Question

我不知道为什么在从邮件服务器读取带有附件文件的邮件时出现以下异常：

Exception in thread "main" javax.mail.MessagingException: Missing start boundary

        at javax.mail.internet.MimeMultipart.parsebm<MimeMultipart.java:872)
        at javax.mail.internet.MimeMultipart.parse<MimeMultipart.java:493)
        at javax.mail.internet.MimeMultipart.getCount<MimeMultipart.java:240)
        at GetParts.handleMultipart(GetParts.java:57)
        at GetParts.main(GetParts.java:42)

我用来阅读这些消息的文件是：

import java.io.*;
import java.util.Properties;
import javax.mail.*;
import javax.mail.internet.*;

public class GetParts {
  public static void main (String args[]) 
      throws Exception {
    String host = args[0];
    String username = args[1];
    String password = args[2];

    // Get session
    Properties props=new Properties();
    props.put("mail.mime.multipart.ignoremissingboundaryparamete",true);
    Session session = Session.getInstance(
      props, null);
ContentType ct=new ContentType();
    // Get the store
    Store store = session.getStore("pop3");
    store.connect(host, username, password);

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

    BufferedReader reader = new BufferedReader (
      new InputStreamReader(System.in));

    // Get directory
    Message message[] = folder.getMessages();
    for (int i=0, n=message.length; i<n; i++) {
       System.out.println(i + ": "
         + message[i].getFrom()[0] 
         + "\t" + message[i].getSubject());
          //message[i].setHeader("Content-Type","multipart/mixed");
      System.out.println("Do you want to get the content? [YES to read/QUIT to end]");
      String line = reader.readLine();
      if ("YES".equals(line)) {
        Object content = message[i].getContent();
        if (content instanceof Multipart) {
          handleMultipart((Multipart)content);
        } else {
          handlePart(message[i]);
        }
      } else if ("QUIT".equals(line)) {
        break;
      }
    }

    // Close connection 
    folder.close(false);
    store.close();
  }
  public static void handleMultipart(Multipart multipart) 
      throws MessagingException, IOException {
      System.out.println(multipart.getCount());
    for (int i=0, n=multipart.getCount(); i<n; i++) {
      handlePart(multipart.getBodyPart(i));
    }
  }
  public static void handlePart(Part part) 
      throws MessagingException, IOException {
    String disposition = part.getDisposition();
    System.out.println("Disposition "+disposition);
    String contentType = part.getContentType();
    System.out.println("contentType "+contentType);
    if (disposition == null) { // When just body
      System.out.println("Null: "  + contentType);
      // Check if plain
      if ((contentType.length() >= 10) && 
          (contentType.toLowerCase().substring(
           0, 10).equals("text/plain"))) {
        part.writeTo(System.out);
      } else { // Don't think this will happen
        System.out.println("Other body: " + contentType);
        part.writeTo(System.out);
      }
    } else if (disposition.equalsIgnoreCase(Part.ATTACHMENT)) {
      System.out.println("Attachment: " + part.getFileName() + 
        " : " + contentType);
      saveFile(part.getFileName(), part.getInputStream());
    } else if (disposition.equalsIgnoreCase(Part.INLINE)) {
      System.out.println("Inline: " + 
        part.getFileName() + 
        " : " + contentType);
      saveFile(part.getFileName(), part.getInputStream());
    } else {  // Should never happen
      System.out.println("Other: " + disposition);
    }
  }
  public static void saveFile(String filename,
      InputStream input) throws IOException {
    if (filename == null) {
      filename = File.createTempFile("xx", ".out").getName();
    }
    // Do no overwrite existing file
    File file = new File(filename);
    for (int i=0; file.exists(); i++) {
      file = new File(filename+i);
    }
    FileOutputStream fos = new FileOutputStream(file);
    BufferedOutputStream bos = new BufferedOutputStream(fos);

    BufferedInputStream bis = new BufferedInputStream(input);
    int aByte;
    while ((aByte = bis.read()) != -1) {
      bos.write(aByte);
    }
    bos.flush();
    bos.close();
    bis.close();
  }
}

Answer 1

我刚遇到同样的问题。边界在Multipart Content-Type中指定。您可以在此source中找到更多信息。您还可以使用getContentType()功能查看当前消息之一。在我的情况下，我得到了这个结果：

multipart/mixed; boundary=--boundary_25_2d74d02b-d0d6-4f28-a311-4d1b7d107417

因此getCount()函数使用此边界来分隔组成多个部分的所有部分。看起来可能存在此边界被破坏的情况。

mail.mime.multipart.ignoreexistingboundaryparameter System属性可以设置为true以使任何边界被忽略，而是像mail.mime.multipart.ignoremissingboundaryparameter一样在消息中搜索边界线。

我遵循了这些说明，一切正常。我添加了以下代码：

System.setProperty("mail.mime.multipart.ignoreexistingboundaryparameter", "true");

希望它有所帮助！

Answer 2

尝试在multipartEntityBuilder上设置模式例如： multipartEntityBuilder.setMode（HttpMultipartMode.RFC6532）;

使用附件文件读取消息时缺少启动边界异常

2 个答案: