爲什麼tomcat在數據庫中看不到更新？

Question

我目前在NetBeans中我用java開發一個web應用程序。我用H2數據庫使用JPA2.0。

問題是，當我更改數據庫中的數據並重新加載瀏覽器中的頁面時=>未設置更改。 只有當我在netbeans重新運行jsp頁面，或者我重新啓動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> 

的server.xml：

<?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> 

如何解決這個問題嗎？

編輯：我試圖刪除緩存，而且在其他瀏覽器=>相同的結果打開網頁..

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(); 
     } 

Answer 1

由於您使用的是transaction-type="RESOURCE_LOCAL"

您一直只想使用一個EntityManager。有一個父類，可以跨應用程序管理相同的EntityManager實例。

這幾乎是從來就沒有使用中的 的EntityManager的多個實例是一個好主意（不創建第二個，除非你已經 破壞第一）

我想問題是在這裏創建一個新的EM

EntityManager em=emf.createEntityManager(); 

就個人而言，我更喜歡使用的交易類型，交易類型爲「TRANSACTION」，不用擔心實體管理器https://stackoverflow.com/a/1963012/643500

當你保存你使用saveOrUpdate或者合併數據，您可以在這裏閱讀更多http://openejb.apache.org/jpa-concepts.html

？

這可能不是正確的答案，但我希望它有幫助。