javamail 将图像添加到 html 电子邮件中。如何？

Question

我使用 javamail 发送电子邮件没有问题(我使用 EJB 3.0)，问题是当我尝试通过使用多部分方法向 html 添加一些图像时。出于某种原因，我得到一个 FileNotFoundException。我不知道如何获取位于 WEB-INF/resources/images 的 .png 图像的路径。

这是我做的:

Message message = new MimeMessage(mailSession);
        // From: is our service
        message.setFrom(new InternetAddress(from));
        // To: destination given
        message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse(to));
        message.setSubject("Uspijesna registracija");
        // How to found at http://www.rgagnon.com/javadetails/java-0321.html
        message.setContent(generateActivationLinkTemplate(), "text/html");

        Date timeStamp = new Date();
        message.setSentDate(timeStamp);

        // Prepare a multipart HTML
        Multipart multipart = new MimeMultipart("related");
        // Prepare the HTML
        BodyPart htmlPart = new MimeBodyPart();
        htmlPart.setContent(generateActivationLinkTemplate(), "text/html");
        multipart.addBodyPart(htmlPart);
        // PREPARE THE IMAGE
        BodyPart imgPart = new MimeBodyPart();
        DataSource ds = new FileDataSource("logomailtemplate.png");
        imgPart.setDataHandler(new DataHandler(ds));
        imgPart.setHeader("Content-ID", "the-img-1");
        multipart.addBodyPart(imgPart);
        // Set the message content!
        message.setContent(multipart);

        Transport.send(message);

文本来自另一种方法，可以正常工作。我认为问题出在这行代码中:

DataSource ds = new FileDataSource("logomailtemplate.png");

控制台是这样说的:

java.io.FileNotFoundException: logomailtemplate.png (The system cannot find the file specified)

我如何访问该图像？它位于 WEB-INF/resources/images我被这个病困住了，真的很感谢你的帮助:)

--------------------------------更新------------ ----------------------

Message message = new MimeMessage(mailSession);
        // From: is our service
        message.setFrom(new InternetAddress(from));
        // To: destination given
        message.setRecipients(Message.RecipientType.TO,
                InternetAddress.parse(to));
        message.setSubject("Uspijesna registracija");
        // How to found at http://www.rgagnon.com/javadetails/java-0321.html
        message.setContent(generateActivationLinkTemplate(), "text/html");

        Date timeStamp = new Date();
        message.setSentDate(timeStamp);

        // Prepare a multipart HTML
        Multipart multipart = new MimeMultipart();
        // Prepare the HTML
        BodyPart htmlPart = new MimeBodyPart();
        htmlPart.setContent(generateActivationLinkTemplate(), "text/html");
        multipart.addBodyPart(htmlPart);
        // PREPARE THE IMAGE
        BodyPart imgPart = new MimeBodyPart();

        String fileName = "WEB-INF/resources/images/logoemailtemplate.png";
        InputStream stream = null;
        ClassLoader classLoader = Thread.currentThread()
                .getContextClassLoader();
        if (classLoader == null) {
            classLoader = this.getClass().getClassLoader();
        }
        stream = classLoader.getResourceAsStream(fileName);
        DataSource ds = new ByteArrayDataSource(stream, "image/*");             

        imgPart.setDataHandler(new DataHandler(ds));
        imgPart.setHeader("Content-ID", "the-img-1");
        multipart.addBodyPart(imgPart);
        // Set the message content!
        message.setContent(multipart);

        Transport.send(message);

----------------------------------------堆栈跟踪--- --------------------------------

WARNING: StandardWrapperValve[Faces Servlet]: PWC1406: Servlet.service() for servlet Faces Servlet threw exception javax.faces.el.EvaluationException: javax.ejb.EJBException ................

SEVERE: javax.ejb.EJBException javax.faces.el.EvaluationException: javax.ejb.EJBException at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:102) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102) at javax.faces.component.UICommand.broadcast(UICommand.java:315) at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:775) at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1267) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:82) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312) at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188) at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641) at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97) at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185) at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226) at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165) at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791) at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693) at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954) at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170) at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102) at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88) at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76) at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53) at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57) at com.sun.grizzly.ContextTask.run(ContextTask.java:69) at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330) at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309) at java.lang.Thread.run(Thread.java:662) Caused by: javax.ejb.EJBException at com.sun.ejb.containers.BaseContainer.processSystemException(BaseContainer.java:5119) at com.sun.ejb.containers.BaseContainer.completeNewTx(BaseContainer.java:5017) at com.sun.ejb.containers.BaseContainer.postInvokeTx(BaseContainer.java:4805) at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:2004) at com.sun.ejb.containers.BaseContainer.postInvoke(BaseContainer.java:1955) at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:198) at com.sun.ejb.containers.EJBLocalObjectInvocationHandlerDelegate.invoke(EJBLocalObjectInvocationHandlerDelegate.java:84) at $Proxy162.sendAccountActivationLinkToBuyer(Unknown Source) at managedbeans.RegistrationController.doRegisterBuyer(RegistrationController.java:64) 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 com.sun.el.parser.AstValue.invoke(AstValue.java:234) at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297) at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:43) at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:72) at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:98) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:88) ... 32 more

Caused by: java.lang.NullPointerException at javax.mail.util.ByteArrayDataSource.(ByteArrayDataSource.java:83) at ejbs.EmailServiceEJB.sendAccountActivationLinkToBuyer(EmailServiceEJB.java:69) 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.glassfish.ejb.security.application.EJBSecurityManager.runMethod(EJBSecurityManager.java:1056) at org.glassfish.ejb.security.application.EJBSecurityManager.invoke(EJBSecurityManager.java:1128) at com.sun.ejb.containers.BaseContainer.invokeBeanMethod(BaseContainer.java:5292) at com.sun.ejb.EjbInvocation.invokeBeanMethod(EjbInvocation.java:615) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797) at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:567) at org.jboss.weld.ejb.SessionBeanInterceptor.aroundInvoke(SessionBeanInterceptor.java:47) 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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:858) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797) at com.sun.ejb.EjbInvocation.proceed(EjbInvocation.java:567) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.doAround(SystemInterceptorProxy.java:157) at com.sun.ejb.containers.interceptors.SystemInterceptorProxy.aroundInvoke(SystemInterceptorProxy.java:139) 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 com.sun.ejb.containers.interceptors.AroundInvokeInterceptor.intercept(InterceptorManager.java:858) at com.sun.ejb.containers.interceptors.AroundInvokeChainImpl.invokeNext(InterceptorManager.java:797) at com.sun.ejb.containers.interceptors.InterceptorManager.intercept(InterceptorManager.java:367) at com.sun.ejb.containers.BaseContainer.__intercept(BaseContainer.java:5264) at com.sun.ejb.containers.BaseContainer.intercept(BaseContainer.java:5252) at com.sun.ejb.containers.EJBLocalObjectInvocationHandler.invoke(EJBLocalObjectInvocationHandler.java:190) ... 45 more

--------------------------------更新 2------------ --------------------------------

String fileName = "/WEB-INF/resources/images/logoemailtemplate.png";
        InputStream stream = null;
        ClassLoader classLoader = Thread.currentThread()
                .getContextClassLoader();
        if (classLoader == null) {
            classLoader = this.getClass().getClassLoader();
        }
        //This line dont work!
        stream = classLoader.getResourceAsStream(fileName);                                                 


        DataSource ds = new    URLDataSource(classLoader.getResource(fileName));

//DataSource ds = new FileDataSource(new File(classLoader // .getResource(fileName).toURI())); Also dont work. Also i tried both / and without /

Answer 1

实现此目的的一种方法是:

DataSource ds = new ByteArrayDataSource(getServletContext().getResourceAsStream("WEB-INF/resources/images/logomailtemplate.png") ,mimeType);

getServletContext().getResourceAsStream() 从 HttpServlet 接收并返回一个 InputStream。

---

最好还是这样做

String fileName = "/WEB-INF/resources/images/logomailtemplate.png";
InputStream stream = getServletContext().getResourceAsStream(fileName); //or null if you can't obtain a ServletContext

if (stream == null) {
    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    if (classLoader == null) {
        classLoader = this.getClass().getClassLoader();
    }

    stream = classLoader.getResourceAsStream(fileName);
}

DataSource ds = new ByteArrayDataSource(stream, "image/*");

---

更新

或者

String fileName = "WEB-INF/resources/images/logomailtemplate.png";
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
if (classLoader == null) {
    classLoader = this.getClass().getClassLoader();
}

DataSource ds = new FileDataSource(new File(classLoader.getResource(fileName).toURI()));

//OR
DataSource ds = new URLDataSource(classLoader.getResource(fileName));

确保您的 fileName 以“/”开头。