Hibernate3
提供了DetachedCriteria,使得我们可以在Web层构造detachedCriteria,然后调用业务层Bean,进行动态条件查询,根
据这一功能,我设计了通用的抽象Bean基类和分页类支持,代码来自于Quake
Wang的javaeye-core包的相应类,然后又做了很多修改。
分页支持类:
java代码:
|
package com.javaeye.common.util;
import java.util.List;
publicclass PaginationSupport {
publicfinalstaticint PAGESIZE = 30;
privateint pageSize = PAGESIZE;
privateList items;
privateint totalCount;
privateint[] indexes = newint[0];
privateint 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);
}
publicList getItems(){
return items;
}
publicvoid setItems(List items){
this.items = items;
}
publicint getPageSize(){
return pageSize;
}
publicvoid setPageSize(int pageSize){
this.pageSize = pageSize;
}
publicint getTotalCount(){
return totalCount;
}
publicvoid setTotalCount(int totalCount){
if(totalCount > 0){
this.totalCount = totalCount;
int count = totalCount / pageSize;
if(totalCount % pageSize > 0)
count++;
indexes = newint[count];
for(int i = 0; i < count; i++){
indexes[i] = pageSize * i;
}
}else{
this.totalCount = 0;
}
}
publicint[] getIndexes(){
return indexes;
}
publicvoid setIndexes(int[] indexes){
this.indexes = indexes;
}
publicint getStartIndex(){
return startIndex;
}
publicvoid setStartIndex(int startIndex){
if(totalCount <= 0)
this.startIndex = 0;
elseif(startIndex >= totalCount)
this.startIndex = indexes[indexes.length - 1];
elseif(startIndex < 0)
this.startIndex = 0;
else{
this.startIndex = indexes[startIndex / pageSize];
}
}
publicint getNextIndex(){
int nextIndex = getStartIndex() + pageSize;
if(nextIndex >= totalCount)
return getStartIndex();
else
return nextIndex;
}
publicint getPreviousIndex(){
int previousIndex = getStartIndex() - pageSize;
if(previousIndex < 0)
return0;
else
return previousIndex;
}
}
|
抽象业务类
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;
publicabstractclass AbstractManager extends HibernateDaoSupport {
privateboolean cacheQueries = false;
privateString queryCacheRegion;
publicvoid setCacheQueries(boolean cacheQueries){
this.cacheQueries = cacheQueries;
}
publicvoid setQueryCacheRegion(String queryCacheRegion){
this.queryCacheRegion = queryCacheRegion;
}
publicvoid save(finalObject entity){
getHibernateTemplate().save(entity);
}
publicvoid persist(finalObject entity){
getHibernateTemplate().save(entity);
}
publicvoid update(finalObject entity){
getHibernateTemplate().update(entity);
}
publicvoid delete(finalObject entity){
getHibernateTemplate().delete(entity);
}
publicObject load(finalClass entity, finalSerializable id){
return getHibernateTemplate().load(entity, id);
}
publicObject get(finalClass entity, finalSerializable id){
return getHibernateTemplate().get(entity, id);
}
publicList findAll(finalClass entity){
return getHibernateTemplate().find("from " + entity.getName());
}
publicList findByNamedQuery(finalString namedQuery){
return getHibernateTemplate().findByNamedQuery(namedQuery);
}
publicList findByNamedQuery(finalString query, finalObject parameter){
return getHibernateTemplate().findByNamedQuery(query, parameter);
}
publicList findByNamedQuery(finalString query, finalObject[] parameters){
return getHibernateTemplate().findByNamedQuery(query, parameters);
}
publicList find(finalString query){
return getHibernateTemplate().find(query);
}
publicList find(finalString query, finalObject parameter){
return getHibernateTemplate().find(query, parameter);
}
public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria){
return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE, 0);
}
public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria, finalint startIndex){
return findPageByCriteria(detachedCriteria, PaginationSupport.PAGESIZE, startIndex);
}
public PaginationSupport findPageByCriteria(final DetachedCriteria detachedCriteria, finalint pageSize,
finalint startIndex){
return(PaginationSupport) getHibernateTemplate().execute(new HibernateCallback(){
publicObject 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);
}
publicList findAllByCriteria(final DetachedCriteria detachedCriteria){
return(List) getHibernateTemplate().execute(new HibernateCallback(){
publicObject doInHibernate(Session session)throws HibernateException {
Criteria criteria = detachedCriteria.getExecutableCriteria(session);
return criteria.list();
}
}, true);
}
publicint getCountByCriteria(final DetachedCriteria detachedCriteria){
Integer count = (Integer) getHibernateTemplate().execute(new HibernateCallback(){
publicObject 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,和可选的startIndex,调用业务bean的相应findByCriteria方法,返回一个PaginationSupport的实例ps。
ps.getItems()得到已分页好的结果集
ps.getIndexes()得到分页索引的数组
ps.getTotalCount()得到总结果数
ps.getStartIndex()当前分页索引
ps.getNextIndex()下一页索引
ps.getPreviousIndex()上一页索引
连续看了两篇robbin有关DetachedCriteria的介绍,感觉真的不错,尤其是上面的示例代码,让我着实觉得该对我原来的分页查询做一下代码重构了。
我把原本我的做法也提供出来供大家讨论吧:
