一个DAO 一个Interface 搞定spring ＋ hibernate＋动态hql查询

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spring

DAO Hibernate Spring Bean ORM

找了一些spring的文章看了下，有所启发，于是大概的总结了下，希望大家多提提意见

为了实现自己程序对spring和hibernate的过分依赖，因此自己写了一个接口，封装了8个常用的数据库操作

接口如下

java 代码

package com.pig.dao;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import org.springframework.dao.DataAccessException;
/**
* 实现具体数据访问的接口,该接口将程序和框架进行了分离,提供了抽象出来的几个常用的方法优点：减少了对spring，hibernate的依赖
* 缺点：提供了有限的几个方法，可能造成提供的方法不全
*
* @author lizhihui
* @see DAOInterfaceHibernate3Imp
*/
public interface DAOInterface {
/**
* Persist the given transient instance.
* @param entity the transient instance to persist
* @return the generated identifier
*/
public Serializable save(Object entity);
/**
* Save or update the given persistent instance,
* according to its id (matching the configured "unsaved-value"?).
* @param entity the persistent instance to save or update
* (to be associated with the Hibernate Session)
* @throws DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#saveOrUpdate(Object)
*/
public void saveOrUpdate(Object entity) throws DataAccessException;
/**
* Save or update all given persistent instances,
* according to its id (matching the configured "unsaved-value"?).
* @param entities the persistent instances to save or update
* (to be associated with the Hibernate Session)
* @throws DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#saveOrUpdate(Object)
*/
public void saveOrUpdate(Collection entities) throws DataAccessException;
/**
* Delete the given persistent instance.
* @param entity the persistent instance to delete
* @throws org.springframework.dao.DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#delete(Object)
*/
public void delete(Object entity) throws DataAccessException;
/**
* Delete the instance according to identifier
* @param c class of instance
* @param id identifier
* @throws org.springframework.dao.DataAccessException in case of Hibernate errors
*/
public void delete(Class c, Serializable id) throws DataAccessException;
/**
* Delete all given persistent instances.
*
This can be combined with any of the find methods to delete by query
* in two lines of code, similar to Session's delete by query methods.
* @param entities the persistent instances to delete
* @throws org.springframework.dao.DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#delete(String)
*/
public void delete(Collection entities) throws DataAccessException;
/**
* Return the persistent instance of the given entity class
* with the given identifier, throwing an exception if not found.
*
This method is a thin wrapper around
* {@link net.sf.hibernate.Session#load(Class, java.io.Serializable)} for convenience.
* For an explanation of the exact semantics of this method, please do refer to
* the Hibernate API documentation in the first instance.
* @param entityClass a persistent class
* @param id an identifier of the persistent instance
* @return the persistent instance
* @throws org.springframework.orm.ObjectRetrievalFailureException if not found
* @throws org.springframework.dao.DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#load(Class, java.io.Serializable)
*/
public Object load(Class entityClass, Serializable id) throws DataAccessException;
/**
* Execute an HQL query
* @param queryString a query expressed in Hibernate's query language
* @return a List containing the results of the query execution
* @throws org.springframework.dao.DataAccessException in case of Hibernate errors
* @see net.sf.hibernate.Session#find(String, Object[], net.sf.hibernate.type.Type[])
* @see net.sf.hibernate.Session#createQuery
*/
public List find(String queryString) throws DataAccessException;
}

他的实现

java 代码

package com.pig.dao;
import java.io.Serializable;
import java.sql.SQLException;
import java.util.Collection;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.springframework.dao.DataAccessException;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;
public class DAOInterfaceHibernate3Imp extends HibernateDaoSupport implements DAOInterface {
private static Log log=LogFactory.getLog(DAOInterfaceHibernate3Imp.class);
public void delete(Object entity) throws DataAccessException {
getHibernateTemplate().delete(entity);
}
public void delete(Class c, Serializable id) throws DataAccessException {
Object entiry = load(c, id);
getHibernateTemplate().delete(entiry);
}
public void delete(Collection entities) throws DataAccessException {
getHibernateTemplate().deleteAll(entities);
}
public List find(String queryString) throws DataAccessException {
return getHibernateTemplate().find(queryString);
}
public Object load(Class entityClass, Serializable id) throws DataAccessException {
return getHibernateTemplate().load(entityClass, id);
}
public Serializable save(Object entity) {
return getHibernateTemplate().save(entity);
}
public void saveOrUpdate(Object entity) throws DataAccessException {
getHibernateTemplate().saveOrUpdate(entity);
}
public void saveOrUpdate(Collection entities) throws DataAccessException {
getHibernateTemplate().saveOrUpdateAll(entities);
}
}

这样如果 hibernate如果有了变得只改变他的实现类就可以了，甚至可以改变成其他的中间件实现

在程序中只用了实现了一个DAO，感觉他可以对所以的类操作了，至于其他的和业务相关联的操作例如用户登陆，修改秘密等操作我把他们归结到了 service中，这样service的实现可能要好多的类和接口

大家看下我的DAO

java 代码

package com.pig.dao;
import java.io.Serializable;
import java.util.Collection;
import java.util.List;
import org.springframework.dao.DataAccessException;
import com.pig.util.PropertyResource;
public class BasicDAO {
private DAOInterface dao;
private PropertyResource sqlMapping;
public BasicDAO(){
}
public void delete(Object entity) throws DataAccessException {
dao.delete(entity);
}
public void delete(Class c, Serializable id) throws DataAccessException {
dao.delete(c,id);
}
public void delete(Collection entities) throws DataAccessException {
dao.delete(entities);
}
public List find(String queryStringKey,Object[] args) throws DataAccessException {
return dao.find(sqlMapping.getFormattedString(queryStringKey, args));
}
public Object load(Class entityClass, Serializable id) throws DataAccessException {
return dao.load(entityClass, id);
}
public Serializable save(Object entity) {
return dao.save(entity);
}
public void saveOrUpdate(Object entity) throws DataAccessException {
dao.saveOrUpdate(entity);
}
public void saveOrUpdate(Collection entities) throws DataAccessException {
dao.saveOrUpdate(entities);
}
}

