsp;System Architect�?nbsp;

不管JDO也好�Q�Hibernate也好�Q�TopLink也好�Q�CocoBase也好�Q�还�?nbsp;Castor�Q�还是什么Torque�Q�OJB�Q��Y件的使用和配�|�方法可以各异，但本质上都是ORM�Q�都是对JDBC的对象持久层��装�Q�所以万变不��d��宗，如果你完整的学习和掌握Hibernate�׃��1个月的时��_��那么你再学习OJB的时间不应该��过1个星期，因�ؓ你已�l�把对象持久层设计都了然于胸了，你需要的只是熟悉一下OJB的API和配�|��Ş了，至于怎么�q�用OJB�q�行持久层的开发你早就已经熟悉了�?nbsp;

所以当你掌握了两种以上的ORM�Q�你应该能够不拘于��用的ORM软�g的限�Ӟ��设计出适合于你的项目的持久层来�Q�这才是System Architect的水准。用金庸��说来打个比�Ҏ��说吧�Q�张无忌学太极剑�Q�只记剑意，不记剑招�Q�这才是真正的高手，而低手就只会��d��习剑招，而不去领会剑招背后蕴含的剑意�Q�所以一辈子都是低手�Q�永�q�不能真正学会太极剑。所以周颠看到张三丰�W�二�ơ演�C�太极剑�Q�招式完全不同就以�ؓ是另一套东西，其实本质上都一栗��学习Hibernate也不要舍本逐末的去学各�U�五花八门的工具�Q�重�Ҏ��握它的对象持久层设计理念�?

konhon 优华 2005-08-09 16:14 发表评论