java实现邮件发送功能_电子邮件是啥

我使用sendgrid发送电子邮件,使用以下代码工作正常

但它没有附件.

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(“test@example.com”);

String subject = “Hello World from the SendGrid Java Library!”;

Email to = new Email(“shareef@gmail.com”);

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;

}

}

}

但我需要的是发送附件,所以我搜索github源和Web文档API,由于某种原因没有javadocs但有一个例子GitHub sendgrid所以我尝试,直到它工作,我缩小了一些例外和响应代码,起初我是未经授权的禁止,它更好地响应202,意味着有效和排队(check here)这里任何方式是我的代码,发送电子邮件和附件,但当你打开附件的零大小,并说不能打开或预览文件！

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(“shareef@gmail.com”);

String subject = “Hello World from the SendGrid Java Library!”;

Email to = new Email(“shareef@gmail.com”);

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