使用Spring 3.0，我编写了一个界面来隐藏应用程序，我用它来发送邮件的模板引擎。界面是
public interface MailSender {
public void send(String[] to, String from, String subject, String template,
Map<Object, Object> model, boolean isHtml,
Map<String, Resource> attachments,
Map<String, Resource> inline) throws MailException;
}
然后Velocity实现
public class MailSenderVelocity implements MailSender {
private JavaMailSender sender;
private VelocityEngine engine;
@Override
public void send(final String[] to, final String from,
final String subject, final String template,
final Map<Object, Object> model, final boolean isHtml,
final Map<String, Resource> attachments,
final Map<String, Resource> inline)
throws com.engrid.mail.MailException {
try {
// prepare the message to send
MimeMessagePreparator preparator = new MimeMessagePreparator() {
@Override
public void prepare(MimeMessage mimeMessage) throws Exception {
// determine if the message needs to be multipart or not
boolean multipart = (attachments != null && !attachments.isEmpty()) || (inline != null && !inline.isEmpty());
// create the message
MimeMessageHelper helper = new MimeMessageHelper(mimeMessage, multipart);
// populate header fields
helper.setTo(to);
helper.setFrom(from);
helper.setSubject(subject);
// fetch template and merge model
String text = VelocityEngineUtils.mergeTemplateIntoString(engine, template, model);
helper.setText(text, isHtml);
// add inline attachments
if (inline != null) {
for (Entry<String, Resource> entry : inline.entrySet()) {
helper.addInline(entry.getKey(), entry.getValue());
}
}
// add other attachments
if (attachments != null) {
for (Entry<String, Resource> entry : attachments.entrySet()) {
helper.addAttachment(entry.getKey(), entry.getValue());
}
}
}
};
// send the email
this.sender.send(preparator);
} catch(MailException e) {
// error preparing or sending the message
e.printStackTrace();
throw new com.engrid.mail.MailException(e);
}
}
public void setSender(JavaMailSender sender) {
this.sender = sender;
}
public void setEngine(VelocityEngine engine) {
this.engine = engine;
}
}
作为一名优秀的程序员，我为不同的场景编写了测试用例，以确保一切正常。我的一个案例是指定了附件但文件本身不存在，特别是
@Test(expected=MailException.class)
public void testSend_MissingAttachment() throws IOException, MailException {
// create new object
MailSenderVelocity testSender = new MailSenderVelocity();
testSender.setEngine(engine);
testSender.setSender(sender);
// assign properties
String subject = "testSend_MissingAttachment";
String template = "simple.vm";
Map<Object, Object> model = new HashMap<Object, Object>();
model.put("user", "User");
boolean isHtml = true;
Map<String, Resource> attachments = new HashMap<String, Resource>();
String file = "notext.txt";
attachments.put(file, templateDirectory.createRelative(file));
Map<String, Resource> inline = null;
// send a message -- will fail because it won't find the file to attach
testSender.send(this.to, this.from, subject, template, model, isHtml, attachments, inline);
}
现在，测试会导致抛出预期的异常
org.springframework.mail.MailSendException: Failed messages: javax.mail.MessagingException: IOException while sending message;
nested exception is:
java.io.FileNotFoundException: class path resource [com/company/mail/template/notext.txt] cannot be opened because it does not exist; message exception details (1) are:
Failed message 1:
javax.mail.MessagingException: IOException while sending message;
nested exception is:
java.io.FileNotFoundException: class path resource [com/company/mail/template/notext.txt] cannot be opened because it does not exist
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:625)
at org.springframework.mail.javamail.JavaMailSenderImpl.doSend(JavaMailSenderImpl.java:416)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:340)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:355)
at org.springframework.mail.javamail.JavaMailSenderImpl.send(JavaMailSenderImpl.java:344)
at com.company.mail.MailSenderVelocity.send(MailSenderVelocity.java:103)
at com.company.mail.MailSenderVelocity.send(MailSenderVelocity.java:53)
at com.company.mail.MailSenderVelocityTest.testSend_MissingAttachment(MailSenderVelocityTest.java:136)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:48)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
at java.lang.reflect.Method.invoke(Method.java:600)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:22)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:82)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:45)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:460)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:673)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:386)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:196)
Caused by: java.io.FileNotFoundException: class path resource [com/company/mail/template/notext.txt] cannot be opened because it does not exist
at org.springframework.core.io.ClassPathResource.getInputStream(ClassPathResource.java:158)
at org.springframework.mail.javamail.MimeMessageHelper$1.getInputStream(MimeMessageHelper.java:1086)
at javax.activation.DataHandler.writeTo(DataHandler.java:302)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1350)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:845)
at javax.mail.internet.MimeMultipart.writeTo(MimeMultipart.java:361)
at com.sun.mail.handlers.multipart_mixed.writeTo(multipart_mixed.java:85)
at javax.activation.ObjectDataContentHandler.writeTo(DataHandler.java:881)
at javax.activation.DataHandler.writeTo(DataHandler.java:314)
at javax.mail.internet.MimeBodyPart.writeTo(MimeBodyPart.java:1350)
at javax.mail.internet.MimeMessage.writeTo(MimeMessage.java:1683)
at com.sun.mail.smtp.SMTPTransport.sendMessage(SMTPTransport.java:585)
... 38 more
2010-11-11 13:50:30,261
但是，电子邮件仍会从列出的发件人发送给列出的收件人。所有其他事物（主题，身体等）都是空白的。如何在构建电子邮件时生成异常时停止发送电子邮件。
答案 0 :(得分：2)
有趣。似乎Sun的内部JavaMail实现容忍附件处理程序抛出的异常，并且无论如何都在继续。
我能想到的最简单的解决方案是对附件资源进行一些前期验证，例如
for (Entry<String, Resource> entry : inline.entrySet()) {
entry.getValue().getInputStream(); // validate the resource - fails if not existing
helper.addInline(entry.getKey(), entry.getValue());
}
这将热切地检查Resource是否可用。如果您愿意，也可以使用Resource.exists()来做这类事情。