Google App Engine (GAE) message.getContent() using javamail and IMAP not works

问题

I have several days trying to get the contents of a message through IMAP on a Google App Engine Project.

I managed to extract all the other information, but to extract the contents of jumps me an error message (not work even invoking message.getContent.tostring(), I've tried as MultiPart).

I perform the same action from a normal project , (not GAE and using javamail.1.4.7), the content of the messages shown perfectly.

This is the code of GAE project:

    import java.util.Properties;
import java.util.logging.Logger;
import javax.mail.Session;
import java.io.IOException;
import javax.mail.Authenticator;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.PasswordAuthentication;
import javax.mail.Store;
import javax.servlet.http.*;

@SuppressWarnings("serial")
public class nuevo extends HttpServlet {

    private String User;
    private String Pass;

    private static final Logger log = Logger.getLogger(nuevo.class
            .getName());

    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {

        User = "User";
        Pass = "Pass";

        LlamaIMAP(resp);

    }

    public void LlamaIMAP(HttpServletResponse resp) {

        Properties props = System.getProperties();
        props.setProperty("mail.store.protocol", "imaps");
        props.put("mail.imap.host", "imap.gmail.com");
        props.put("mail.imap.user", User);
        props.put("mail.imap.socketFactory", 993);
        props.put("mail.imap.socketFactory.class",
                "javax.net.ssl.SSLSocketFactory");
        props.put("mail.imap.port", 993);
        Session session = Session.getDefaultInstance(props,
                new Authenticator() {
                    @Override
                    protected PasswordAuthentication getPasswordAuthentication() {
                        return new PasswordAuthentication(User, Pass);
                    }
                });
        try {
            Store store = session.getStore("imap");
            store.connect("imap.gmail.com", 993, User, Pass);
            Folder fldr = store.getFolder("Inbox");
            fldr.open(Folder.HOLDS_MESSAGES);
            // HOLDS_MESSAGES);
            Message[] ar = fldr.getMessages();
            int count = fldr.getMessageCount();
            resp.getWriter().println(count);
            resp.getWriter().println(ar[0].getAllRecipients()[0].toString());
            resp.getWriter().println(ar[0].getFrom()[0].toString());
            resp.getWriter().println(ar[0].getSentDate().toString());
            resp.getWriter().println(ar[0].getSubject());

            resp.getWriter().println(ar[0].getContent().toString());

        } catch (Exception exc) {
            try {
                resp.getWriter().println(exc + "error");
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }

    }
} 

回答1:

I managed to fix it.

Only you need to add this lines to the appengine-web.xml configuration file:

<class-loader-config>    
       <priority-specifier filename="imap.jar"/>   
       <priority-specifier filename="gimap.jar"/>    
       <priority-specifier filename="dsn.jar"/>    
       <priority-specifier filename="mailapi.jar"/>    
 </class-loader-config>

Thanks.

来源：https://stackoverflow.com/questions/17788697/google-app-engine-gae-message-getcontent-using-javamail-and-imap-not-works