这是我用于下载电子邮件（带有附件处理）的类。您必须浏览一下它正在做的一些事情（例如忽略日志记录类和数据库写操作）。为了方便阅读，我还对一些软件包进行了重命名。
通常的想法是，所有附件都保存为文件系统中的单个文件，每封电子邮件都保存为数据库中的记录，其中包含一组指向所有附件文件路径的子记录。
专注于doEMailDownload方法。
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;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; 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 = depreName(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 = depreName(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 depreName( String name ) throws Exception { if(name == null || name.length() == 0){ return "unknown"; } String ret = java.net.URLDeprer.depre( 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; }}
