用javamail 读邮件内容出现的异常：javax.mail.internet.ParseException

解析邮件的代码：
此方法返回的是邮件的内容
public static String getMailContent(Part part){
StringBuffer bodytext = new StringBuffer();
try{
String contenttype = part.getContentType();
int nameindex = contenttype.indexOf("name");
boolean conname =false;
if(nameindex != -1) conname=true;
System.out.println("CONTENTTYPE:　"+contenttype);
if(part.isMimeType("text/plain") && !conname){
bodytext.append((String)part.getContent());
}else if(part.isMimeType("text/html") && !conname){
bodytext.append((String)part.getContent());
}else if(contenttype.startsWith("multipart/alternative")){
Multipart multipart = (Multipart)part.getContent();
String p =getMailContent((Part)multipart.getBodyPart(1));
bodytext.append(p);
}
}catch(Exception ex){
ex.printStackTrace();
}
return bodytext.toString();
}


偶在解析带附件的邮件是，出现了此异常：

javax.mail.internet.ParseException
at javax.mail.internet.ParameterList.<init>(ParameterList.java:61)
at javax.mail.internet.ContentType.<init>(ContentType.java:83)
at javax.mail.internet.MimeMultipart.parse(MimeMultipart.java:269)
at javax.mail.internet.MimeMultipart.getBodyPart(MimeMultipart.java:172)
at Mail.MailManager.getMailContent(MailManager.java:303)