descargar archivos adjuntos de correo con Java

Question

Eché un vistazo al documento de referencia, y Spring parece tener un soporte bastante bueno para enviar correo. Sin embargo, necesito iniciar sesión en una cuenta de correo, leer los mensajes y descargar los archivos adjuntos. ¿La descarga de archivos adjuntos de correo es compatible con la API de correo de Spring?

Sé que puedes hacer esto con la API de Java Mail, pero en el pasado me ha parecido muy detallado y desagradable trabajar con él.

EDIT : he recibido varias respuestas que apuntan a tutoriales que describen cómo enviar correo con archivos adjuntos, pero lo que pregunto es cómo leer archivos adjuntos de recibido correo.

Saludos, Don

Answer 1

Aquí está la clase que uso para descargar correos electrónicos (con manejo de adjuntos). Tendrá que echar un vistazo a algunas de las cosas que está haciendo (como ignorar las clases de registro y las escrituras de la base de datos). También he cambiado el nombre de algunos de los paquetes para facilitar la lectura.

La idea general es que todos los archivos adjuntos se guardan como archivos individuales en el sistema de archivos, y cada correo electrónico se guarda como un registro en la base de datos con un conjunto de registros secundarios que apuntan a todas las rutas del archivo adjunto.

Concéntrese en el método doEMailDownload.

/**
  * Copyright (c) 2008 Steven M. Cherry
  * All rights reserved.
  */
package utils.scheduled;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.sql.Timestamp;
import java.util.Properties;
import java.util.Vector;

import javax.mail.Address;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.MimeBodyPart;

import glob.ActionLogicImplementation;
import glob.IOConn;
import glob.log.Log;
import logic.utils.sql.Settings;
import logic.utils.sqldo.EMail;
import logic.utils.sqldo.EMailAttach;

/**
  * This will connect to our incoming e-mail server and download any e-mails
  * that are found on the server.  The e-mails will be stored for further processing
  * in our internal database.  Attachments will be written out to separate files
  * and then referred to by the database entries.  This is intended to be  run by 
  * the scheduler every minute or so.
  *
  * @author Steven M. Cherry
  */
public class DownloadEMail implements ActionLogicImplementation {

    protected String receiving_host;
    protected String receiving_user;
    protected String receiving_pass;
    protected String receiving_protocol;
    protected boolean receiving_secure;
    protected String receiving_attachments;

    /** This will run our logic */
    public void ExecuteRequest(IOConn ioc) throws Exception {
        Log.Trace("Enter");

        Log.Debug("Executing DownloadEMail");
        ioc.initializeResponseDocument("DownloadEMail");

        // pick up our configuration from the server:
        receiving_host = Settings.getValue(ioc, "server.email.receiving.host");
        receiving_user = Settings.getValue(ioc, "server.email.receiving.username");
        receiving_pass = Settings.getValue(ioc, "server.email.receiving.password");
        receiving_protocol = Settings.getValue(ioc, "server.email.receiving.protocol");
        String tmp_secure = Settings.getValue(ioc, "server.email.receiving.secure");
        receiving_attachments = Settings.getValue(ioc, "server.email.receiving.attachments");

        // sanity check on the parameters:
        if(receiving_host == null || receiving_host.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no host defined.
        }
        if(receiving_user == null || receiving_user.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no user defined.
        }
        if(receiving_pass == null || receiving_pass.length() == 0){
            ioc.SendReturn();
            ioc.Close();
            Log.Trace("Exit");
            return; // no pass defined.
        }
        if(receiving_protocol == null || receiving_protocol.length() == 0){
            Log.Debug("EMail receiving protocol not defined, defaulting to POP");
            receiving_protocol = "POP";
        }
        if(tmp_secure == null || 
            tmp_secure.length() == 0 ||
            tmp_secure.compareToIgnoreCase("false") == 0 ||
            tmp_secure.compareToIgnoreCase("no") == 0
        ){
            receiving_secure = false;
        } else {
            receiving_secure = true;
        }
        if(receiving_attachments == null || receiving_attachments.length() == 0){
            Log.Debug("EMail receiving attachments not defined, defaulting to ./email/attachments/");
            receiving_attachments = "./email/attachments/";
        }

        // now do the real work.
        doEMailDownload(ioc);

        ioc.SendReturn();
        ioc.Close();
        Log.Trace("Exit");
    }

    protected void doEMailDownload(IOConn ioc) throws Exception {
        // Create empty properties
        Properties props = new Properties();
        // Get the session
        Session session = Session.getInstance(props, null);

        // Get the store
        Store store = session.getStore(receiving_protocol);
        store.connect(receiving_host, receiving_user, receiving_pass);

        // Get folder
        Folder folder = store.getFolder("INBOX");
        folder.open(Folder.READ_WRITE);

        try {

            // Get directory listing
            Message messages[] = folder.getMessages();

            for (int i=0; i < messages.length; i++) {
                // get the details of the message:
                EMail email = new EMail();
                email.fromaddr = messages[i].getFrom()[0].toString();
                Address[] to = messages[i].getRecipients(Message.RecipientType.TO);
                email.toaddr = "";
                for(int j = 0; j < to.length; j++){
                    email.toaddr += to[j].toString() + "; ";
                }
                Address[] cc;
                try {
                    cc = messages[i].getRecipients(Message.RecipientType.CC);
                } catch (Exception e){
                    Log.Warn("Exception retrieving CC addrs: %s", e.getLocalizedMessage());
                    cc = null;
                }
                email.cc = "";
                if(cc != null){
                    for(int j = 0; j < cc.length; j++){
                        email.cc += cc[j].toString() + "; ";
                    }
                }
                email.subject = messages[i].getSubject();
                if(messages[i].getReceivedDate() != null){
                    email.received_when = new Timestamp(messages[i].getReceivedDate().getTime());
                } else {
                    email.received_when = new Timestamp( (new java.util.Date()).getTime());
                }


                email.body = "";
                Vector<EMailAttach> vema = new Vector<EMailAttach>();
                Object content = messages[i].getContent();
                if(content instanceof java.lang.String){
                    email.body = (String)content;
                } else if(content instanceof Multipart){
                    Multipart mp = (Multipart)content;

                    for (int j=0; j < mp.getCount(); j++) {
                        Part part = mp.getBodyPart(j);

                        String disposition = part.getDisposition();

                        if (disposition == null) {
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart)part;
                            if (mbp.isMimeType("text/plain")) {
                                Log.Debug("Mime type is plain");
                                email.body += (String)mbp.getContent();
                            } else {
                                Log.Debug("Mime type is not plain");
                                // Special non-attachment cases here of 
                                // image/gif, text/html, ...
                                EMailAttach ema = new EMailAttach();
                                ema.name = decodeName(part.getFileName());
                                File savedir = new File(receiving_attachments);
                                savedir.mkdirs();
                                File savefile = File.createTempFile("emailattach", ".atch", savedir );
                                ema.path = savefile.getAbsolutePath();
                                ema.size = part.getSize();
                                vema.add(ema);
                                ema.size = saveFile(savefile, part);
                            }
                        } else if ((disposition != null) && 
                            (disposition.equals(Part.ATTACHMENT) || disposition.equals(Part.INLINE) ) 
                        ){
                            // Check if plain
                            MimeBodyPart mbp = (MimeBodyPart)part;
                            if (mbp.isMimeType("text/plain")) {
                                Log.Debug("Mime type is plain");
                                email.body += (String)mbp.getContent();
                            } else {
                                Log.Debug("Save file (%s)", part.getFileName() );
                                EMailAttach ema = new EMailAttach();
                                ema.name = decodeName(part.getFileName());
                                File savedir = new File(receiving_attachments);
                                savedir.mkdirs();
                                File savefile = File.createTempFile("emailattach", ".atch", savedir );
                                ema.path = savefile.getAbsolutePath();
                                ema.size = part.getSize();
                                vema.add(ema);
                                ema.size = saveFile( savefile, part);
                            }
                        }
                    }
                }

                // Insert everything into the database:
                logic.utils.sql.EMail.insertEMail(ioc, email);
                for(int j = 0; j < vema.size(); j++){
                    vema.get(j).emailid = email.id;
                    logic.utils.sql.EMail.insertEMailAttach(ioc, vema.get(j) );
                }

                // commit this message and all of it's attachments
                ioc.getDBConnection().commit();

                // Finally delete the message from the server.
                messages[i].setFlag(Flags.Flag.DELETED, true);
            }

            // Close connection 
            folder.close(true); // true tells the mail server to expunge deleted messages.
            store.close();
        } catch (Exception e){
            folder.close(true); // true tells the mail server to expunge deleted messages.
            store.close();
            throw e;
        }

    }

    protected int saveFile(File saveFile, Part part) throws Exception {

        BufferedOutputStream bos = new BufferedOutputStream( new FileOutputStream(saveFile) );

        byte[] buff = new byte[2048];
        InputStream is = part.getInputStream();
        int ret = 0, count = 0;
        while( (ret = is.read(buff)) > 0 ){
            bos.write(buff, 0, ret);
            count += ret;
        }
        bos.close();
        is.close();
        return count;
    }

    protected String decodeName( String name ) throws Exception {
        if(name == null || name.length() == 0){
            return "unknown";
        }
        String ret = java.net.URLDecoder.decode( name, "UTF-8" );

