Java Smack如何處理連接斷開

Smack 是一個用于處理 XMPP（可擴展消息與出席協議）的 Java 庫。處理連接斷開的方法如下：

1. 添加依賴

首先，確保在項目的 pom.xml 文件中添加了 Smack 庫的依賴：

<dependency>
    <groupId>org.igniterealtime.smack</groupId>
    <artifactId>smack-java7</artifactId>
    <version>4.4.2</version>
</dependency>
<dependency>
    <groupId>org.igniterealtime.smack</groupId>
    <artifactId>smack-tcp</artifactId>
    <version>4.4.2</version>
</dependency>
<dependency>
    <groupId>org.igniterealtime.smack</groupId>
    <artifactId>smack-extensions</artifactId>
    <version>4.4.2</version>
</dependency>

2. 建立連接

使用 Smack 庫建立 XMPP 連接：

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;
import org.jivesoftware.smack.tcp.XMPPTCPConnectionConfiguration;

public class SmackDemo {
    public static void main(String[] args) {
        ConnectionConfiguration config = new XMPPTCPConnectionConfiguration.Builder("example.com")
                .setUsernameAndPassword("username", "password")
                .setSecurityMode(ConnectionConfiguration.SecurityMode.disabled)
                .build();

        Connection connection = new XMPPTCPConnection(config);
        try {
            connection.connect();
        } catch (XMPPException e) {
            e.printStackTrace();
        }
    }
}

3. 處理連接斷開

為了處理連接斷開，需要實現 Connection.Listener 接口并重寫 connectionClosed() 方法。例如：

import org.jivesoftware.smack.Connection;
import org.jivesoftware.smack.ConnectionConfiguration;
import org.jivesoftware.smack.XMPPException;
import org.jivesoftware.smack.tcp.XMPPTCPConnection;
import org.jivesoftware.smack.tcp.XMPPTCPConnectionConfiguration;

public class SmackDemo {
    public static void main(String[] args) {
        ConnectionConfiguration config = new XMPPTCPConnectionConfiguration.Builder("example.com")
                .setUsernameAndPassword("username", "password")
                .setSecurityMode(ConnectionConfiguration.SecurityMode.disabled)
                .build();

        Connection connection = new XMPPTCPConnection(config);
        connection.addAsyncStanzaListener(new StanzaTypeFilter(Message.class), new MessageListener());
        connection.addAsyncStanzaListener(new StanzaTypeFilter(Presence.class), new PresenceListener());
        try {
            connection.connect();
        } catch (XMPPException e) {
            e.printStackTrace();
        }
    }

    static class MessageListener implements StanzaListener {
        @Override
        public void processStanza(Stanza stanza) {
            // 處理消息
        }
    }

    static class PresenceListener implements StanzaListener {
        @Override
        public void processStanza(Stanza stanza) {
            // 處理在線狀態
        }
    }

    public static class MyConnectionListener implements Connection.Listener {
        @Override
        public void connectionClosed() {
            System.out.println("連接已斷開");
            // 在這里處理連接斷開后的邏輯，例如重新連接或清理資源
        }

        @Override
        public void connectionFailed(Exception e) {
            System.out.println("連接失敗");
            e.printStackTrace();
        }
    }
}

在這個例子中，我們創建了一個名為 MyConnectionListener 的類，實現了 Connection.Listener 接口。我們重寫了 connectionClosed() 方法，當連接斷開時，這個方法會被調用。在這個方法里，你可以處理連接斷開后的邏輯，例如重新連接或清理資源。