public class SMTPClient extends SMTP
SocketClient
, you must
first connect to the server with connect
before doing anything, and finally
disconnect
after you're completely finished interacting with the server. Then you need to check the
SMTP reply code to see if the connection was successful. For example:
try { int reply; client.connect("mail.foobar.com"); System.out.print(client.getReplyString()); // After connection attempt, you should check the reply code to verify // success. reply = client.getReplyCode(); if(!SMTPReply.isPositiveCompletion(reply)) { client.disconnect(); System.err.println("SMTP server refused connection."); System.exit(1); } // Do useful stuff here. ... } catch(IOException e) { if(client.isConnected()) { try { client.disconnect(); } catch(IOException f) { // do nothing } } System.err.println("Could not connect to server."); e.printStackTrace(); System.exit(1); }
Immediately after connecting is the only real time you need to check the reply code (because connect is of type void). The convention for all the SMTP
command methods in SMTPClient is such that they either return a boolean value or some other value. The boolean methods return true on a successful completion
reply from the SMTP server and false on a reply resulting in an error condition or failure. The methods returning a value other than boolean return a value
containing the higher level data produced by the SMTP command, or null if a reply resulted in an error condition or failure. If you want to access the exact
SMTP reply code causing a success or failure, you must call getReplyCode
after a success or failure.
You should keep in mind that the SMTP server may choose to prematurely close a connection for various reasons. The SMTPClient class will detect a premature
SMTP server connection closing when it receives a SMTPReply.SERVICE_NOT_AVAILABLE
response to a command. When that occurs, the method encountering that reply will throw an SMTPConnectionClosedException
.
SMTPConectionClosedException
is a subclass of IOException
and therefore need not be caught separately, but if you are going to
catch it separately, its catch block must appear before the more general IOException
catch block. When you encounter an
SMTPConnectionClosedException
, you must disconnect the connection with disconnect()
to properly
clean up the system resources used by SMTPClient. Before disconnecting, you may check the last reply code and text with
getReplyCode
, getReplyString
, and
getReplyStrings
.
Rather than list it separately for each method, we mention here that every method communicating with the server and throwing an IOException can also throw a
MalformedServerReplyException
, which is a subclass of IOException. A MalformedServerReplyException will be thrown when the
reply received from the server deviates enough from the protocol specification that it cannot be interpreted in a useful manner despite attempts to be as
lenient as possible.
_commandSupport_, DEFAULT_PORT, encoding
_defaultPort_, _hostname_, _input_, _output_, _serverSocketFactory_, _socket_, _socketFactory_, _timeout_, connectTimeout, NETASCII_EOL
Constructor and Description |
---|
SMTPClient()
Default SMTPClient constructor.
|
SMTPClient(String encoding)
Overloaded constructor that takes an encoding specification
|
Modifier and Type | Method and Description |
---|---|
boolean |
addRecipient(RelayPath path)
Add a recipient for a message using the SMTP RCPT command, specifying a forward relay path.
|
boolean |
addRecipient(String address)
Add a recipient for a message using the SMTP RCPT command, the recipient's email address.
|
boolean |
completePendingCommand()
At least one SMTPClient method (
sendMessageData ) does not complete the entire sequence of SMTP commands to complete a
transaction. |
String |
listHelp()
Fetches the system help information from the server and returns the full string.
|
String |
listHelp(String command)
Fetches the help information for a given command from the server and returns the full string.
|
boolean |
login()
Login to the SMTP server by sending the HELO command with the client hostname as an argument.
|
boolean |
login(String hostname)
Login to the SMTP server by sending the HELO command with the given hostname as an argument.
|
boolean |
logout()
Logout of the SMTP server by sending the QUIT command.
|
boolean |
reset()
Aborts the current mail transaction, resetting all server stored sender, recipient, and mail data, cleaing all buffers and tables.
|
Writer |
sendMessageData()
Send the SMTP DATA command in preparation to send an email message.
|
boolean |
sendNoOp()
Sends a NOOP command to the SMTP server.
|
boolean |
sendShortMessageData(String message)
A convenience method for sending short messages.
|
boolean |
sendSimpleMessage(String sender,
String[] recipients,
String message)
A convenience method for a sending short email without having to explicitly set the sender and recipient(s).
|
boolean |
sendSimpleMessage(String sender,
String recipient,
String message)
A convenience method for a sending short email without having to explicitly set the sender and recipient(s).
|
boolean |
setSender(RelayPath path)
Set the sender of a message using the SMTP MAIL command, specifying a reverse relay path.
|
boolean |
setSender(String address)
Set the sender of a message using the SMTP MAIL command, specifying the sender's email address.
|
boolean |
verify(String username)
Verify that a username or email address is valid, i.e., that mail can be delivered to that mailbox on the server.
