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); 

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; 
} 
} 
這是發送的方法，裡面有設置了數據屬性，然後執行了發送操作。
 
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); 
} 
這是添加附件的函數，不過需要在發送之前調用。
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; 
}