我目前在netbeans中使用java开发Web应用程序。我将JPA2.0与H2数据库一起使用。
问题是当我更改数据库中的数据并在浏览器中重新加载页面时=>未设置更改。
只有当我重新运行jsp中的netbeans页面，或者我重新启动tomcat：
的web.xml：
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>ajoutAutomobile</servlet-name>
<servlet-class>controlleurs.ajoutAutomobile</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutConducteur</servlet-name>
<servlet-class>controlleurs.ajoutConducteur</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutMission</servlet-name>
<servlet-class>controlleurs.ajoutMission</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutUtilisateur</servlet-name>
<servlet-class>controlleurs.ajoutUtilisateur</servlet-class>
</servlet>
<servlet>
<servlet-name>selectCinConducteur</servlet-name>
<servlet-class>controlleurs.selectCinConducteur</servlet-class>
</servlet>
<servlet>
<servlet-name>selectIdAuto</servlet-name>
<servlet-class>controlleurs.selectIdAuto</servlet-class>
</servlet>
<servlet>
<servlet-name>selectIdAutomobile</servlet-name>
<servlet-class>controlleurs.selectIdAutomobile</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutVignette</servlet-name>
<servlet-class>controlleurs.ajoutVignette</servlet-class>
</servlet>
<servlet>
<servlet-name>selectImei</servlet-name>
<servlet-class>controlleurs.selectImei</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutAssurance</servlet-name>
<servlet-class>controlleurs.ajoutAssurance</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutVisite</servlet-name>
<servlet-class>controlleurs.ajoutVisite</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutIntervention</servlet-name>
<servlet-class>controlleurs.ajoutIntervention</servlet-class>
</servlet>
<servlet>
<servlet-name>selectAutoLibre</servlet-name>
<servlet-class>controlleurs.selectAutoLibre</servlet-class>
</servlet>
<servlet>
<servlet-name>selectConducteurLibre</servlet-name>
<servlet-class>controlleurs.selectConducteurLibre</servlet-class>
</servlet>
<servlet>
<servlet-name>afficheInfoGeo</servlet-name>
<servlet-class>controlleurs.afficheInfoGeo</servlet-class>
</servlet>
<servlet>
<servlet-name>ajoutAffectation</servlet-name>
<servlet-class>controlleurs.ajoutAffectation</servlet-class>
</servlet>
<servlet>
<servlet-name>afficheListConducteur</servlet-name>
<servlet-class>controlleurs.afficheListConducteur</servlet-class>
</servlet>
<servlet>
<servlet-name>afficheInfoGeoRestreinte</servlet-name>
<servlet-class>controlleurs.afficheInfoGeoRestreinte</servlet-class>
</servlet>
<servlet>
<servlet-name>selectDate</servlet-name>
<servlet-class>controlleurs.selectDate</servlet-class>
</servlet>
<servlet>
<servlet-name>selectCoordsRestreinte</servlet-name>
<servlet-class>controlleurs.selectCoordsRestreinte</servlet-class>
</servlet>
<servlet>
<servlet-name>selectAssuranceExpir</servlet-name>
<servlet-class>controlleurs.selectAssuranceExpir</servlet-class>
</servlet>
<servlet>
<servlet-name>selectVignetteExpir</servlet-name>
<servlet-class>controlleurs.selectVignetteExpir</servlet-class>
</servlet>
<servlet>
<servlet-name>selectVisiteExpir</servlet-name>
<servlet-class>controlleurs.selectVisiteExpir</servlet-class>
</servlet>
<servlet>
<servlet-name>selectAssurance</servlet-name>
<servlet-class>controlleurs.selectAssurance</servlet-class>
</servlet>
<servlet>
<servlet-name>selectVignette</servlet-name>
<servlet-class>controlleurs.selectVignette</servlet-class>
</servlet>
<servlet>
<servlet-name>selectVisite</servlet-name>
<servlet-class>controlleurs.selectVisite</servlet-class>
</servlet>
<servlet>
<servlet-name>afficheListAutomobile</servlet-name>
<servlet-class>controlleurs.afficheListAutomobile</servlet-class>
</servlet>
<servlet>
<servlet-name>historiqueAffectationConducteur</servlet-name>
<servlet-class>controlleurs.historiqueAffectationConducteur</servlet-class>
</servlet>
<servlet>
<servlet-name>historiqueAffectationAutomobile</servlet-name>
<servlet-class>controlleurs.historiqueAffectationAutomobile</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ajoutAutomobile</servlet-name>
<url-pattern>/ajoutAutomobile</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutConducteur</servlet-name>
<url-pattern>/ajoutConducteur</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutMission</servlet-name>
<url-pattern>/ajoutMission</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutUtilisateur</servlet-name>
<url-pattern>/ajoutUtilisateur</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectCinConducteur</servlet-name>
<url-pattern>/selectCinConducteur</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectIdAuto</servlet-name>
<url-pattern>/selectIdAuto</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectIdAutomobile</servlet-name>
<url-pattern>/selectIdAutomobile</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutVignette</servlet-name>
<url-pattern>/ajoutVignette</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectImei</servlet-name>
<url-pattern>/selectImei</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutAssurance</servlet-name>
<url-pattern>/ajoutAssurance</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutVisite</servlet-name>
<url-pattern>/ajoutVisite</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutIntervention</servlet-name>
<url-pattern>/ajoutIntervention</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectAutoLibre</servlet-name>
<url-pattern>/selectAutoLibre</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectConducteurLibre</servlet-name>
<url-pattern>/selectConducteurLibre</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>afficheInfoGeo</servlet-name>
<url-pattern>/afficheInfoGeo</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>ajoutAffectation</servlet-name>
<url-pattern>/ajoutAffectation</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>afficheListConducteur</servlet-name>
<url-pattern>/afficheListConducteur</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>afficheInfoGeoRestreinte</servlet-name>
<url-pattern>/afficheInfoGeoRestreinte</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectDate</servlet-name>
<url-pattern>/selectDate</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectCoordsRestreinte</servlet-name>
<url-pattern>/selectCoordsRestreinte</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectAssuranceExpir</servlet-name>
<url-pattern>/selectAssuranceExpir</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectVignetteExpir</servlet-name>
<url-pattern>/selectVignetteExpir</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectVisiteExpir</servlet-name>
<url-pattern>/selectVisiteExpir</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectAssurance</servlet-name>
<url-pattern>/selectAssurance</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectVignette</servlet-name>
<url-pattern>/selectVignette</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>selectVisite</servlet-name>
<url-pattern>/selectVisite</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>afficheListAutomobile</servlet-name>
<url-pattern>/afficheListAutomobile</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>historiqueAffectationConducteur</servlet-name>
<url-pattern>/historiqueAffectationConducteur</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>historiqueAffectationAutomobile</servlet-name>
<url-pattern>/historiqueAffectationAutomobile</url-pattern>
</servlet-mapping>
<session-config>
<session-timeout>
30
</session-timeout>
</session-config>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
server.xml中：
<?xml version='1.0' encoding='utf-8'?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<!-- Note: A "Server" is not itself a "Container", so you may not
define subcomponents such as "Valves" at this level.
Documentation at /docs/config/server.html
-->
<Server port="8005" shutdown="SHUTDOWN">
<!--APR library loader. Documentation at /docs/apr.html -->
<Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
<!--Initialize Jasper prior to webapps are loaded. Documentation at /docs/jasper-howto.html -->
<Listener className="org.apache.catalina.core.JasperListener" />
<!-- Prevent memory leaks due to use of particular java/javax APIs-->
<Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
<!-- JMX Support for the Tomcat server. Documentation at /docs/non-existent.html -->
<Listener className="org.apache.catalina.mbeans.ServerLifecycleListener" />
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
<!-- Global JNDI resources
Documentation at /docs/jndi-resources-howto.html
-->
<GlobalNamingResources>
<!-- Editable user database that can also be used by
UserDatabaseRealm to authenticate users
-->
<Resource name="UserDatabase" auth="Container"
type="org.apache.catalina.UserDatabase"
description="User database that can be updated and saved"
factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>
<!-- A "Service" is a collection of one or more "Connectors" that share
a single "Container" Note: A "Service" is not itself a "Container",
so you may not define subcomponents such as "Valves" at this level.
Documentation at /docs/config/service.html
-->
<Service name="Catalina">
<!--The connectors can use a shared executor, you can define one or more named thread pools-->
<!--
<Executor name="tomcatThreadPool" namePrefix="catalina-exec-"
maxThreads="150" minSpareThreads="4"/>
-->
<!-- A "Connector" represents an endpoint by which requests are received
and responses are returned. Documentation at :
Java HTTP Connector: /docs/config/http.html (blocking & non-blocking)
Java AJP Connector: /docs/config/ajp.html
APR (HTTP/AJP) Connector: /docs/apr.html
Define a non-SSL HTTP/1.1 Connector on port 8080
-->
<Connector port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
<!-- A "Connector" using the shared thread pool-->
<!--
<Connector executor="tomcatThreadPool"
port="8080" protocol="HTTP/1.1"
connectionTimeout="20000"
redirectPort="8443" />
-->
<!-- Define a SSL HTTP/1.1 Connector on port 8443
This connector uses the JSSE configuration, when using APR, the
connector should be using the OpenSSL style configuration
described in the APR documentation -->
<!--
<Connector port="8443" protocol="HTTP/1.1" SSLEnabled="true"
maxThreads="150" scheme="https" secure="true"
clientAuth="false" sslProtocol="TLS" />
-->
<!-- Define an AJP 1.3 Connector on port 8009 -->
<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
<!-- An Engine represents the entry point (within Catalina) that processes
every request. The Engine implementation for Tomcat stand alone
analyzes the HTTP headers included with the request, and passes them
on to the appropriate Host (virtual host).