|
_connectAction_, data, disconnect, expn, getCommandSupport, getReply, getReplyCode, getReplyString, getReplyStrings, helo, help, help, mail, noop, quit, rcpt, removeProtocolCommandistener, rset, saml, send, sendCommand, sendCommand, sendCommand, sendCommand, soml, turn, vrfy
addProtocolCommandListener, applySocketAttributes, connect, connect, connect, connect, connect, connect, createCommandSupport, fireCommandSent, fireReplyReceived, getCharset, getCharsetName, getConnectTimeout, getDefaultPort, getDefaultTimeout, getKeepAlive, getLocalAddress, getLocalPort, getProxy, getReceiveBufferSize, getRemoteAddress, getRemotePort, getSendBufferSize, getServerSocketFactory, getSoLinger, getSoTimeout, getTcpNoDelay, isAvailable, isConnected, removeProtocolCommandListener, setCharset, setConnectTimeout, setDefaultPort, setDefaultTimeout, setKeepAlive, setProxy, setReceiveBufferSize, setSendBufferSize, setServerSocketFactory, setSocketFactory, setSoLinger, setSoTimeout, setTcpNoDelay, verifyRemote
public SMTPClient()
public SMTPClient(String encoding)
encoding
- The encoding to usepublic boolean addRecipient(RelayPath path) throws IOException
path
- The forward relay path pointing to the recipient.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean addRecipient(String address) throws IOException
address
- The recipient's email address.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean completePendingCommand() throws IOException
sendMessageData
) does not complete the entire sequence of SMTP commands to complete a
transaction. These types of commands require some action by the programmer after the reception of a positive intermediate command. After the programmer's
code completes its actions, it must call this method to receive the completion reply from the server and verify the success of the entire transaction.
For example,
writer = client.sendMessageData(); if (writer == null) // failure return false; header = new SimpleSMTPHeader("foobar@foo.com", "foo@foobar.com", "Re: Foo"); writer.write(header.toString()); writer.write("This is just a test"); writer.close(); if (!client.completePendingCommand()) // failure return false;
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public String listHelp() throws IOException
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public String listHelp(String command) throws IOException
command
- The command on which to ask for help.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean login() throws IOException
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean login(String hostname) throws IOException
hostname
- The hostname with which to greet the SMTP server.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean logout() throws IOException
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean reset() throws IOException
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public Writer sendMessageData() throws IOException
You must not issue any commands to the SMTP server (i.e., call any (other methods) until you finish writing to the returned Writer instance and close it. The SMTP protocol uses the same stream for issuing commands as it does for returning results. Therefore the returned Writer actually writes directly to the SMTP connection. After you close the writer, you can execute new commands. If you do not follow these requirements your program will not work properly.
You can use the provided SimpleSMTPHeader
class to construct a bare minimum header. To construct more complicated
headers you should refer to RFC 5322. When the Java Mail API is finalized, you will be able to use it to compose fully compliant Internet text messages.
The DotTerminatedMessageWriter takes care of doubling line-leading dots and ending the message with a single dot upon closing, so all you have to worry
about is writing the header and the message.
Upon closing the returned Writer, you need to call completePendingCommand()
to finalize the transaction and verify its
success or failure from the server reply.
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.sendShortMessageData(String)
public boolean sendNoOp() throws IOException
SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean sendShortMessageData(String message) throws IOException
sendMessageData()
and writes the
specified String to it. After writing the message, this method calls completePendingCommand()
to finalize the
transaction and returns its success or failure.
message
- The short email message to send. This must include the headers and the body, but not the trailing "."SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean sendSimpleMessage(String sender, String recipient, String message) throws IOException
setSender
and addRecipient
, and then sends the message using sendShortMessageData
.
sender
- The email address of the sender.recipient
- The email address of the recipient.message
- The short email message to send. This must include the headers and the body, but not the trailing "."SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean sendSimpleMessage(String sender, String[] recipients, String message) throws IOException
setSender
and addRecipient
, and then sends the message using
sendShortMessageData
.
Note that the method ignores failures when calling addRecipient
so long as at least one call succeeds. If no recipients can
be successfully added then the method will fail (and does not attempt to send the message)
sender
- The email address of the sender.recipients
- An array of recipient email addresses.message
- The short email message to send. This must include the headers and the body, but not the trailing "."SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean setSender(RelayPath path) throws IOException
path
- The reverse relay path pointing back to the sender.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean setSender(String address) throws IOException
address
- The sender's email address.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.public boolean verify(String username) throws IOException
username
- The username or email address to validate.SMTPConnectionClosedException
- If the SMTP server prematurely closes the connection as a result of the client being idle or some other reason
causing the server to send SMTP reply code 421. This exception may be caught either as an IOException or
independently as itself.IOException
- If an I/O error occurs while either sending a command to the server or receiving a reply from the server.Copyright © 2001–2022 The Apache Software Foundation. All rights reserved.