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早上好，使用Javamail獲取附件
我一直在這個項目上工作了幾天，現在已經停止了。下載附件似乎需要永久，它似乎在寫入文件到磁盤行。我已經閱讀了很多選項（FileChannel，bulk getContent和其他一些選項，但不能讓代碼以合理的速度執行）我不確定是否唯一的瓶頸是從O365下載文件，但我認爲我會問一個問題，看看有人可以查看這段代碼，並希望告訴我我做錯了什麼。該應用程序的目標是登錄到Exchange Online（o365）並下載某個郵箱中的所有附件。請注意，此代碼已被多次修改，以查看是否可以通過使用線程等來提高性能：
正如我所說的，我已將所有內容都轉移到了很多方面，以便使此工作更好，因此請不要對於一些沒有太多意義的代碼，我不會讓我失望。我不想讓別人來完成這個項目，我正在尋找一種我沒有很多經驗的語言的指導。
package o365connect;
import java.io.IOException;
import java.net.UnknownHostException;
import java.util.Properties;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.NoSuchProviderException;
import javax.mail.Part;
import javax.mail.Session;
import javax.mail.Store;
import javax.mail.internet.MimeBodyPart;
/**
*
* @author Charlie
*/
public class AttDownload extends Thread {
public static int Lower = 0;
public static int Upper = 0;
public static int Counter = 0;
public static Session session;
public static Store store;
public static Properties props = new Properties();
public static boolean fTest = false;
AttDownload(int i, int ii) {
Lower = i;
Upper = ii;
}
AttDownload() throws UnknownHostException {
super();
}
@Override
public void run() {
String SSL_FACTORY = "javax.net.ssl.SSLSocketFactory";
String pop3Host = "outlook.office365.com";
String mailStoreType = "imap";
String path = "Inbox/Scans to file";
String userName = "[email protected]";
String password = "XXXXXXX";
Folder emailFolder;
try {
props.setProperty("mail.imaps.socketFactory.class", SSL_FACTORY);
props.setProperty("mail.imaps.socketFactory.fallback", "false");
props.setProperty("mail.imaps.port", "993");
props.setProperty("mail.imaps.socketFactory.port", "993");
props.put("mail.imaps.host", "outlook.office365.com");
session = Session.getInstance(props);
int Size = functions.MBSize(pop3Host, userName, password, path);
System.out.println(Size);
store = session.getStore("imaps");
store.connect(pop3Host, userName, password);
emailFolder = store.getFolder(path);
emailFolder.open(Folder.READ_ONLY);
try {
Message[] messages;
messages = emailFolder.getMessages(Lower, Upper);
System.out.println("starting thread for - " + Lower + " - " + Upper);
int ASuc = receiveEmail(messages);
} catch (MessagingException | IOException ex) {
Logger.getLogger(AttDownload.class.getName()).log(Level.SEVERE, null, ex);
}
} catch (NoSuchProviderException ex) {
Logger.getLogger(AttDownload.class.getName()).log(Level.SEVERE, null, ex);
} catch (MessagingException ex) {
Logger.getLogger(AttDownload.class.getName()).log(Level.SEVERE, null, ex);
}
}
public static int receiveEmail(Message messagesarr[]) throws IOException, MessagingException {
for (Message messagesarr1 : messagesarr) {
try {
Message message = messagesarr1;
Object content = message.getContent();
if (content instanceof String) {
} else if (content instanceof Multipart) {
Multipart multipart = (Multipart) message.getContent();
for (int k = 0; k < multipart.getCount(); k++) {
MimeBodyPart bodyPart = (MimeBodyPart) multipart.getBodyPart(k);
if (Part.ATTACHMENT.equalsIgnoreCase(bodyPart.getDisposition())) {
long startTime = System.currentTimeMillis();
int ran = (int) startTime;
String fileName;
String fName = bodyPart.getFileName();
if (fName != null && !fName.isEmpty()) {
fileName = fName.replaceAll("\\s+", "");
} else {
continue;
}
if ("ATT00001.txt".equals(fileName)) {
continue;
} else {
System.out.println("starting copy of - " + fileName);
}
String destFilePath = "D:/Scans/";
bodyPart.saveFile(destFilePath + bodyPart.getFileName());
long stopTime = System.currentTimeMillis();
System.out.println("finished copying of - " + fileName + " - " + (stopTime - startTime) + " miliseconds.");
System.out.println(Counter);
Counter++;
} else {
}
}
}
}catch (MessagingException e) {
System.out.println(e);
}
}
return 1;
}
}
Functions.java
package o365connect;
import javax.mail.Folder;
import javax.mail.MessagingException;
import javax.mail.NoSuchProviderException;
import javax.mail.Session;
import javax.mail.Store;
import static o365connect.AttDownload.store;
/**
*
* @author Oliver
*/
public class functions {
public static int TestUser(String pop3host, String Username, String Password) throws NoSuchProviderException, MessagingException {
try {
Session session = Session.getInstance(AttDownload.props);
store = session.getStore("imaps");
store.connect(pop3host, Username, Password);
return 0;
} catch (MessagingException e) {
System.out.println(e + "User Name Invalid");
return 1;
}
}
public static Folder TestFolder(Store store, String Path) throws MessagingException {
Folder emailFolder;
emailFolder = store.getFolder(Path);
emailFolder.open(Folder.READ_ONLY);
AttDownload.fTest = true;
emailFolder.close(false);
return emailFolder;
}
public static int MBSize(String pop3Host, String userName, String password, String Path) {
int Size = 0;
Session session = Session.getInstance(AttDownload.props);
try {
Store store = session.getStore("imaps");
store.connect(pop3Host, userName, password);
Folder emailFolder = store.getFolder(Path);
emailFolder.open(Folder.READ_ONLY);
Size = emailFolder.getMessageCount();
emailFolder.close(false);
store.close();
return Size;
} catch (MessagingException e) {
System.out.println(e + "MBSize");
}
return Size;
}
}
O365Connect.java
package o365connect;
import java.io.IOException;
import javax.mail.MessagingException;
public class O365Connect {
public static void main(String[] args) throws IOException, MessagingException, InterruptedException {
MainScreen ms = new MainScreen();
ms.setVisible(true);
AttDownload dl = new AttDownload(1, 1000);
dl.start();
}
}
編輯：
props.put("mail.imaps.fetchsize", "819200");
props.put("mail.imaps.partialfetch", "false");
加快事情了128秒降低到12秒下載7MB文件。
如果partialfetch爲false，則不使用fetchsize;它會在一個請求中下載整個附件。只要你有足夠的內存以獲得最大的可能附件，那就沒問題。否則，請將partialfetch設置爲true（默認值），並將fetchsize設置得足夠大，以便在不使用過多內存的情況下提供合理的性能。 –
你可以把它作爲一個答案，因爲這解釋了我似乎無法找到的一切，因爲我不知道這兩個屬性存在。 – Charlie
完成。你在哪裏尋找有關JavaMail屬性的文檔？你看過javadoc，但沒有找到屬性？你甚至不知道javadoc？你看過[JavaMail FAQ]（http://www.oracle.com/technetwork/java/javamail/faq/index.html）嗎？ –