[+/-] : Parsing Character-Separated Data with a Regular Expression

A line from a flat-file is typically formatted using a separator character to separate the fields. If the separator is simply a comma, tab, or single character, the StringTokenizer class can be used to parse the line into fields. If the separator is more complex (e.g., a space after a comma), a regular expression is needed. String.split() conveniently parses a line using a regular expression to specify the separator.

String.split() returns only the nondelimiter strings. To obtain the delimiter strings, see Parsing a String into Tokens Using a Regular Expression.

Note: The StringTokenizer does not conveniently handle empty fields properly. For example, given the line a,,b, rather than return three fields (the second being empty), the StringTokenizer returns two fields, discarding the empty field. String.split() properly handles empty fields.

// Parse a comma-separated string
String inputStr = "a,,b";
String patternStr = ",";
String[] fields = inputStr.split(patternStr);
// ["a", "", "b"]

// Parse a line whose separator is a comma followed by a space
inputStr = "a, b, c,d";
patternStr = ", ";
fields = inputStr.split(patternStr, -1);
// ["a", "b", "c,d"]

// Parse a line with and's and or's
inputStr = "a, b, and c";
patternStr = "[, ]+(andor)*[, ]*";
fields = inputStr.split(patternStr, -1);
// ["a", "b", "c"]

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[+/-] : Parsing a String into Tokens Using a Regular Expression

This example implements a tokenizer that uses regular expressions. The use of this tokenizer is similar to the StringTokenizer class in that you use it like an iterator to extract the tokens.

CharSequence inputStr = "a 1 2 b c 3 4";
String patternStr = "[a-z]";

// Set to false if only the tokens that match the pattern are to be returned.
// If true, the text between matching tokens are also returned.
boolean returnDelims = true;

// Create the tokenizer
Iterator tokenizer = new RETokenizer(inputStr, patternStr, returnDelims);

// Get the tokens (and delimiters)
for (; tokenizer.hasNext(); ) {
    String tokenOrDelim = (String)tokenizer.next();
}
// "", "a", " 1 2 ", "b", " ", "c"

class RETokenizer implements Iterator {
    // Holds the original input to search for tokens
    private CharSequence input;

    // Used to find tokens
    private Matcher matcher;

    // If true, the String between tokens are returned
    private boolean returnDelims;

    // The current delimiter value. If non-null, should be returned
    // at the next call to next()
    private String delim;

    // The current matched value. If non-null and delim=null,
    // should be returned at the next call to next()
    private String match;

    // The value of matcher.end() from the last successful match.
    private int lastEnd = 0;

    // patternStr is a regular expression pattern that identifies tokens.
    // If returnDelims delim is false, only those tokens that match the
    // pattern are returned. If returnDelims true, the text between
    // matching tokens are also returned. If returnDelims is true, the
    // tokens are returned in the following sequence - delimiter, token,
    // delimiter, token, etc. Tokens can never be empty but delimiters might
    // be empty (empty string).
    public RETokenizer(CharSequence input, String patternStr, boolean returnDelims) {
        // Save values
        this.input = input;
        this.returnDelims = returnDelims;

        // Compile pattern and prepare input
        Pattern pattern = Pattern.compile(patternStr);
        matcher = pattern.matcher(input);
    }

    // Returns true if there are more tokens or delimiters.
    public boolean hasNext() {
        if (matcher == null) {
        return false;
        }
        if (delim != null || match != null) {
        return true;
        }
        if (matcher.find()) {
        if (returnDelims) {
            delim = input.subSequence(lastEnd, matcher.start()).toString();
        }
        match = matcher.group();
        lastEnd = matcher.end();
        } else if (returnDelims && lastEnd < input.length()) {
        delim = input.subSequence(lastEnd, input.length()).toString();
        lastEnd = input.length();

        // Need to remove the matcher since it appears to automatically
        // reset itself once it reaches the end.
        matcher = null;
        }
        return delim != null || match != null;
    }

    // Returns the next token (or delimiter if returnDelims is true).
    public Object next() {
        String result = null;

        if (delim != null) {
        result = delim;
        delim = null;
        } else if (match != null) {
        result = match;
        match = null;
        }
        return result;
    }

    // Returns true if the call to next() will return a token rather
    // than a delimiter.
    public boolean isNextToken() {
        return delim == null && match != null;
    }

    // Not supported.
    public void remove() {
        throw new UnsupportedOperationException();
    }
}

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[+/-] : JMailer is a java mail client like phpmailer

package peace.org.mail;

import java.io.File;
import java.util.ArrayList;
import java.util.Date;
import java.util.Hashtable;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;

import javax.activation.DataHandler;
import javax.activation.FileDataSource;
import javax.mail.Address;
import javax.mail.Authenticator;
import javax.mail.Multipart;
import javax.mail.PasswordAuthentication;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.Message.RecipientType;
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 java mail client is like phpmailer
 * author:freecode-freecode.blogspot.com
 */
public class JMailer {
 // ///////////////////////////////////////////////
 // PUBLIC VARIABLES
 // ///////////////////////////////////////////////
 /**
  * Email priority (1 = High, 3 = Normal, 5 = low).
  */
 public int priority = 3;

 /**
  * Sets the CharSet of the message.
  */
 public String charSet = "iso-8859-1";

 /**
  * Sets the Content-type of the message.
  */
 public String contentType = "text/plain";

 /**
  * Sets the Encoding of the message. Options for this are "8bit", "7bit",
  * "binary", "base64", and "quoted-printable". Content-Transfer-Encoding
  */
 public String encoding = "8bit";

 /**
  * Sets the From email address for the message.
  */
 public String from = "root@localhost";

 /**
  * Sets the Sender email (Return-Path) of the message. If not empty, will be
  * sent via -f to sendmail or as 'MAIL FROM' in smtp mode.
  */
 public String sender = "";

 /**
  * Sets the Subject of the message.
  */
 public String subject = "";

 /**
  * Sets the Body of the message. This can be either an HTML or text body. If
  * HTML then run IsHTML(true).
  */
 public String body = "";

 // ///////////////////////////////////////////////
 // SMTP VARIABLES
 // ///////////////////////////////////////////////

 /**
  * Sets the SMTP hosts. All hosts must be separated by a semicolon. You can
  * also specify a different port for each host by using this format:
  * [hostname:port] (e.g. "smtp1.example.com:25;smtp2.example.com"). Hosts will
  * be tried in order.
  */
 public String host = "localhost";

 /**
  * Sets the default SMTP server port.(25)
  */
 public int port = 25;

 /**
  * Sets the SMTP HELO of the message ($Hostname).
  */
 public String helo = "";

 /**
  * Sets SMTP authentication. Utilizes the Username and Password variables.
  * (false)
  */
 public boolean smtpAuth = false;

 /**
  * Sets SMTP username.
  */
 public String username = "";

 /**
  * Sets SMTP password.
  */
 public String password = "";

 // private
 // $smtp = NULL;
 private StringBuffer to = new StringBuffer();
 private StringBuffer cc = new StringBuffer();
 private StringBuffer bcc = new StringBuffer();
 private StringBuffer replyTo = new StringBuffer();
 // 
 private ArrayList attachment = new ArrayList(0);
 private Date sendDate = new Date();

 private Hashtable _customHeader = new Hashtable();
 private String _message_type = "plain";

 private static String COMMA = ",";

 public JMailer() {}

 /**
  * Sets message type to HTML.
  *
  * @param isHTML
  */
 public void setHTML(boolean isHTML) {
   if (isHTML)
     contentType = "text/html";
   else
     contentType = "text/plain";
 }

 /**
  * Adds a "To" address.
  *
  * @param address
  */
 public void addAddress(String address) {
   to.append(address).append(COMMA);
 }

 /**
  * Adds a "Cc" address.
  *
  * @param address
  */
 public void addCC(String address) {
   cc.append(address).append(COMMA);
 }

 /**
  * Adds a "Bcc" address.
  *
  * @param address
  */
 public void addBCC(String address) {
   bcc.append(address).append(COMMA);
 }

 /**
  * Adds a "Reply-to" address
  *
  * @param address
  */
 public void addReplyTo(String address) {
   replyTo.append(address).append(COMMA);
 }

 /**
  * Adds a custom header.
  *
  * @param name
  * @param value
  */
 public void addHeader(String name, String value) {
   _customHeader.put(name, value);
 }

 public void removeHeader(String name) {
   _customHeader.remove(name);
 }

 /**
  * Sets send date.
  *
  * @param d
  */
 public void setSendDate(Date d) {
   sendDate = d;
 }

 public void addAttachment(File f) {
   if (f != null && f.isFile())
     attachment.add(f);
 }

 public void AddAttachment(String file) {
   File f = new File(file);
   if (f.isFile())
     attachment.add(f);
 }

 /**
  * Send message.
  *
  * @return
  */
 public boolean send() {
   boolean ok = false;

   Session session = createSession();

   final MimeMessage msg = new MimeMessage(session);
   try {
     msg.setRecipients(RecipientType.TO, parseAddress(to));

     Address[] ccAddress = parseAddress(cc);
     if (ccAddress != null)
       msg.setRecipients(RecipientType.CC, ccAddress);
     Address[] bccAddress = parseAddress(bcc);
     if (bccAddress != null)
       msg.setRecipients(RecipientType.BCC, bccAddress);
     Address[] replyToAddress = parseAddress(replyTo);
     if (replyToAddress != null)
       msg.setReplyTo(replyToAddress);
     if (!"".equals(from)) {
       if(!"".equals(sender))
         msg.setFrom(new InternetAddress(from,sender));
       else
         msg.setFrom(new InternetAddress(from));
     }

     msg.setSentDate(sendDate);

     msg.setSubject(subject);
     msg.addHeaderLine("Content-Transfer-Encoding: " + encoding);
     msg.addHeaderLine("X-Priority: " + priority);

     msg.addHeaderLine("Content-Type: " + contentType + "; charset="
             + charSet);
     // add custom header
     Set keyset = _customHeader.keySet();
     for (Iterator keys = keyset.iterator(); keys.hasNext();) {
       String name = (String) keys.next();
       String value = (String) _customHeader.get(name);
       msg.addHeader(name, value);
     }

     // attach the file to the message
     if (attachment.size() > 0) {

       // create and fill the message body
       MimeBodyPart body1 = new MimeBodyPart();
       body1.setContent(body, contentType + "; charset=" + charSet);

       // create the Multipart and its parts to it
       Multipart mp = new MimeMultipart();
       mp.addBodyPart(body1);

       for (int i = 0; i < attachment.size(); i++) {
         FileDataSource fds = new FileDataSource((File) attachment.get(i));
         MimeBodyPart body2 = new MimeBodyPart();
         body2.setDataHandler(new DataHandler(fds));
         body2.setFileName(fds.getName());

         mp.addBodyPart(body2);
       }

       msg.setContent(mp);
     } else {
       msg.setContent(body, contentType + "; charset=" + charSet);
     }

     Transport.send(msg);
     ok = true;
   } catch (Exception e) {
     e.printStackTrace();
   }

   return ok;
 }

 // create a session
 private Session createSession() {
   Authenticator authenticator = null;
   Properties props = new Properties();
   props.put("mail.smtp.host", host);

   if (smtpAuth) {
     props.put("mail.smtp.auth", "true");// 身份验证
     authenticator = new Authenticator() {
       public PasswordAuthentication getPasswordAuthentication() {

         return new PasswordAuthentication(username, password);
       }
     };
   }
   return Session.getInstance(props, authenticator);
 }

 private Address[] parseAddress(StringBuffer bufAddress)
     throws AddressException {
   String addresses = bufAddress.toString();

   if ("".equals(addresses))
     return null;

   if (addresses.endsWith(",")) {
     addresses = addresses.substring(0, addresses.length() - 1);
   }

   return InternetAddress.parse(addresses);
 }
}

JMailer usage:

   JMailer mailer = new JMailer();
   mailer.charSet = "utf-8"
   mailer.from = "noreply@freecode.com";  
   mailer.host = "127.0.0.1";//or your mail SMTP server

   mailer.subject = "JMailer example";
   mailer.body = "hi Jmi,...";

   mailer.addAddress("Jmi@yahoo.com");
   mailer.addBCC("son@gmail.com");
   mailer.setHTML(true);

   mailer.send();

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[+/-] : How To Send E-Mail By JavaMail API

This example demonstrates the simplest program that will send a textual E-mail message to a single recipient.

import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

public class SendMail {
public static void send(String smtpHost, int smtpPort,
String from, String to,
String subject, String content)
throws AddressException, MessagingException {
// Create a mail session
java.util.Properties props = new java.util.Properties();
props.put("mail.smtp.host", smtpHost);
props.put("mail.smtp.port", ""+smtpPort);
Session session = Session.getDefaultInstance(props, null);

// Construct the message
Message msg = new MimeMessage(session);
msg.setFrom(new InternetAddress(from));
msg.setRecipient(Message.RecipientType.TO, new InternetAddress(to));
msg.setSubject(subject);
msg.setText(content);

// Send the message
Transport.send(msg);
}

public static void main(String[] args) throws Exception {
// Send a test message
SendMail sender = new SendMail();
sender.send("hostname", 25, "luotuo.name@gmail.com", "tuoluo@gmail.com", "javamail example ", "How to send mail by javamail API?");
}
}

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