        // also check for a few other things in the string:
        ret = ret.replaceAll("=\\?utf-8\\?q\\?", "");
        ret = ret.replaceAll("\\?=", "");
        ret = ret.replaceAll("=20", " ");

        return ret;
    }

}

Answer 2

Trabajé un poco el ejemplo de Steven y eliminé las partes del código específico de Steven. Mi código no leerá el cuerpo de un correo electrónico si tiene archivos adjuntos. Eso está bien para mi caso, pero es posible que desee refinarlo más para el suyo.

package utils;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Properties;

import javax.mail.Address;
import javax.mail.Flags;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.Multipart;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.MimeBodyPart;

public class IncomingMail {

 public static List<Email> downloadPop3(String host, String user, String pass, String downloadDir) throws Exception {

  List<Email> emails = new ArrayList<Email>();

  // Create empty properties
  Properties props = new Properties();

  // Get the session
  Session session = Session.getInstance(props, null);

  // Get the store
  Store store = session.getStore("pop3");
  store.connect(host, user, pass);

  // Get folder
  Folder folder = store.getFolder("INBOX");
  folder.open(Folder.READ_WRITE);

  try {
   // Get directory listing
   Message messages[] = folder.getMessages();
   for (int i = 0; i < messages.length; i++) {

    Email email = new Email();

    // from 
    email.from = messages[i].getFrom()[0].toString();

    // to list
    Address[] toArray = messages[i] .getRecipients(Message.RecipientType.TO);
    for (Address to : toArray) { email.to.add(to.toString()); }

    // cc list
    Address[] ccArray = null;
    try {
     ccArray = messages[i] .getRecipients(Message.RecipientType.CC);
    } catch (Exception e) { ccArray = null; }
    if (ccArray != null) {
     for (Address c : ccArray) {
      email.cc.add(c.toString());
     }
    }

    // subject
    email.subject = messages[i].getSubject();

    // received date
    if (messages[i].getReceivedDate() != null) {
     email.received = messages[i].getReceivedDate();
    } else {
     email.received = new Date();
    }

    // body and attachments
    email.body = "";
    Object content = messages[i].getContent();
    if (content instanceof java.lang.String) {

     email.body = (String) content;

    } else if (content instanceof Multipart) {

     Multipart mp = (Multipart) content;

     for (int j = 0; j < mp.getCount(); j++) {

      Part part = mp.getBodyPart(j);
      String disposition = part.getDisposition();

      if (disposition == null) {

       MimeBodyPart mbp = (MimeBodyPart) part;
       if (mbp.isMimeType("text/plain")) {
        // Plain
        email.body += (String) mbp.getContent();
       } 

      } else if ((disposition != null) && (disposition.equals(Part.ATTACHMENT) || disposition .equals(Part.INLINE))) {

       // Check if plain
       MimeBodyPart mbp = (MimeBodyPart) part;
       if (mbp.isMimeType("text/plain")) {
        email.body += (String) mbp.getContent();
       } else {
        EmailAttachment attachment = new EmailAttachment();
        attachment.name = decodeName(part.getFileName());
        File savedir = new File(downloadDir);
        savedir.mkdirs();
        // File savefile = File.createTempFile( "emailattach", ".atch", savedir);
        File savefile = new File(downloadDir,attachment.name);
        attachment.path = savefile.getAbsolutePath();
        attachment.size = saveFile(savefile, part);
        email.attachments.add(attachment);
       }
      }
     } // end of multipart for loop 
    } // end messages for loop

    emails.add(email);

    // Finally delete the message from the server.
    messages[i].setFlag(Flags.Flag.DELETED, true);
   }

   // Close connection
   folder.close(true); // true tells the mail server to expunge deleted messages
   store.close();

  } catch (Exception e) {
   folder.close(true); // true tells the mail server to expunge deleted
   store.close();
   throw e;
  }

  return emails;
 }

 private static String decodeName(String name) throws Exception {
  if (name == null || name.length() == 0) {
   return "unknown";
  }
  String ret = java.net.URLDecoder.decode(name, "UTF-8");

  // also check for a few other things in the string:
  ret = ret.replaceAll("=\\?utf-8\\?q\\?", "");
  ret = ret.replaceAll("\\?=", "");
  ret = ret.replaceAll("=20", " ");

  return ret;
 }

 private static int saveFile(File saveFile, Part part) throws Exception {

  BufferedOutputStream bos = new BufferedOutputStream(
    new FileOutputStream(saveFile));

  byte[] buff = new byte[2048];
  InputStream is = part.getInputStream();
  int ret = 0, count = 0;
  while ((ret = is.read(buff)) > 0) {
   bos.write(buff, 0, ret);
   count += ret;
  }
  bos.close();
  is.close();
  return count;
 }

