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我在GWT框架下用Hibernate設置Spring時遇到了問題。我對GWT相當陌生。我有應用程序上下文設置和加載沒有輸出錯誤，但我目前的主要問題是，我的服務層實現（PobaseServiceImpl）需要一個DAO，我在appcontext中設置，但它不包裝DAO。當然，我的RPC試圖調用導致NullPointerException的dao方法。當我初始化時，pobaseDao沒有被TransactionProxyFactoryBean設置。Spring TransactionProxyFactoryBean不爲服務加載dao
總結： DAO應該像我其他服務一樣通過（即配置）Spring來創建。然後通過Spring注入服務。然後用DAO把它包裝在Spring事務代理（org.springframework.transaction.interceptor.TransactionProxyFactoryBean）中並給它一個Hibernate SessionFactory（org.springframework.orm.hibernate4.LocalSessionFactoryBean）。但由於某種原因，它不設置道
所以我的應用程序上下文正在通過ServletContextListener加載。 這裏是我的應用程序上下文：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN//EN" "http://www.springframework.org/dtd/spring-beans.dtd">
<!--
Spring Framework application context definition for the POBASE Website.
-->
<beans>
<!-- Configurer that replaces ${...} placeholders with values from a properties file -->
<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>classpath:/pobase.properties</value>
<value>file:${user.home}/pobase.properties</value>
</list>
</property>
<property name="ignoreResourceNotFound" value="no"/>
</bean>
<!-- Hibernate Data Source -->
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="${pobase.database.driver}" />
<property name="url" value="${pobase.database.url}" />
<property name="username" value="${pobase.database.user}" />
<property name="password" value="${pobase.database.password}" />
</bean>
<!-- Hibernate SessionFactory -->
<bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
<property name="dataSource">
<ref bean="dataSource" />
</property>
<property name="packagesToScan" value="nz.co.doltech.pobase.client.entity"/>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">${pobase.hibernate.dialect}</prop>
<prop key="hibernate.show_sql">${pobase.hibernate.show_sql}</prop>
<prop key="javax.persistence.validation.mode">none</prop>
</props>
</property>
</bean>
<!-- Transaction manager for a single Hibernate SessionFactory (alternative to JTA) -->
<bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<!-- Default transaction proxy, defining the transactional behaviour for
a typical Dao configuration -->
<bean id="baseDaoTransactionProxy" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"
abstract="true">
<property name="transactionManager" ref="transactionManager" />
<property name="transactionAttributes">
<value>*=PROPAGATION_MANDATORY</value>
</property>
</bean>
<!-- Default transaction proxy, defining the transactional behaviour for
a typical Service configuration -->
<bean id="baseServiceTransactionProxy" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean"
abstract="true">
<property name="transactionManager" ref="transactionManager" />
<property name="transactionAttributes">
<value>*=PROPAGATION_REQUIRED</value>
</property>
</bean>
<!-- ========================= BUSINESS OBJECT DEFINITIONS ========================= -->
<bean id="pobaseDao" parent="baseDaoTransactionProxy">
<property name="target" ref="pobaseDaoTarget" />
</bean>
<bean id="pobaseDaoTarget" class="nz.co.doltech.pobase.server.dao.PobaseHibernateDao">
<property name="sessionFactory" ref="sessionFactory" />
</bean>
<bean id="pobaseService" parent="baseServiceTransactionProxy">
<property name="target" ref="pobaseServiceTarget" />
</bean>
<bean id="pobaseServiceTarget" class="nz.co.doltech.pobase.server.service.PobaseServiceImpl">
<property name="pobaseDao" ref="pobaseDao" />
<!-- property name="accessControlService" ref="accessControlService" />
<property name="lookupService" ref="lookupService"/>
<property name="notificationService" ref="notificationService"/ -->
</bean>
</beans>
，這裏是我的RPC Servlet實現：
package nz.co.doltech.pobase.server.service;
/**
* Extends RSS and implements the PobaseService
* @author Ben
*/
@SuppressWarnings("serial")
public class PobaseServiceImpl extends RemoteServiceServlet implements PobaseService {
@SuppressWarnings("unused")
private static final Logger logger = Logger.getLogger(PobaseServiceImpl.class.getName());
private PobaseDao pobaseDao;
private final HashMap<Integer, PobaseEntity> pobaseEntities = new HashMap<Integer, PobaseEntity>();
private void fetchExternPobase()
{
pobaseEntities.clear();
List<PobaseEntity> pobaseList = pobaseDao.getAllPobase();
for (int i = 0; i < pobaseList.size(); i++)
{
PobaseEntity en = pobaseList.get(i);
if(en != null) {
pobaseEntities.put(en.getId(), en);
}
}
}
public void setPobaseDao(PobaseDao dao)
{
this.pobaseDao = dao;
}
public PobaseDao getPobaseDao()
{
return this.pobaseDao;
}
public PobaseData addLocalPobase(PobaseData pobase)
{
PobaseEntity entity = new PobaseEntity();
entity.mirrorObjectData(pobase);
pobase.setId(pobaseEntities.size());
pobaseEntities.put(pobase.getId(), entity);
return entity.getDataObject();
}
public PobaseData updateLocalPobase(PobaseData pobase)
{
PobaseEntity entity = new PobaseEntity();
entity.mirrorObjectData(pobase);
pobaseEntities.remove(entity.getId());
pobaseEntities.put(entity.getId(), entity);
return entity.getDataObject();
}
public Boolean deleteLocalPobase(int id)
{
pobaseEntities.remove(id);
return true;
}
public ArrayList<PobaseData> deleteLocalPobases(ArrayList<Integer> ids)
{
for (int i = 0; i < ids.size(); ++i) {
deleteLocalPobase(ids.get(i));
}
return getLocalPobaseData();
}
public ArrayList<PobaseData> getLocalPobaseData()
{
ArrayList<PobaseData> pobaseList = new ArrayList<PobaseData>();
Iterator<Integer> it = pobaseEntities.keySet().iterator();
while(it.hasNext())
{
PobaseData pobase = pobaseEntities.get(it.next()).getDataObject();
pobaseList.add(pobase);
}
return pobaseList;
}
public PobaseData getLocalPobase(int id)
{
return pobaseEntities.get(id).getDataObject();
}
public ArrayList<PobaseData> resyncExternPobase()
{
fetchExternPobase();
return getLocalPobaseData();
}
}
而且這裏是啓動日誌對於Web應用程序：
ServletContextListener started
Nov 12, 2012 8:20:33 PM nz.co.doltech.pobase.SpringInitialiser initSpringContext
INFO: Creating new Spring context. Configs are [/nz/co/doltech/pobase/appcontext.xml]
Nov 12, 2012 8:20:33 PM org.springframework.context.support.AbstractApplicationContext prepareRefresh
INFO: Refreshing org[email protected]8423321: startup date [Mon Nov 12 20:20:33 NZDT 2012]; root of context hierarchy
Nov 12, 2012 8:20:33 PM org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
INFO: Loading XML bean definitions from class path resource [nz/co/doltech/pobase/appcontext.xml]
Nov 12, 2012 8:20:33 PM org.springframework.core.io.support.PropertiesLoaderSupport loadProperties
INFO: Loading properties file from class path resource [pobase.properties]
Nov 12, 2012 8:20:33 PM org.springframework.core.io.support.PropertiesLoaderSupport loadProperties
INFO: Loading properties file from URL [file:/home/ben/pobase.properties]
Nov 12, 2012 8:20:33 PM org.springframework.beans.factory.support.DefaultListableBeanFactory preInstantiateSingletons
INFO: Pre-instantiating singletons in org.s[email protected]4c56666d: defining beans [org.springframework.beans.factory.config.PropertyPlaceholderConfigurer#0,dataSource,sessionFactory,transactionManager,baseDaoTransactionProxy,baseServiceTransactionProxy,pobaseDao,pobaseDaoTarget,pobaseService,pobaseServiceTarget]; root of factory hierarchy
Nov 12, 2012 8:20:33 PM org.springframework.jdbc.datasource.DriverManagerDataSource setDriverClassName
INFO: Loaded JDBC driver: org.postgresql.Driver
Nov 12, 2012 8:20:33 PM org.hibernate.annotations.common.Version <clinit>
INFO: HCANN000001: Hibernate Commons Annotations {4.0.1.Final}
Nov 12, 2012 8:20:33 PM org.hibernate.Version logVersion
INFO: HHH000412: Hibernate Core {4.1.7.Final}
Nov 12, 2012 8:20:33 PM org.hibernate.cfg.Environment <clinit>
INFO: HHH000206: hibernate.properties not found
Nov 12, 2012 8:20:33 PM org.hibernate.cfg.Environment buildBytecodeProvider
INFO: HHH000021: Bytecode provider name : javassist
Nov 12, 2012 8:20:34 PM org.hibernate.dialect.Dialect <init>
INFO: HHH000400: Using dialect: org.hibernate.dialect.PostgreSQLDialect
Nov 12, 2012 8:20:34 PM org.hibernate.engine.jdbc.internal.LobCreatorBuilder useContextualLobCreation
INFO: HHH000424: Disabling contextual LOB creation as createClob() method threw error : java.lang.reflect.InvocationTargetException
Nov 12, 2012 8:20:34 PM org.hibernate.engine.transaction.internal.TransactionFactoryInitiator initiateService
INFO: HHH000399: Using default transaction strategy (direct JDBC transactions)
Nov 12, 2012 8:20:34 PM org.hibernate.hql.internal.ast.ASTQueryTranslatorFactory <init>
INFO: HHH000397: Using ASTQueryTranslatorFactory
Nov 12, 2012 8:20:34 PM org.springframework.orm.hibernate4.HibernateTransactionManager afterPropertiesSet
INFO: Using DataSource [[email protected]c0d4] of Hibernate SessionFactory for HibernateTransactionManager
Starting Jetty on port 8888
任何人有任何想法，爲什麼它不工作？這裏的一些規格：
- 春3.2.0
- Hibernate4
- GWT SDK 2.4.0
感謝所有幫助我能！
乾杯， 本
請添加堆棧跟蹤，另外您確定要加載數據並將其保存在您的服務中嗎？ –
是否有更傳統的方式來存儲數據？我對GWT相當陌生，所以不能100％確定最佳實踐。 （將堆棧跟蹤添加到主帖子）null異常是由於在設置之前調用了pobaseDao。但據我瞭解，在appcontext.xml中配置的事務代理和服務bean應該照顧這個？ –
那麼，這取決於你的方法，但是當你想要執行像緩存一樣的東西時，將數據存儲在服務實現中是合理的，否則這不是一種好的方法。 –