SendGrid电子邮件API，发送电子邮件附件

Question

我正在使用sendgrid发送电子邮件，并且使用以下代码可以正常工作，但没有附件。

package sendgrid;

import com.sendgrid.Content;
import com.sendgrid.Email;
import com.sendgrid.Mail;
import com.sendgrid.Method;
import com.sendgrid.Request;
import com.sendgrid.Response;
import com.sendgrid.SendGrid;
import java.io.IOException;

public class SendEmail {
    public static void main(String[] args) throws IOException {
    Email from = new Email("[e-mail]");
    String subject = "Hello World from the SendGrid Java Library!";

    Email to = new Email("[e-mail]");
    Content content = new Content("text/plain", "Hello, Email!");
    Mail mail = new Mail(from, subject, to, content);

    SendGrid sg = new SendGrid("SG.rIEh84OgQBybYEJcOMie1wd.AZqqdWNYXbOqTarUJcG-iSg0UtHJtCto4oe6tVzn6es");
    Request request = new Request();
    try {

      request.method = Method.POST;
      request.endpoint = "mail/send";
      request.body = mail.build();

      Response response = sg.api(request);
      System.out.println(response.statusCode);
      System.out.println(response.body);
      System.out.println(response.headers);

    } catch (IOException ex) {
      throw ex;
    }
  }

}

但是我需要发送附件，因此我搜索了github源和Web文档API，由于某种原因，没有javadocs，但是有一个示例GitHub
sendgrid，
所以我一直在尝试直到它起作用为止，我缩小了一些异常和响应代码，起初我是被禁止的未经授权，最好是响应202，表示有效且已排队（在此处检查），这是我的代码发送电子邮件和附件的任何方式，但是当您打开附件时，附件的大小为零，说无法打开或预览文件！

 package sendgrid;

    import com.sendgrid.Attachments;
    import com.sendgrid.Content;
    import com.sendgrid.Email;
    import com.sendgrid.Mail;
    import com.sendgrid.MailSettings;
    import com.sendgrid.Method;
    import com.sendgrid.Request;
    import com.sendgrid.SendGrid;
    import com.sendgrid.Setting;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.IOException;


    public class SendEmailAttachmentV2 {

        public static void main(String[] args) throws IOException {
            sendmail();
        }

        // Fully populated Mail object
        public static void sendmail() throws IOException {

            com.sendgrid.Response response1;

            Email from = new Email("[e-mail]");
            String subject = "Hello World from the SendGrid Java Library!";

            Email to = new Email("[e-mail]");
            Content content = new Content("text/plain", "Hello, Email!");
            Mail mail = new Mail(from, subject, to, content);

            File file = new File("C:\\x.png");
            byte[] fileData = null;
            try {
                fileData = org.apache.commons.io.IOUtils.toByteArray(new FileInputStream(file));
            } catch (IOException ex) {
            }

            Attachments attachments3 = new Attachments();            
            attachments3.setContent(new String(fileData, 0, (int) file.length(), "UTF-8"));
            attachments3.setType("image/png");//"application/pdf"
            attachments3.setFilename("x.png");
            attachments3.setDisposition("attachment");
            attachments3.setContentId("Banner");
            mail.addAttachments(attachments3);


            MailSettings mailSettings = new MailSettings();
            Setting sandBoxMode = new Setting();
            sandBoxMode.setEnable(true);
            mailSettings.setSandboxMode(sandBoxMode);

            SendGrid sg = new SendGrid("SG.1Hg78VK0TJ6kexUnByZUYg.LAa5A4GufssZ9lpPQdV6PcZCY6SZ9Xq6LvqfMRG0wesKw");
            Request request1 = new Request();
            try {
                request1.method = Method.POST;
                request1.endpoint = "mail/send";

                request1.body = mail.build();

                response1 = sg.api(request1);
                System.out.println(response1.statusCode);
                System.out.println(response1.body);
                System.out.println(response1.headers);

            } catch (IOException ex) {
                System.out.println(ex);
            }
        }

    }

仅供参考 ：使用从sendgrid控制台生成的生成的API密钥

Answer 1

当我执行代码时，我在netbeans的日志中收到以下消息

 202

 {X-Frame-Options=DENY, Server=nginx, Connection=keep-alive,
 X-Message-Id=vqVw2RtUShSVQ_ymVEVqaw, Content-Length=0, Date=Tue, 26
 Jul 2016 20:05:54 GMT, Content-Type=text/plain; charset=utf-8}

解决此问题的技巧是使用commons apache编解码器commons-
codec-1.8.jar
及其encodeAsString包中的方法对附件进行编码

org.apache.commons.codec.binary.Base64

Attachments attachments3 = new Attachments();
Base64 x = new Base64();
String imageDataString = x.encodeAsString(fileData);
attachments3.setContent(imageDataString);
attachments3.setType("image/png");//"application/pdf"
attachments3.setFilename("x.png");
attachments3.setDisposition("attachment");
attachments3.setContentId("Banner");
mail.addAttachments(attachments3);

作为响应 ， 即使content-length也被设置为0 。