首先,为了实现分页查询,我封装了一个Page类:
java代码:
|
/*Created on 2005-4-14*/
package org.flyware.util.page;
/**
* @author Joa
*
*/ publicclass Page {
/** imply if the page has previous page */
privateboolean hasPrePage;
/** imply if the page has next page */
privateboolean hasNextPage;
/** the number of every page */
privateint everyPage;
/** the total page number */
privateint totalPage;
/** the number of current page */
privateint currentPage;
/** the begin index of the records by the current query */
privateint beginIndex;
/** The default constructor */
public Page(){
}
/** construct the page by everyPage
* @param everyPage
* */
public Page(int everyPage){
this.everyPage = everyPage;
}
/** The whole constructor */
public Page(boolean hasPrePage, boolean hasNextPage,
int everyPage, int totalPage,
int currentPage, int beginIndex){
this.hasPrePage = hasPrePage;
this.hasNextPage = hasNextPage;
this.everyPage = everyPage;
this.totalPage = totalPage;
this.currentPage = currentPage;
this.beginIndex = beginIndex;
}
/**
* @return
* Returns the beginIndex.
*/
publicint getBeginIndex(){
return beginIndex;
}
/**
* @param beginIndex
* The beginIndex to set.
*/
publicvoid setBeginIndex(int beginIndex){
this.beginIndex = beginIndex;
}
/**
* @return
* Returns the currentPage.
*/
publicint getCurrentPage(){
return currentPage;
}
/**
* @param currentPage
* The currentPage to set.
*/
publicvoid setCurrentPage(int currentPage){
this.currentPage = currentPage;
}
/**
* @return
* Returns the everyPage.
*/
publicint getEveryPage(){
return everyPage;
}
/**
* @param everyPage
* The everyPage to set.
*/
publicvoid setEveryPage(int everyPage){
this.everyPage = everyPage;
}
/**
* @return
* Returns the hasNextPage.
*/
publicboolean getHasNextPage(){
return hasNextPage;
}
/**
* @param hasNextPage
* The hasNextPage to set.
*/
publicvoid setHasNextPage(boolean hasNextPage){
this.hasNextPage = hasNextPage;
}
/**
* @return
* Returns the hasPrePage.
*/
publicboolean getHasPrePage(){
return hasPrePage;
}
/**
* @param hasPrePage
* The hasPrePage to set.
*/
publicvoid setHasPrePage(boolean hasPrePage){
this.hasPrePage = hasPrePage;
}
/**
* @return Returns the totalPage.
*
*/
publicint getTotalPage(){
return totalPage;
}
/**
* @param totalPage
* The totalPage to set.
*/
publicvoid setTotalPage(int totalPage){
this.totalPage = totalPage;
}
}
|
上面的这个Page类对象只是一个完整的Page描述,接下来我写了一个PageUtil,负责对Page对象进行构造:
java代码:
|
/*Created on 2005-4-14*/
package org.flyware.util.page;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
/**
* @author Joa
*
*/ publicclass PageUtil {
privatestaticfinal Log logger = LogFactory.getLog(PageUtil.class);
/**
* Use the origin page to create a new page
* @param page
* @param totalRecords
* @return
*/
publicstatic Page createPage(Page page, int totalRecords){
return createPage(page.getEveryPage(), page.getCurrentPage(), totalRecords);
}
/**
* the basic page utils not including exception handler
* @param everyPage
* @param currentPage
* @param totalRecords
* @return page
*/
publicstatic Page createPage(int everyPage, int currentPage, int totalRecords){
everyPage = getEveryPage(everyPage);
currentPage = getCurrentPage(currentPage);
int beginIndex = getBeginIndex(everyPage, currentPage);
int totalPage = getTotalPage(everyPage, totalRecords);
boolean hasNextPage = hasNextPage(currentPage, totalPage);
boolean hasPrePage = hasPrePage(currentPage);
returnnew Page(hasPrePage, hasNextPage,
everyPage, totalPage,
currentPage, beginIndex);
}
privatestaticint getEveryPage(int everyPage){
return everyPage == 0 ? 10 : everyPage;
}
privatestaticint getCurrentPage(int currentPage){
return currentPage == 0 ? 1 : currentPage;
}
privatestaticint getBeginIndex(int everyPage, int currentPage){
return(currentPage - 1) * everyPage;
}
privatestaticint getTotalPage(int everyPage, int totalRecords){
int totalPage = 0;
if(totalRecords % everyPage == 0)
totalPage = totalRecords / everyPage;
else
totalPage = totalRecords / everyPage + 1 ;
return totalPage;
}
privatestaticboolean hasPrePage(int currentPage){
return currentPage == 1 ? false : true;
}
privatestaticboolean hasNextPage(int currentPage, int totalPage){
return currentPage == totalPage || totalPage == 0 ? false : true;
}
}
|
上面的这两个对象与具体的业务逻辑无关,可以独立和抽象。
面对一个具体的业务逻辑:分页查询出User,每页10个结果。具体做法如下:
1. 编写一个通用的结果存储类Result,这个类包含一个Page对象的信息,和一个结果集List:
java代码:
|
/*Created on 2005-6-13*/
package com.adt.bo;
import java.util.List;
import org.flyware.util.page.Page;
/**
* @author Joa
*/ publicclass Result {
private Page page;
privateList content;
/**
* The default constructor
*/
public Result(){
super();
}
/**
* The constructor using fields
*
* @param page
* @param content
*/
public Result(Page page, List content){
this.page = page;
this.content = content;
}
/**
* @return Returns the content.