}

También necesitas estas dos clases de ayuda

package utils;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

public class Email {

 public Date received;
 public String from;
 public List<String> to = new ArrayList<String>();
 public List<String> cc = new ArrayList<String>();
 public String subject;
 public String body;
 public List<EmailAttachment> attachments = new ArrayList<EmailAttachment>();
}

y

package utils;

public class EmailAttachment {

 public String name;
 public String path;
 public int size;
}

Utilicé esto para probar las clases anteriores

package utils;

import java.util.List;


public class Test {

 public static void main(String[] args) {

  String host = "some host";
  String user = "some user";
  String pass = "some pass";
  String downloadDir = "/Temp";
  try {
   List<Email> emails = IncomingMail.downloadPop3(host, user, pass, downloadDir);
   for ( Email email : emails ) {
    System.out.println(email.from);
    System.out.println(email.subject);
    System.out.println(email.body);
    List<EmailAttachment> attachments = email.attachments;
    for ( EmailAttachment attachment : attachments ) {
     System.out.println(attachment.path+" "+attachment.name);
    }
   }
  } catch (Exception e) { e.printStackTrace(); }

 }

}

Puede encontrar más información en http://java.sun.com/ developer / onlineTraining / JavaMail / contents.html

Answer 3

Aquí hay un error:

else if ((disposition != null) && (disposition.equals(Part.ATTACHMENT)
 || disposition.equals(Part.INLINE) ) 

debería ser:

else if ((disposition.equalsIgnoreCase(Part.ATTACHMENT)
 || disposition.equalsIgnoreCase(Part.INLINE))

Gracias a @Stevenmcherry por tu respuesta

Answer 4

Usé el correo de Apache Commons para esta tarea:

import java.util.List;
import javax.activation.DataSource; 
import javax.mail.internet.MimeMessage;   
import org.apache.commons.mail.util.MimeMessageParser;   

public List<DataSource> getAttachmentList(MimeMessage message) throws Exception {
    msgParser = new MimeMessageParser(message);
    msgParser.parse();
    return msgParser.getAttachmentList();
}

Desde un objeto DataSource puede recuperar un InputStream (al lado del nombre y tipo) del archivo adjunto (ver API: http://docs.oracle.com/javase/6/docs/api/ javax /ctivation / DataSource.html? is-external = true ).

Answer 5

Hasta ahora, solo he usado las API de JavaMail (y he estado razonablemente feliz con ellas para mis propósitos). Si el paquete completo de JavaMail es demasiado pesado para usted, el motor de transporte subyacente se puede usar sin las capas superiores del paquete. Cuanto más bajo vayas en las pilas SMTP, POP3 e IMAP, más tienes que estar preparado para hacer por ti mismo.

En el lado positivo, también podrás ignorar las partes que no son necesarias para tu aplicación.

Answer 6

import java.io.IOException;
import java.io.InputStream;

import javax.mail.internet.MimeMessage;
import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.InputStreamSource;
import org.springframework.mail.javamail.JavaMailSender;
import org.springframework.mail.javamail.MimeMessageHelper;
import org.springframework.mail.javamail.MimeMessagePreparator;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.commons.CommonsMultipartFile;

@Controller
@RequestMapping("/sendEmail.do")
public class SendEmailAttachController {
    @Autowired
    private JavaMailSender mailSender;

    @RequestMapping(method = RequestMethod.POST)
    public String sendEmail(HttpServletRequest request,
            final @RequestParam CommonsMultipartFile attachFile) {

        // Input here
        final String emailTo = request.getParameter("mailTo");
        final String subject = request.getParameter("subject");
        final String yourmailid = request.getParameter("yourmail");
        final String message = request.getParameter("message");

        // Logging
        System.out.println("emailTo: " + emailTo);
        System.out.println("subject: " + subject);
        System.out.println("Your mail id is: "+yourmailid);
        System.out.println("message: " + message);
        System.out.println("attachFile: " + attachFile.getOriginalFilename());

        mailSender.send(new MimeMessagePreparator() {

            @Override
            public void prepare(MimeMessage mimeMessage) throws Exception {
                MimeMessageHelper messageHelper = new MimeMessageHelper(
                        mimeMessage, true, "UTF-8");
                messageHelper.setTo(emailTo);
                messageHelper.setSubject(subject);
                messageHelper.setReplyTo(yourmailid);
                messageHelper.setText(message);

                // Attachment with mail
                String attachName = attachFile.getOriginalFilename();
                if (!attachFile.equals("")) {

                    messageHelper.addAttachment(attachName, new InputStreamSource() {

                        @Override
                        public InputStream getInputStream() throws IOException {
                            return attachFile.getInputStream();
                        }
                    });
                }

            }

        });

        return "Result";
    }
}