在这个DAO中注入了一个DAOInterface 和一个properties 文件这个文件可以根据key来找到对应的hql 或者sql语句并将参数格式化进去，看下这个方法

java 代码

public List find(String queryStringKey,Object[] args) throws DataAccessException {
return dao.find(sqlMapping.getFormattedString(queryStringKey, args));
}

这个方法直接根据给定的hql语句查询出结果集。本来还想给出一个根据hql来更新数据库的操作，但是发现hibernate好像没有提供这个接口（我对hibernate的了解还不是很多）

下面将读取hql文件的的类也一并给出大家参考下把，这个hql文件应该放到classpath下

java 代码

package com.pig.util;
import java.text.MessageFormat;
import java.util.*;
/**
* read properties file in classpath
* @author lzh
* @version 1.0
*/
public class PropertyResource {
private String resourceName;
private Locale locale;
private Map<String, String> properties;
public PropertyResource() {
}
private void init() {
if (properties == null) {
properties = new Hashtable<String, String>();
ResourceBundle rb = null;
if (locale == null) {
rb = ResourceBundle.getBundle(resourceName);
} else {
rb = ResourceBundle.getBundle(resourceName, locale);
}
Enumeration<String> e = rb.getKeys();
String key = null;
String value = null;
while (e.hasMoreElements()) {
key = e.nextElement();
value = rb.getString(key);
properties.put(key, value);
}
}
}
public String getString(String key) {
if (properties == null) {
init();
}
return properties.get(key);
}
public String getString(String key, String defaultValue) {
if (properties == null) {
init();
}
String value = properties.get(key);
return value == null ? defaultValue : value;
}
public String getFormattedString(String key, Object args[]) {
String msg = MessageFormat.format(getString(key), args);
return msg;
}
public Locale getLocale() {
return locale;
}
public void setLocale(Locale locale) {
this.locale = locale;
}
public String getResourceName() {
return resourceName;
}
public void setResourceName(String resourceName) {
this.resourceName = resourceName;
}
}

最后大家看下我spring的配置文件把，这个配置文件还配置了对事务的管理（参考了他人的做法）

java 代码

<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource"/>
<property name="mappingResources">
<list>
</list>
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${hibernate.dialect}</prop>
<prop key="hibernate.show_sql">true</prop>
<prop key="hibernate.generate_statistics">true</prop>
</props>
</property>
<property name="eventListeners">
<map>
<entry key="merge">
<bean class="org.springframework.orm.hibernate3.support.IdTransferringMergeEventListener"/>
</entry>
</map>
</property>
</bean>
<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="transactionInterceptor" class="org.springframework.transaction.interceptor.TransactionInterceptor">
<property name="transactionManager" ref="transactionManager" />
<property name="transactionAttributes">
<props>
<prop key="insert*">PROPAGATION_REQUIRED</prop>
<prop key="find*">PROPAGATION_REQUIRED,readOnly</prop>
<prop key="*">PROPAGATION_REQUIRED</prop>
</props>
</property>
</bean>
<bean class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
<property name="beanNames">
<value>*DAO,*Service</value>
</property>
<property name="interceptorNames">
<list>
<value>transactionInterceptor</value>
</list>
</property>
</bean>
<bean id="daoInterface" class="com.pig.dao.DAOInterfaceHibernate3Imp">
<property name="sessionFactory" ref="sessionFactory"/>
</bean>
<bean id="sqlPropertyResource" class="com.pig.util.PropertyResource">
<property name="resourceName" value="com.pig.resource"/>
</bean>
<bean id="basicDAO" class="com.pig.dao.BasicDAO">
<property name="dao" ref="daoInterface"/>
<property name="sqlMapping" ref="sqlPropertyResource"/>
</bean>

希望大家能多提意见，偶对spring才看了没几天，看了大家的贴子，可以说是照葫芦画瓢见笑见笑

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j2sdk1.4.0中bin子目录下各程序的参数用法 | tomcat 中开启https服务

2007-03-14 22:11
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评论(6)
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分类:企业架构
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6 楼 sun_cat 2007-03-15

昨天晚上本来打算上传附件的可是老是上传不上去
偶是刚开始学spring 希望大家多多指教

5 楼 eyejava 2007-03-15

BasicDAO 包装DAOInterface 还真有点怪怪的,只是多了一个find方法而已.
另外hql 放在配置文件里面运行期间的参数接收将很麻烦.
appgen 已经提供生成dao代码的模版, 这些重复的代码都可以不用手工写的.

4 楼 jfy3d 2007-03-15

我也这么用不过是Ｉｂａｔｉｓ的
因为SQL在SQLMAP 里功能应该比ResourceBundle更多些
连service也简化了

普通GRUD的service
只要
public UserService extends BaseService {
}
就可以了

单DAO 确实提高很大生产速度

3 楼 daoger 2007-03-15

这是常用的配置方式中的一种，希望LZ进一步研究，能有更好的文章分享！

2 楼 huangpengxiao 2007-03-15

严重同意楼上

1 楼 lighter 2007-03-14

1、建议楼主打包一下程序，方便看一下，这样拉下来，看得头昏
2、“搞定spring ＋ hibernate＋动态hql查询”有标题党的嫌疑，有时间看清楚后再回复你的帖子

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