public class DatabaseHelper {
@Autowired
static UtilService utilService;
public static void fillEmptyTables(){
if(!isSkillsInDatabase()){
utilService.addGeneratedSkill();
}
if(!isEventTypesInDatabase()){
utilService.addGeneratedEventType();
}
if(!isEventStatusesInDatabase()){
utilService.addGeneratedEventStatus();
}
}
public static boolean isSkillsInDatabase(){
return utilService.getAllSkills().size() != 0;
}
public static boolean isEventStatusesInDatabase(){
return utilService.getAllEventStatuses().size() != 0;
}
public static boolean isEventTypesInDatabase(){
return utilService.getAllEventTypes().size() != 0;
}
}
< /code>
и этот прослушиватель: < /p>
@WebListener
public class ApplicationWebListener implements ServletContextListener {
@Override
public void contextDestroyed(ServletContextEvent arg0) {
System.out.println("ServletContextListener destroyed");
}
@Override
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("ServletContextListener started");
DatabaseHelper.fillEmptyTables();
}
}
< /code>
Когда я запускаю свое приложение, я вижу следующее: < /p>
INFO : org.springframework.web.context.ContextLoader - Root WebApplicationContext: initialization completed in 10029 ms
ServletContextListener started
22.10.2013 13:21:16 org.apache.catalina.core.StandardContext listenerStart
SEVERE: Exception sending context initialized event to listener instance of class com.epam.hhsystem.web.controllers.ApplicationWebListener
java.lang.NullPointerException
at com.epam.hhsystem.util.DatabaseHelper.isSkillsInDatabase(DatabaseHelper.java:25)
at com.epam.hhsystem.util.DatabaseHelper.fillEmptyTables(DatabaseHelper.java:13)
at com.epam.hhsystem.web.controllers.ApplicationWebListener.contextInitialized(ApplicationWebListener.java:19)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4887)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5381)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)
22.10.2013 13:21:16 org.apache.catalina.core.StandardContext startInternal
SEVERE: Error listenerStart
@WebListener
public class ApplicationWebListener implements ServletContextListener {
@Override
public void contextDestroyed(ServletContextEvent arg0) {
System.out.println("ServletContextListener destroyed");
}
@Override
public void contextInitialized(ServletContextEvent arg0) {
System.out.println("ServletContextListener started");
}
}
< /code>
Этот код работает хорошо. Когда я запускаю свое приложение, я вижу:
ServletContextListener запустил
Местоположение utilService:
Подробнее здесь: [url]https://stackoverflow.com/questions/19513947/exception-sending-context-initialized-event-to-listener-instance-of-class[/url]
} public static boolean isSkillsInDatabase(){ return utilService.getAllSkills().size() != 0; } public static boolean isEventStatusesInDatabase(){ return utilService.getAllEventStatuses().size() != 0; } public static boolean isEventTypesInDatabase(){ return utilService.getAllEventTypes().size() != 0; } } < /code> и этот прослушиватель: < /p> @WebListener public class ApplicationWebListener implements ServletContextListener { @Override public void contextDestroyed(ServletContextEvent arg0) { System.out.println("ServletContextListener destroyed"); }
@Override public void contextInitialized(ServletContextEvent arg0) { System.out.println("ServletContextListener started"); DatabaseHelper.fillEmptyTables(); } } < /code> Когда я запускаю свое приложение, я вижу следующее: < /p> INFO : org.springframework.web.context.ContextLoader - Root WebApplicationContext: initialization completed in 10029 ms ServletContextListener started 22.10.2013 13:21:16 org.apache.catalina.core.StandardContext listenerStart SEVERE: Exception sending context initialized event to listener instance of class com.epam.hhsystem.web.controllers.ApplicationWebListener java.lang.NullPointerException at com.epam.hhsystem.util.DatabaseHelper.isSkillsInDatabase(DatabaseHelper.java:25) at com.epam.hhsystem.util.DatabaseHelper.fillEmptyTables(DatabaseHelper.java:13) at com.epam.hhsystem.web.controllers.ApplicationWebListener.contextInitialized(ApplicationWebListener.java:19) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4887) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5381) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:662) 22.10.2013 13:21:16 org.apache.catalina.core.StandardContext startInternal SEVERE: Error listenerStart [/code] Какова причина этой проблемы? Как это исправить?[code]
< /code> и это: < /p>
< /code> и это: < /p>
[/code] [b] update [/b] [code]@WebListener public class ApplicationWebListener implements ServletContextListener { @Override public void contextDestroyed(ServletContextEvent arg0) { System.out.println("ServletContextListener destroyed"); }
@Override public void contextInitialized(ServletContextEvent arg0) { System.out.println("ServletContextListener started"); } } < /code> Этот код работает хорошо. Когда я запускаю свое приложение, я вижу: