如何在JSF中上传文件

编程入门行业动态更新时间:2024-10-26 12:31:06

本文介绍了如何在JSF中上传文件的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！问题描述

实际上，我正在创建一个使用JSF上传文件的应用程序.但是，每当我上传文件并单击发送时，它就会显示NullPointerException.我为该应用程序使用的代码是:

Actually I'm creating an application for uploading file using JSF. But whenever I upload a file and click send it shows NullPointerException. The code I have used for the application is:

使用战斧的JSF代码:

code for JSF using Tomahawk:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="f" uri="java.sun/jsf/core"%> <%@ taglib prefix="h" uri="java.sun/jsf/html"%> <%@ taglib prefix="t" uri="myfaces.apache/tomahawk"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "www.w3/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>Email Client Web Application</title> </head> <body> <f:view> <h:form> <h:panelGrid columns="3" id="basePanel" rules="rows" border="0"> <h:outputLabel>TO:</h:outputLabel> <h:inputText id="txtTo" size="50" required="true" requiredMessage="Recipient cannot be empty" value="#{MailSenderBean.to}"> <f:validator validatorId="userLibrary.validators.DefaultRecipientValidator" /> </h:inputText> <h:message for="txtTo" style="color:red"></h:message> <h:outputLabel>CC:</h:outputLabel> <h:inputText id="txtCC" size="50" value="#{MailSenderBean.cc}"> <f:validator validatorId="userLibrary.validators.DefaultRecipientValidator" /> </h:inputText> <h:message for="txtCC" style="color:red"></h:message> <h:outputLabel>BCC:</h:outputLabel> <h:inputText id="txtBCC" size="50" value="#{MailSenderBean.bcc}"> <f:validator validatorId="userLibrary.validators.DefaultRecipientValidator" /> </h:inputText> <h:message for="txtBCC" style="color:red"></h:message> <h:outputLabel>SUBJECT:</h:outputLabel> <h:inputText id="txtSubject" size="92" value="#{MailSenderBean.subject}"></h:inputText> <h:message for="txtSubject"></h:message> <h:outputLabel></h:outputLabel> <h:inputTextarea id="txtMessage" rows="10" cols="70" value="#{MailSenderBean.messageBody}"></h:inputTextarea> <h:message for="txtMessage"></h:message> </h:panelGrid> <div id="part2" style="position:fixed;left:85px"> <t:inputFileUpload id="file" value="#{MailSenderBean.uploadedFile}"></t:inputFileUpload> <h:message for="file" style="color: red;" /> <br><br> <h:commandButton id="btnSubmit" value="Send" action="#{MailSenderBean.send}"></h:commandButton> </div> </h:form>

java文件的代码:

code for java file:

public String send() { System.out.println("File type: " + uploadedFile.getContentType()); System.out.println("File name: " + uploadedFile.getName()); System.out.println("File size: " + uploadedFile.getSize() + " bytes"); String status = "fail"; Properties props = new Properties(); props.put("mail.smtp.host", "smtp.gmail"); props.put("mail.smtp.socketFactory.port", "465"); props.put("mail.smtp.socketFactory.class", "javax.ssl.SSLSocketFactory"); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.port", "465"); Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication("saikia.buddha", "b10Q@`z&0%"); } }); try { Message message = new MimeMessage(session); MimeBodyPart part1=new MimeBodyPart(); MimeBodyPart part2=new MimeBodyPart(); FileDataSource datasource=new FileDataSource((File) uploadedFile); message.setFrom(new InternetAddress("saikia.buddha@gmail", "BUDDHA SAIKIA")); message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(getTo())); message.setRecipients(Message.RecipientType.CC, InternetAddress.parse(getCc())); message.setRecipients(Message.RecipientType.BCC, InternetAddress.parse(getBcc())); message.setSubject(getSubject()); part1.setText(messageBody); part2.setDataHandler(new DataHandler(datasource)); try { part2.attachFile(datasource.getFile()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } Multipart multipart=new MimeMultipart(); multipart.addBodyPart(part1); multipart.addBodyPart(part2); message.setContent(multipart); Transport.send(message); status = "success"; } catch (MessagingException e) { throw new RuntimeException(e); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } return status; }

堆栈跟踪:

javax.faces.el.EvaluationException: org.apache.jasper.el.JspELException: /index.jsp(50,2) '#{MailSenderBean.send}' java.lang.NullPointerException at javax.facesponent._MethodExpressionToMethodBinding.invoke(_MethodExpressionToMethodBinding.java:96) at org.apache.myfaces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:100) at javax.facesponent.UICommand.broadcast(UICommand.java:120) at javax.facesponent.UIViewRoot._broadcastAll(UIViewRoot.java:937) at javax.facesponent.UIViewRoot.broadcastEvents(UIViewRoot.java:271) at javax.facesponent.UIViewRoot._process(UIViewRoot.java:1249) at javax.facesponent.UIViewRoot.processApplication(UIViewRoot.java:675) at org.apache.myfaces.lifecycle.InvokeApplicationExecutor.execute(InvokeApplicationExecutor.java:34) at org.apache.myfaces.lifecycle.LifecycleImpl.executePhase(LifecycleImpl.java:171) at org.apache.myfaces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:189) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:928) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:539) at org.apache.tomcat.util.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:298) 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) Caused by: org.apache.jasper.el.JspELException: /index.jsp(50,2) '#{MailSenderBean.send}' java.lang.NullPointerException at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:79) at javax.facesponent._MethodExpressionToMethodBinding.invoke(_MethodExpressionToMethodBinding.java:88) ... 26 more Caused by: java.lang.NullPointerException at userLibrary.MailSender.send(MailSender.java:81) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.el.parser.AstValue.invoke(AstValue.java:262) at org.apache.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:278) at org.apache.jasper.el.JspMethodExpression.invoke(JspMethodExpression.java:70) ... 27 more

推荐答案

<h:form>

您忘记按照战斧文档将表单的enctype设置为multipart/form-data.

You forgot to set the form's enctype to multipart/form-data as per Tomahawk documentation.

相应修复:

<h:form enctype="multipart/form-data">

请不要忘记在web.xml中也配置ExtensionsFilter，以便JSF可以处理上载的文件以及所有其他属性和操作.也就是说，当前的堆栈跟踪中缺少此过滤器.

Don't forget to configure the ExtensionsFilter in web.xml as well so that the uploaded file and all other properties and the action can be processed by JSF. This filter is namely missing in your current stack trace.

请注意，您在action方法中隐式地期望uploadedFile不是null.您可能想将required="true"添加到<t:inputFileUpload>组件中，否则当有人没有选择文件时，您会再次得到NullPointerException.

Note that you're in the action method implicitly expecting the uploadedFile to be not null. You would probably like to add required="true" to the <t:inputFileUpload> component, otherwise you will get a NullPointerException again when someone doesn't select a file.