import org.jivesoftware.smackx.packet.RosterExchange; //导入依赖的package包/类
private void init() {
	// Listens for all roster exchange packets and fire the roster exchange
	// listeners.
	packetListener = new PacketListener() {
		public void processPacket(Packet packet) {
			Message message = (Message) packet;
			RosterExchange rosterExchange = (RosterExchange) message
					.getExtension("x", "jabber:x:roster");
			// Fire event for roster exchange listeners
			fireRosterExchangeListeners(message.getFrom(),
					rosterExchange.getRosterEntries());
		};

	};
	con.addPacketListener(packetListener, packetFilter);
}
 

import org.jivesoftware.smackx.packet.RosterExchange; //导入依赖的package包/类
/**
 * Sends a roster to userID. All the entries of the roster will be sent to the
 * target user.
 * 
 * @param roster the roster to send
 * @param targetUserID the user that will receive the roster entries
 */
public void send(Roster roster, String targetUserID) {
    // Create a new message to send the roster
    Message msg = new Message(targetUserID);
    // Create a RosterExchange Package and add it to the message
    RosterExchange rosterExchange = new RosterExchange(roster);
    msg.addExtension(rosterExchange);

    // Send the message that contains the roster
    con.sendPacket(msg);
}
 

import org.jivesoftware.smackx.packet.RosterExchange; //导入依赖的package包/类
private void init() {
    // Listens for all roster exchange packets and fire the roster exchange listeners.
    packetListener = new PacketListener() {
        public void processPacket(Packet packet) {
            Message message = (Message) packet;
            RosterExchange rosterExchange =
                (RosterExchange) message.getExtension("x", "jabber:x:roster");
            // Fire event for roster exchange listeners
            fireRosterExchangeListeners(message.getFrom(), rosterExchange.getRosterEntries());
        };

    };
    con.addPacketListener(packetListener, packetFilter);
}
 

import org.jivesoftware.smackx.packet.RosterExchange; //导入依赖的package包/类
/**
 * Sends a roster to userID. All the entries of the roster will be sent to
 * the target user.
 * 
 * @param roster
 *            the roster to send
 * @param targetUserID
 *            the user that will receive the roster entries
 */
public void send(Roster roster, String targetUserID) {
	// Create a new message to send the roster
	Message msg = new Message(targetUserID);
	// Create a RosterExchange Package and add it to the message
	RosterExchange rosterExchange = new RosterExchange(roster);
	msg.addExtension(rosterExchange);

	// Send the message that contains the roster
	con.sendPacket(msg);
}