*/
publicList getContent(){
return content;
}
/**
* @return Returns the page.
*/
public Page getPage(){
return page;
}
/**
* @param content
* The content to set.
*/
publicvoid setContent(List content){
this.content = content;
}
/**
* @param page
* The page to set.
*/
publicvoid setPage(Page page){
this.page = page;
} }
|
2. 编写业务逻辑接口,并实现它(UserManager, UserManagerImpl)
java代码:
|
/*Created on 2005-7-15*/
package com.adt.service;
import net.sf.hibernate.HibernateException;
import org.flyware.util.page.Page;
import com.adt.bo.Result;
/**
* @author Joa
*/ publicinterface UserManager {
public Result listUser(Page page)throws HibernateException;
}
|
java代码:
|
/*Created on 2005-7-15*/
package com.adt.service.impl;
import java.util.List;
import net.sf.hibernate.HibernateException;
import org.flyware.util.page.Page;
import org.flyware.util.page.PageUtil;
import com.adt.bo.Result;
import com.adt.dao.UserDAO;
import com.adt.exception.ObjectNotFoundException;
import com.adt.service.UserManager;
/**
* @author Joa
*/ publicclass UserManagerImpl implements UserManager {
private UserDAO userDAO;
/**
* @param userDAO The userDAO to set.
*/
publicvoid setUserDAO(UserDAO userDAO){
this.userDAO = userDAO;
}
/* (non-Javadoc)
* @see com.adt.service.UserManager#listUser(org.flyware.util.page.Page)
*/
public Result listUser(Page page)throws HibernateException, ObjectNotFoundException {
int totalRecords = userDAO.getUserCount();
if(totalRecords == 0)
throw new ObjectNotFoundException("userNotExist");
page = PageUtil.createPage(page, totalRecords);
List users = userDAO.getUserByPage(page);
returnnew Result(page, users);
}
}
|
其中,UserManagerImpl中调用userDAO的方法实现对User的分页查询,接下来编写UserDAO的代码:
3. UserDAO 和 UserDAOImpl:
java代码:
|
/*Created on 2005-7-15*/
package com.adt.dao;
import java.util.List;
import org.flyware.util.page.Page;
import net.sf.hibernate.HibernateException;
/**
* @author Joa
*/ publicinterface UserDAO extends BaseDAO {
publicList getUserByName(String name)throws HibernateException;
publicint getUserCount()throws HibernateException;
publicList getUserByPage(Page page)throws HibernateException;
}
|
java代码:
|
/*Created on 2005-7-15*/
package com.adt.dao.impl;
import java.util.List;
import org.flyware.util.page.Page;
import net.sf.hibernate.HibernateException;
import net.sf.hibernate.Query;
import com.adt.dao.UserDAO;
/**
* @author Joa
*/ publicclass UserDAOImpl extends BaseDAOHibernateImpl implements UserDAO {
/* (non-Javadoc)
* @see com.adt.dao.UserDAO#getUserByName(java.lang.String)
*/
publicList getUserByName(String name)throws HibernateException {
String querySentence = "FROM user in class com.adt.po.User WHERE user.name=:name";
Query query = getSession().createQuery(querySentence);
query.setParameter("name", name);
return query.list();
}
/* (non-Javadoc)
* @see com.adt.dao.UserDAO#getUserCount()
*/
publicint getUserCount()throws HibernateException {
int count = 0;
String querySentence = "SELECT count(*) FROM user in class com.adt.po.User";
Query query = getSession().createQuery(querySentence);
count = ((Integer)query.iterate().next()).intValue();
return count;
}
/* (non-Javadoc)
* @see com.adt.dao.UserDAO#getUserByPage(org.flyware.util.page.Page)
*/
publicList getUserByPage(Page page)throws HibernateException {
String querySentence = "FROM user in class com.adt.po.User";
Query query = getSession().createQuery(querySentence);
query.setFirstResult(page.getBeginIndex())
.setMaxResults(page.getEveryPage());
return query.list();
}
}
|
至此,一个完整的分页程序完成。前台的只需要调用userManager.listUser(page)即可得到一个Page对象和结果集对象的综合体,而传入的参数page对象则可以由前台传入,如果用webwork,甚至可以直接在配置文件中指定。
下面给出一个webwork调用示例:
java代码:
|
/*Created on 2005-6-17*/
package com.adt.action.user;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.flyware.util.page.Page;
import com.adt.bo.Result;
import com.adt.service.UserService;
import com.opensymphony.xwork.Action;
/**
* @author Joa
*/ publicclass ListUser implementsAction{
privatestaticfinal Log logger = LogFactory.getLog(ListUser.class);
private UserService userService;
private Page page;
privateList users;
/*
* (non-Javadoc)
*
* @see com.opensymphony.xwork.Action#execute()
*/
publicString execute()throwsException{
Result result = userService.listUser(page);
page = result.getPage();
users = result.getContent();
return SUCCESS;
}
/**
* @return Returns the page.
*/
public Page getPage(){
return page;
}
/**
* @return Returns the users.
*/
publicList getUsers(){
return users;
}
/**
* @param page
* The page to set.
*/
publicvoid setPage(Page page){
this.page = page;
}
/**
* @param users
* The users to set.
*/
publicvoid setUsers(List users){
this.users = users;
}
/**
* @param userService
* The userService to set.
*/
publicvoid setUserService(UserService userService){
this.userService = userService;
} }
|
上面的代码似乎看不出什么地方设置了page的相关初值,事实上,可以通过配置文件来进行配置,例如,我想每页显示10条记录,那么只需要:
java代码:
|
<?xml version="1.0"?>
<!DOCTYPE xwork PUBLIC "-//OpenSymphony Group//XWork 1.0//EN" "http://www.opensymphony.com/xwork/xwork-1.0.dtd">
<xwork>
<package name="user" extends="webwork-interceptors">
<!-- The default interceptor stack name -->
<default-interceptor-ref name="myDefaultWebStack"/>
<action name="listUser" class="com.adt.action.user.ListUser">
<param name="page.everyPage">10</param>
<result name="success">/user/user_list.jsp</result>
</action>
</package>
</xwork>
|
这样就可以通过配置文件和OGNL的共同作用来对page对象设置初值了。并可以通过随意修改配置文件来修改每页需要显示的记录数。
注:上面的<param>的配置,还需要webwork和Spring整合的配合。
我写的一个用于分页的类,用了泛型了,hoho
java代码:
|
package com.intokr.util;
import java.util.List;
/**
* 用于分页的类<br>
* 可以用于传递查询的结果也可以用于传送查询的参数<br>
*
* @version 0.01
* @author cheng
*/ publicclass Paginator<E> {
privateint count = 0; // 总记录数
privateint p = 1; // 页编号
privateint num = 20; // 每页的记录数
privateList<E> results = null; // 结果
/**
* 结果总数
*/
publicint getCount(){
return count;
}
publicvoid setCount(int count){
this.count = count;
}
/**
* 本结果所在的页码,从1开始
*
* @return Returns the pageNo.
*/
publicint getP(){
return p;
}
/**
* if(p<=0) p=1
*
* @param p
*/
publicvoid setP(int p){
if(p <= 0)
p = 1;
this.p = p;
}
/**
* 每页记录数量
*/
publicint getNum(){
return num;
}
/**
* if(num<1) num=1
*/
publicvoid setNum(int num){
if(num < 1)
num = 1;
this.num = num;
}
/**
* 获得总页数
*/
publicint getPageNum(){
return(count - 1) / num + 1;
}
/**
* 获得本页的开始编号,为 (p-1)*num+1
*/
publicint getStart(){
return(p - 1) * num + 1;
}
/**
* @return Returns the results.
*/
publicList<E> getResults(){
return results;
}
publicvoid setResults(List<E> results){
this.results = results;
}
publicString toString(){
StringBuilder buff = new StringBuilder();
buff.append("{");
buff.append("count:").append(count);
buff.append(",p:").append(p);
buff.append(",nump:").append(num);
buff.append(",results:").append(results);
buff.append("}");
return buff.toString();
}
}
|
偷窥自 http://forum.javaeye.com/
|