Documentation at /docs/config/engine.html -->
<!-- You should set jvmRoute to support load-balancing via AJP ie :
<Engine name="Catalina" defaultHost="localhost" jvmRoute="jvm1">
-->
<Engine name="Catalina" defaultHost="localhost">
<!--For clustering, please take a look at documentation at:
/docs/cluster-howto.html (simple how to)
/docs/config/cluster.html (reference documentation) -->
<!--
<Cluster className="org.apache.catalina.ha.tcp.SimpleTcpCluster"/>
-->
<!-- The request dumper valve dumps useful debugging information about
the request and response data received and sent by Tomcat.
Documentation at: /docs/config/valve.html -->
<!--
<Valve className="org.apache.catalina.valves.RequestDumperValve"/>
-->
<!-- This Realm uses the UserDatabase configured in the global JNDI
resources under the key "UserDatabase". Any edits
that are performed against this UserDatabase are immediately
available for use by the Realm. -->
<Realm className="org.apache.catalina.realm.UserDatabaseRealm"
resourceName="UserDatabase"/>
<!-- Define the default virtual host
Note: XML Schema validation will not work with Xerces 2.2.
-->
<Host name="localhost" appBase="webapps"
unpackWARs="true" autoDeploy="true"
xmlValidation="false" xmlNamespaceAware="false">
<!-- SingleSignOn valve, share authentication between web applications
Documentation at: /docs/config/valve.html -->
<!--
<Valve className="org.apache.catalina.authenticator.SingleSignOn" />
-->
<!-- Access log processes all example.
Documentation at: /docs/config/valve.html -->
<!--
<Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
prefix="localhost_access_log." suffix=".txt" pattern="common" resolveHosts="false"/>
-->
</Host>
</Engine>
</Service>
</Server>
请问如何解决这个问题？
编辑：我试图删除缓存，也在其他浏览器中打开页面=＆gt;相同的结果..
EDIT2 ： 的persistence.xml：
<?xml version="1.0" encoding="UTF-8"?>
<persistence version="2.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="webPU" transaction-type="RESOURCE_LOCAL">
<provider>org.eclipse.persistence.jpa.PersistenceProvider</provider>
<class>entities.Automobile</class>
<class>entities.Intervention</class>
<class>entities.Assurance</class>
<class>entities.Coordonnees</class>
<class>entities.Mission</class>
<class>entities.Affectation</class>
<class>entities.Conducteur</class>
<class>entities.Gps</class>
<class>entities.Vignette</class>
<class>entities.Utilisateur</class>
<class>entities.VisiteTechnique</class>
<exclude-unlisted-classes>false</exclude-unlisted-classes>
<properties>
<property name="javax.persistence.jdbc.url" value="jdbc:h2:tcp://localhost/~/ApiGps"/>
<property name="javax.persistence.jdbc.password" value=""/>
<property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
<property name="javax.persistence.jdbc.user" value="sa"/>
</properties>
</persistence-unit>
</persistence>
我的servlet：
response.setContentType("application/json");
PrintWriter out = response.getWriter();
EntityManagerFactory emf=Persistence.createEntityManagerFactory("webPU");
Timestamp nd=new Timestamp(System.currentTimeMillis());//now
nd.setMinutes(nd.getMinutes()-20);
EntityManager em=emf.createEntityManager();
String req="select a from Automobile a where a.gpsImei.imei in (SELECT c.gpsImei.imei FROM Coordonnees c WHERE c.date < :nd )";
Query resultat=em.createQuery(req);
resultat.setParameter("nd", nd);
java.util.List<Automobile> la= resultat.getResultList();
Gson gson=new Gson();
String json =gson.toJson(La);//convert the List to json
try {
out.println(json);//return respons to ajax
} finally {
out.close();
}
答案 0 :(得分：2)
由于您使用的是transaction-type="RESOURCE_LOCAL"
您始终只想使用一个EntityManager。拥有一个在您的应用程序中管理相同EntityManager实例的父类。
拥有多个实例几乎绝不是一个好主意 正在使用的EntityManager（除非你有，否则不要创建第二个） 摧毁了第一个）
我认为问题在于在这里创建一个新的EM
EntityManager em=emf.createEntityManager();
就个人而言，我更喜欢使用事务类型，transaction-type =“TRANSACTION”，而不用担心实体经理https://stackoverflow.com/a/1963012/643500
您可以在此处阅读更多内容http://openejb.apache.org/jpa-concepts.html
保存数据时，是使用saveOrUpdate还是合并？
这可能不是正确的答案，但我希望它有所帮助。