android後台不借助Intent發送Email

 下面是對郵件發送功能的封裝，使用這些方法可以很容易地發送電子郵件，甚至可以添加附件。
import java.util.Date;
import java.util.Properties;
import javax.activation.CommandMap;
import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.activation.MailcapCommandMap;
import javax.mail.BodyPart;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;


public class Mail extends javax.mail.Authenticator {
private String _user;
private String _pass;

private String[] _to;
private String _from;

private String _port;
private String _sport;

private String _host;

private String _subject;
private String _body;

private boolean _auth;

private boolean _debuggable;

private Multipart _multipart;


public Mail() {
_host = "smtp.gmail.com"; // default smtp server
_port = "465"; // default smtp port
_sport = "465"; // default socketfactory port

_user = ""; // username
_pass = ""; // password
_from = ""; // email sent from
_subject = ""; // email subject
_body = ""; // email body

_debuggable = false; // debug mode on or off - default off
_auth = true; // smtp authentication - default on

_multipart = new MimeMultipart();

// There is something wrong with MailCap, javamail can not find a handler for the multipart/mixed part, so this bit needs to be added.
MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap();
mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html");
mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml");
mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain");
mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed");
mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822");
CommandMap.setDefaultCommandMap(mc);
}

public Mail(String user, String pass) {
this();

_user = user;
_pass = pass;
}

public boolean send() throws Exception {
Properties props = _setProperties();

if(!_user.equals("") && !_pass.equals("") && _to.length > 0 && !_from.equals("") && !_subject.equals("") && !_body.equals("")) {
Session session = Session.getInstance(props, this);

MimeMessage msg = new MimeMessage(session);

msg.setFrom(new InternetAddress(_from));

InternetAddress[] addressTo = new InternetAddress[_to.length];
for (int i = 0; i < _to.length; i++) {
addressTo[i] = new InternetAddress(_to[i]);
}
msg.setRecipients(MimeMessage.RecipientType.TO, addressTo);

msg.setSubject(_subject);
msg.setSentDate(new Date());

// setup message body
BodyPart messageBodyPart = new MimeBodyPart();
messageBodyPart.setText(_body);
_multipart.addBodyPart(messageBodyPart);

// Put parts in message
msg.setContent(_multipart);

// send email
Transport.send(msg);

return true;
} else {
return false;
}
}

public void addAttachment(String filename) throws Exception {
BodyPart messageBodyPart = new MimeBodyPart();
DataSource source = new FileDataSource(filename);
messageBodyPart.setDataHandler(new DataHandler(source));
messageBodyPart.setFileName(filename);

_multipart.addBodyPart(messageBodyPart);
}

@Override
public PasswordAuthentication getPasswordAuthentication() {
return new PasswordAuthentication(_user, _pass);
}

private Properties _setProperties() {
Properties props = new Properties();

props.put("mail.smtp.host", _host);

if(_debuggable) {
props.put("mail.debug", "true");
}

if(_auth) {
props.put("mail.smtp.auth", "true");
}

props.put("mail.smtp.port", _port);
props.put("mail.smtp.socketFactory.port", _sport);
props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory");
props.put("mail.smtp.socketFactory.fallback", "false");

return props;
}

// the getters and setters
public String getBody() {
}

public void setBody(String _body) {
this._body = _body;
}

// more of the getters and setters …..
}

And now I'm going to go through each bit of code

public Mail() {
_host = "smtp.gmail.com"; // default smtp server
_port = "465"; // default smtp port
_sport = "465"; // default socketfactory port

_user = ""; // username
_pass = ""; // password
_from = ""; // email sent from
_subject = ""; // email subject
_body = ""; // email body

_debuggable = false; // debug mode on or off - default off
_auth = true; // smtp authentication - default on

_multipart = new MimeMultipart();

// There is something wrong with MailCap, javamail can not find a handler for the multipart/mixed part, so this bit needs to be added.
MailcapCommandMap mc = (MailcapCommandMap) CommandMap.getDefaultCommandMap();
mc.addMailcap("text/html;; x-java-content-handler=com.sun.mail.handlers.text_html");
mc.addMailcap("text/xml;; x-java-content-handler=com.sun.mail.handlers.text_xml");
mc.addMailcap("text/plain;; x-java-content-handler=com.sun.mail.handlers.text_plain");
mc.addMailcap("multipart/*;; x-java-content-handler=com.sun.mail.handlers.multipart_mixed");
mc.addMailcap("message/rfc822;; x-java-content-handler=com.sun.mail.handlers.message_rfc822");
CommandMap.setDefaultCommandMap(mc);
}

public Mail(String user, String pass) {
this();

_user = user;
_pass = pass;
}
在這段代碼中，我們初始化了類mail屬性，並設置為默認值。
另外，裡面的JavaMail MIME類型需要注意看。裡面有一個注釋說明。
裡面的兩個2個構造函數也要仔細看，你可以通過其中一個傳遞用戶名跟密碼進去。
public boolean send() throws Exception {
Properties props = _setProperties();

if(!_user.equals("") && !_pass.equals("") && _to.length > 0 && !_from.equals("") && !_subject.equals("") && !_body.equals("")) {
Session session = Session.getInstance(props, this);

MimeMessage msg = new MimeMessage(session);