J'essaie d'utiliser jnlp.FileSaveService pour "saveAs" fichier .txt généré dans contoroller de java web app. J'ai trouvé quelques exemples ici http://docs.oracle.com/javase/tutorial/deployment/doingMoreWithRIA/usingJNLPAPI.html Je ne comprends pas bien comment cela fonctionne et je reçois exception poniter null à cette ligne:Exception de pointeur nul jnlp.FileSaveService
fc = fss.saveFileDialog(null, null, new ByteArrayInputStream(txt.getBytes()), null);
Est-ce que je transmets quelque chose de mal à la méthode SaveFileDialog ou est-ce autre chose? J'apprécierais toute aide.
static private FileOpenService fos = null;
static private FileSaveService fss = null;
static private FileContents fc = null;
private static synchronized void initialize() {
try {
fos = (FileOpenService)ServiceManager.lookup("javax.jnlp.FileOpenService");
fss = (FileSaveService)ServiceManager.lookup("javax.jnlp.FileSaveService");
} catch (UnavailableServiceException e) {
}
}
public static void save(String txt) {
initialize();
try {
// Show save dialog if no name is already given
if (fc == null) {
fc = fss.saveFileDialog(null, null, new ByteArrayInputStream(txt.getBytes()), null);
// file saved, done
return;
}
// use this only when filename is known
if (fc != null) {
writeToFile(txt, fc);
}
} catch (IOException ioe) {ioe.printStackTrace(System.out);
}
}
public static void saveAs(String txt) {
initialize();
try {
if (fc == null) {
// If not already saved. Save-as is like save
save(txt);
} else {
fc = fss.saveAsFileDialog(null, null, fc);
save(txt);
}
} catch (IOException ioe) {
ioe.printStackTrace(System.out);
}
}
private static void writeToFile(String txt, FileContents fc) throws IOException {
int sizeNeeded = txt.length() * 2;
if (sizeNeeded > fc.getMaxLength()) {
fc.setMaxLength(sizeNeeded);
}
BufferedWriter os = new BufferedWriter(new OutputStreamWriter(fc.getOutputStream(true)));
os.write(txt);
os.close();
}
@RequestMapping(value = "/exportPhonebook.html", method = RequestMethod.POST)
public String exportPhonebook(Model model) {
List<User> listOfAllUsers = phoneBookSer.fetchAllUsers();
String phonebook = "";
for (User user : listOfAllUsers) {
phonebook = phonebook + user.getSurname() + " " + user.getName() +
", Phone Number: " + user.getPhoneNumber() + ";\r\n" ;
}
saveAs(phonebook);
}
Voici stacktrace
20.03.2013. 13:19:41 org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [springDipatcher] in context with path [/phonebook] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
at phonebook.controllers.ExportPhonebook.save(ExportPhonebook.java:80)
at phonebook.controllers.ExportPhonebook.saveAs(ExportPhonebook.java:97)
at phonebook.controllers.ExportPhonebook.exportPhonebook(ExportPhonebook.java:129)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:436)
at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:424)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:790)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:328)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:95)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:175)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
1) Je suggère * toujours * passer la méthode un nom de fichier. Même si l'utilisateur décide de le changer, il peut être là comme une suggestion. 2) Faites un 'System.out.println()' sur l'attribut 'fc' et' txt' immédiatement avant cette ligne. AFAIU c'est un de ces 2, ou le nom du fichier, c'est le problème. 3) Voir aussi [démo du service de fichiers.] (Http://pscode.org/jws/api.html#fs) pour un exemple pratique. –
J'ai changé le nom du fichier de null à "phonebook.txt". System.out.println (txt); fonctionne bien, mais System.out.println (fc); imprime seulement "null". Je suppose que ce problème est dans cet attribut fc, mais je ne sais pas comment le réparer ou quoi changer. –
* "à la fois sur l'attribut' fc' "* Désolé, je voulais dire l'attribut' fss' ici. A fait la démo. travailler pour vous? –