Question

我在AWS Lambda上使用javax.mail包时遇到问题。

当尝试获取电子邮件的内容时，在本地运行时，getContent（）方法将返回MimeMultipart对象。在挂载到AWS lambda java8 docker映像时，它返回IMAPInputStream。

我已经看到了解决此问题的方法，包括在当前线程上设置类加载器，例如：Thread.currentThread().setContextClassLoader(this.class.getClassLoader());

但是，这对我不起作用。本地运行的类加载器与针对lambda java8 docker映像运行的类加载器不同。本地：sun.misc.Launcher$AppClassLoader 码头工人：java.net.URLClassLoader

我尝试像这样使用系统类加载器sun.misc.Launcher$AppClassLoader显式加载类：

Class c = java.lang.ClassLoader.getSystemClassLoader().loadClass("helpers.MailReader");
MailReader mail = (MailReader)c.newInstance();

这在本地运行时效果很好，但是再次对docker镜像失败：

java.lang.ClassNotFoundException: helpers.MailReader

因此，跨环境的系统类加载器有所不同。我对Java不太了解，似乎我只是缺少一些简单的东西并使它变得比实际更复杂。可能导致这种情况的环境有什么不同？

编辑：调试javax.activation.debug的输出：

MailcapCommandMap: load HOME
new MailcapFile: file /home/sbx_user1051/.mailcap
MailcapCommandMap: load SYS
new MailcapFile: file /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.141-1.b16.32.amzn1.x86_64/jre/lib/mailcap
MailcapCommandMap: load JAR
MailcapCommandMap: getResources
MailcapCommandMap: URL file:/var/task/META-INF/mailcap
new MailcapFile: InputStream
parse: text/plain;;     x-java-content-handler=com.sun.mail.handlers.text_plain
  Type: text/plain
    Command: content-handler, Class: com.sun.mail.handlers.text_plain
parse: text/html;;      x-java-content-handler=com.sun.mail.handlers.text_html
  Type: text/html
    Command: content-handler, Class: com.sun.mail.handlers.text_html
parse: text/xml;;       x-java-content-handler=com.sun.mail.handlers.text_xml
  Type: text/xml
    Command: content-handler, Class: com.sun.mail.handlers.text_xml
parse: multipart/*;;        x-java-content-handler=com.sun.mail.handlers.multipart_mixed; x-java-fallback-entry=true
  Type: multipart/*
    Command: content-handler, Class: com.sun.mail.handlers.multipart_mixed
parse: message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822
  Type: message/rfc822
    Command: content-handler, Class: com.sun.mail.handlers.message_rfc822
MailcapCommandMap: successfully loaded mailcap file from URL: file:/var/task/META-INF/mailcap
MailcapCommandMap: load DEF
new MailcapFile: InputStream
parse: image/gif;;      x-java-view=com.sun.activation.viewers.ImageViewer
  Type: image/gif
    Command: view, Class: com.sun.activation.viewers.ImageViewer
parse: image/jpeg;;     x-java-view=com.sun.activation.viewers.ImageViewer
  Type: image/jpeg
    Command: view, Class: com.sun.activation.viewers.ImageViewer
parse: text/*;;     x-java-view=com.sun.activation.viewers.TextViewer
  Type: text/*
    Command: view, Class: com.sun.activation.viewers.TextViewer
parse: text/*;;     x-java-edit=com.sun.activation.viewers.TextEditor
  Type: text/*
    Command: edit, Class: com.sun.activation.viewers.TextEditor
Merging commands for type text/*
MailcapCommandMap: successfully loaded mailcap file: /META-INF/mailcap.default
MailcapCommandMap: createDataContentHandler for multipart/alternative
  search DB #1
  search DB #2
  search fallback DB #1
    got content-handler
      class com.sun.mail.handlers.multipart_mixed
Can't load DCH com.sun.mail.handlers.multipart_mixed; Exception: java.lang.ClassNotFoundException: com/sun/mail/handlers/multipart_mixed
  search fallback DB #2

我在网上发现的与此相关的解决方案都没有帮助

AWS Lambda上的Java类加载不同吗？

0 个答案: