使用Java在郵件中附加文檔

Question

我正在嘗試使用Java將文檔文件附加到郵件中。 要附加的文檔要通過瀏覽按鈕從用戶中選擇。

我嘗試了下面的編碼..

<form action="emailservlet" enctype="multipart/form-data">
  Profile  :  <input type="file" name="filename"/><br/>     
    <input type="submit" value="submit">            
</form>

並在servlet中

      File path=new File(fil);
      fil=path.getAbsolutePath();
      messageBodyPart = new MimeBodyPart();
      DataSource source = new FileDataSource(fil);
      messageBodyPart.setDataHandler(new DataHandler(source));
      messageBodyPart.setFileName(fil);
      multipart.addBodyPart(messageBodyPart);

但是拋出了filenotfound異常，請幫助我糾正此問題...

提前致謝...

Answer 1

您可以按照以下方式進行操作：

messageBodyPart.setText("This is message body");
messageBodyPart = new MimeBodyPart();
String filename = "/home/file.txt";
DataSource source = new FileDataSource(filename);
messageBodyPart.setDataHandler(new DataHandler(source));
messageBodyPart.setFileName(filename);
multipart.addBodyPart(messageBodyPart);
message.setContent(multipart);

然后使用以下傳輸對象發送消息：

Transport.send(message);

而且，您需要做的就是更新文件路徑，因為從客戶端發送文件時，您可以根據您使用的技術servlet / struts2直接映射它。

Answer 2

當您將servlet用作服務器端技術時，以下將是使用servlet發送帶有文件附件的電子郵件的完整示例。

1.）創建以下名稱為EmailUtility.java的 Java類

import java.io.File;
import java.io.IOException;
import java.util.Date;
import java.util.List;
import java.util.Properties;

import javax.mail.Authenticator;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

/**
 * A utility class for sending e-mail message with attachment.
 * @author www.codejava.net
 *
 */
public class EmailUtility {

    /**
     * Sends an e-mail message from a SMTP host with a list of attached files.
     *
     */
    public static void sendEmailWithAttachment(String host, String port,
            final String userName, final String password, String toAddress,
            String subject, String message, List<File> attachedFiles)
                    throws AddressException, MessagingException {
        // sets SMTP server properties
        Properties properties = new Properties();
        properties.put("mail.smtp.host", host);
        properties.put("mail.smtp.port", port);
        properties.put("mail.smtp.auth", "true");
        properties.put("mail.smtp.starttls.enable", "true");
        properties.put("mail.user", userName);
        properties.put("mail.password", password);

        // creates a new session with an authenticator
        Authenticator auth = new Authenticator() {
            public PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(userName, password);
            }
        };
        Session session = Session.getInstance(properties, auth);

        // creates a new e-mail message
        Message msg = new MimeMessage(session);

        msg.setFrom(new InternetAddress(userName));
        InternetAddress[] toAddresses = { new InternetAddress(toAddress) };
        msg.setRecipients(Message.RecipientType.TO, toAddresses);
        msg.setSubject(subject);
        msg.setSentDate(new Date());

        // creates message part
        MimeBodyPart messageBodyPart = new MimeBodyPart();
        messageBodyPart.setContent(message, "text/html");

        // creates multi-part
        Multipart multipart = new MimeMultipart();
        multipart.addBodyPart(messageBodyPart);

        // adds attachments
        if (attachedFiles != null && attachedFiles.size() > 0) {
            for (File aFile : attachedFiles) {
                MimeBodyPart attachPart = new MimeBodyPart();

                try {
                    attachPart.attachFile(aFile);
                } catch (IOException ex) {
                    ex.printStackTrace();
                }

                multipart.addBodyPart(attachPart);
            }
        }

        // sets the multi-part as e-mail's content
        msg.setContent(multipart);

        // sends the e-mail
        Transport.send(msg);
    }
}

2.）在您的jsp頁面中創建以下表單

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
    "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Send an e-mail with attachment</title>
</head>
<body>
    <form action="SendMailAttachServlet" method="post" enctype="multipart/form-data">
        <table border="0" width="60%" align="center">
            <caption><h2>Send New E-mail</h2></caption>
            <tr>
                <td width="50%">Recipient address </td>
                <td><input type="text" name="recipient" size="50"/></td>
            </tr>
            <tr>
                <td>Subject </td>
                <td><input type="text" name="subject" size="50"/></td>
            </tr>
            <tr>
                <td>Content </td>
                <td><textarea rows="10" cols="39" name="content"></textarea> </td>
            </tr>
            <tr>
                <td>Attach file </td>
                <td><input type="file" name="file" size="50" /></td>
            </tr>
            <tr>
                <td colspan="2" align="center"><input type="submit" value="Send"/></td>
            </tr>
        </table> 
    </form>
</body>
</html>

請注意，標記必須具有屬性enctype =“ multipart / form-data ”。 如果我們想要更多的附件，我們可以復制標簽。

3.）創建以下名稱為SendMailAttachServlet的 Servlet類

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.MultipartConfig;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.Part;

/**
 * A servlet that takes message details from user and send it as a new e-mail
 * through an SMTP server. The e-mail message may contain attachments which
 * are the files uploaded from client.
 *
 * @author www.codejava.net
 *
 */
@WebServlet("/SendMailAttachServlet")
@MultipartConfig(fileSizeThreshold = 1024 * 1024 * 2,   // 2MB
                maxFileSize = 1024 * 1024 * 10,         // 10MB
                maxRequestSize = 1024 * 1024 * 50)      // 50MB
public class SendMailAttachServlet extends HttpServlet {
    private String host;
    private String port;
    private String user;
    private String pass;

    public void init() {
        // reads SMTP server setting from web.xml file
        ServletContext context = getServletContext();
        host = context.getInitParameter("host");
        port = context.getInitParameter("port");
        user = context.getInitParameter("user");
        pass = context.getInitParameter("pass");
    }

    /**
     * handles form submission
     */
    protected void doPost(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        List<File> uploadedFiles = saveUploadedFiles(request);

        String recipient = request.getParameter("recipient");
        String subject = request.getParameter("subject");
        String content = request.getParameter("content");

        String resultMessage = "";

        try {
            EmailUtility.sendEmailWithAttachment(host, port, user, pass,
                    recipient, subject, content, uploadedFiles);

            resultMessage = "The e-mail was sent successfully";
        } catch (Exception ex) {
            ex.printStackTrace();
            resultMessage = "There were an error: " + ex.getMessage();
        } finally {
            deleteUploadFiles(uploadedFiles);
            request.setAttribute("message", resultMessage);
            getServletContext().getRequestDispatcher("/Result.jsp").forward(
                    request, response);
        }
    }

    /**
     * Saves files uploaded from the client and return a list of these files
     * which will be attached to the e-mail message.
     */
    private List<File> saveUploadedFiles(HttpServletRequest request)
            throws IllegalStateException, IOException, ServletException {
        List<File> listFiles = new ArrayList<File>();
        byte[] buffer = new byte[4096];
        int bytesRead = -1;
        Collection<Part> multiparts = request.getParts();
        if (multiparts.size() > 0) {
            for (Part part : request.getParts()) {
                // creates a file to be saved
                String fileName = extractFileName(part);
                if (fileName == null || fileName.equals("")) {
                    // not attachment part, continue
                    continue;
                }

                File saveFile = new File(fileName);
                System.out.println("saveFile: " + saveFile.getAbsolutePath());
                FileOutputStream outputStream = new FileOutputStream(saveFile);

                // saves uploaded file
                InputStream inputStream = part.getInputStream();
                while ((bytesRead = inputStream.read(buffer)) != -1) {
                    outputStream.write(buffer, 0, bytesRead);
                }
                outputStream.close();
                inputStream.close();

                listFiles.add(saveFile);
            }
        }
        return listFiles;
    }

    /**
     * Retrieves file name of a upload part from its HTTP header
     */
    private String extractFileName(Part part) {
        String contentDisp = part.getHeader("content-disposition");
        String[] items = contentDisp.split(";");
        for (String s : items) {
            if (s.trim().startsWith("filename")) {
                return s.substring(s.indexOf("=") + 2, s.length() - 1);
            }
        }
        return null;
    }

    /**
     * Deletes all uploaded files, should be called after the e-mail was sent.
     */
    private void deleteUploadFiles(List<File> listFiles) {
        if (listFiles != null && listFiles.size() > 0) {
            for (File aFile : listFiles) {
                aFile.delete();
            }
        }
    }
}

4.）使用web.xml配置來配置SMTP服務器

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>EmailAttachWebApp</display-name>

    <!-- SMTP settings -->
    <context-param>
        <param-name>host</param-name>
        <param-value>smtp.gmail.com</param-value>
    </context-param>

    <context-param>
        <param-name>port</param-name>
        <param-value>25</param-value>
    </context-param>

    <context-param>
        <param-name>port</param-name>
        <param-value>587</param-value>
    </context-param>

    <context-param>
        <param-name>user</param-name>
        <param-value>YOUR_EMAIL</param-value>
    </context-param>

    <context-param>
        <param-name>pass</param-name>
        <param-value>YOUR_PASS</param-value>
    </context-param>

    <welcome-file-list>
        <welcome-file>EmailForm.jsp</welcome-file>
    </welcome-file-list>
</web-app>

希望對您有幫助！！