我寫了一個服務器端應用程序,爲網站和多個移動客戶端提供動力。我使用Hibernate進行數據訪問。我後來發現應用程序在一天後失敗!當我在網上查了一下時,發現它在MySQL 8小時後終止一個「過時」連接的問題。爲了避免這種情況,我發現了很多建議,如包括?autoReconnect=true
,使用c3P0
等。 由於autoReconnect
已被官方勸阻(特別是在生產環境中),並且因爲它在應用時沒有任何影響,我決定去爲c3p0
。不幸的是,我的hibernate.cfg.xml
文件引入c3p0
配置後,應用程序啓動時拋出NullPointerException
地方在我的代碼,我叫dbSession.close()
這意味着HibernateUtil.getSessionFactory()
實際返回null
。我添加了所需的jar(c3p0-0.9.2-pre2.jar,hibernate-core-3.3.1.GA.jar,hibernate-c3p0-3.3.2.GA.jar,mchange-commons-java-0.2.1 .jar和c3p0-oracle-thin-extras-0.9.2-pre2.jar),儘管我不認爲它們都是必需的。 我已經瀏覽了很多討論過這個問題的網頁,但我仍然無法正確設置它。請幫助我使用「初學者友好型」易於實現的分步程序,用Hibernate設置c3p0
。我在JDK 1.6,MySQL 5.5上使用Hibernate 3.3.6,我在Netbeans 7.0中開發。休眠/ MySQL連接超時
這裏是我的hibernate.cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/religion_app</property>
<property name="hibernate.connection.username">*****</property>
<property name="hibernate.connection.password">*****</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="hibernate.query.factory_class">org.hibernate.hql.classic.ClassicQueryTranslatorFactory</property>
<property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="connection.autoReconnect">true</property>
<property name="connection.autoReconnectForPools">true</property>
<property name="connection.is-connection-validation-required">true</property>
<!-- configuration pool via c3p0-->
<property name="c3p0.acquire_increment">1</property>
<property name="c3p0.idle_test_period">120</property> <!-- seconds -->
<property name="c3p0.max_size">100</property>
<property name="c3p0.max_statements">0</property>
<property name="c3p0.min_size">10</property>
<property name="c3p0.timeout">180</property> <!-- seconds -->
<property name="c3p0.preferredTestQuery">select 1;</property>
<!--Mappings go here-->
</session-factory>
</hibernate-configuration>
這是我加入C3P0(不SLF4J)之後的了:
May 23, 2012 2:42:14 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet LoginChurch threw exception
java.lang.NullPointerException
at com.pacesolutions.religionapp.services.LoginChurch.processRequest(LoginChurch.java:109)
at com.pacesolutions.religionapp.services.LoginChurch.doPost(LoginChurch.java:138)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1555)
at java.lang.Thread.run(Thread.java:722)
May 23, 2012 2:45:13 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet LoginChurch threw exception
java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1516)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1361)
at org.hibernate.connection.C3P0ConnectionProvider.<clinit>(C3P0ConnectionProvider.java:52)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:525)
at java.lang.Class.newInstance0(Class.java:372)
at java.lang.Class.newInstance(Class.java:325)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:73)
at org.hibernate.connection.ConnectionProviderFactory.newConnectionProvider(ConnectionProviderFactory.java:56)
at org.hibernate.cfg.SettingsFactory.createConnectionProvider(SettingsFactory.java:414)
at org.hibernate.cfg.SettingsFactory.buildSettings(SettingsFactory.java:62)
at org.hibernate.cfg.Configuration.buildSettings(Configuration.java:2009)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1292)
at org.hibernate.cfg.AnnotationConfiguration.buildSessionFactory(AnnotationConfiguration.java:859)
at com.pacesolutions.religionapp.HibernateUtil.<clinit>(HibernateUtil.java:23)
at com.pacesolutions.religionapp.services.LoginChurch.processRequest(LoginChurch.java:68)
at com.pacesolutions.religionapp.services.LoginChurch.doPost(LoginChurch.java:143)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:859)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:579)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1555)
at java.lang.Thread.run(Thread.java:722)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.26 logs.
大部分由地方產生的Netbeans我的Hibernate配置文件。我在地面上有數據庫,然後使用Netbeans中的Hibernate嚮導來從中生成配置文件,實體類和映射文件。這些工作在我引入c3p0之前正常工作(但8小時後失敗)。 我在項目中使用了Mecurial,並將整個項目恢復到了我介紹c3p0之前的一段時間,它再次運行(8小時)。即使手動刪除hibernate.cfg.xml中的所有c3p0配置,也會使應用程序再次運行。 我可能做錯了什麼?
你能介紹一下NPE的stacktrace以及你使用Hibernate的模式(基本代表代碼示例)嗎? –