早上好，
我已经在这个项目上工作了几天，并且已经停止了。下载附件似乎需要永远，它似乎是在磁盘行的写入文件。我已经阅读了很多选项（FileChannel，批量getContent和其他一些但不能使这个代码以合理的速率执行）我不确定是否唯一的瓶颈是从O365下载文件然而我想我会问一个问题，看看是否有人可以查看这段代码并希望告诉我我做错了什么。该应用程序的目标是登录Exchange Online（o365）并下载某个邮箱中的所有附件。请注意，此代码已被修改了很多次，以确定我是否可以通过使用线程等来提高性能：
正如我所说，我已经将所有内容转移到了很多地方，试图让这项工作更好，所以请不要因为某些代码没有太多意义而让我感到厌烦。我不想让其他人完成这个项目，我正在寻找一种我没有很多经验的语言的指导。
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 = "XXX@XXX.com";
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();
}
}
编辑：
props.put("mail.imaps.fetchsize", "819200");
props.put("mail.imaps.partialfetch", "false");
加速，128秒到12秒下载7mb文件。
答案 0 :(得分：2)
JavaMail属性在每个协议提供程序的页面上的javadocs中描述。例如，com.sun.mail.imap package javadoc page上描述了IMAP提供程序属性。