java.lang.ClassCastException：java.lang.String不能转换为javax.mail.Multipart [英] java.lang.ClassCastException: java.lang.String cannot be cast to javax.mail.Multipart

问题描述

这是我从java教程中获取的代码，但是当我尝试接收从计算机发送的正常消息，而不是通过GMail发送时，我的问题出现了。如果我通过GMail收到电子邮件，它运行正常并返回邮件，但是尝试从常规桌面邮件客户端检索邮件返回

This is my code below taken from a java tutorial - however my issue comes in when I try and recieve a normal message sent from a computer, as opposed to sent through GMail. If I recieve the email through GMail it runs fine and returns the mail, however trying to retrieve a mail from a conventional desktop mail client returns

错误：

java.lang.ClassCastException: java.lang.String cannot be cast to javax.mail.Multipart
at gridnotifierproject_pcbuild.HandleMailInput.retrieveOneMail(HandleMailInput.java:37)
at gridnotifierproject_pcbuild.GridNotifierProject_PCBuild.main(GridNotifierProject_PCBuild.java:22)

代码：

Properties props = new Properties();
    props.setProperty("mail.store.protocol", "imaps");
    try {   
        Session session = Session.getInstance(props, null);
        Store store = session.getStore();
        store.connect("imap.gmail.com", "***********@gmail.com", "******");
        System.out.println("Established Connection to Server!");
        Folder inbox = store.getFolder("Inbox");
        inbox.open(Folder.READ_ONLY);
        Message msg = inbox.getMessage(inbox.getMessageCount());
        System.out.println("Found specified Folder, retrieving the latest message...");
        Address[] in = msg.getFrom();
        for (Address address : in) {
            System.out.println("FROM:" + address.toString());
        }
        Multipart mp = (Multipart) msg.getContent();
        BodyPart bp = mp.getBodyPart(0);
        System.out.println("SENT DATE:" + msg.getSentDate());
        System.out.println("SUBJECT:" + msg.getSubject());
        System.out.println("CONTENT:" + bp.getContent());
    } catch (Exception mex) {
        mex.printStackTrace();
    }

推荐答案

！

您的消息内容返回String，您正在尝试键入转换为Multipart。

Your message content returning String and you are trying to type cast to Multipart.

Object content = msg.getContent();  
if (content instanceof String)  
{  
    String body = (String)content;  
    ...  
}  
else if (content instanceof Multipart)  
{  
    Multipart mp = (Multipart)content;  
    ...  
}  

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