使用Smack 4.1的XMPP客户端在登录期间给出NullPointerException

Question

我正在尝试使用Smack 4.1.0-rc3来实现连接到ejabberd xmpp服务器的java xmpp客户端.我使用以下代码连接到服务器.

    XMPPTCPConnectionConfiguration connConfig =    XMPPTCPConnectionConfiguration
            .builder()
            .setServiceName("example.com")
            .setHost("192.168.56.101")
            .setPort(5222)
            .setCompressionEnabled(false)
            .setSecurityMode(SecurityMode.disabled)
            .setHostnameVerifier(new HostnameVerifier() {
                public boolean verify(String arg0, SSLSession arg1) {
                    return true;
                }
            })
            .setUsernameAndPassword(user, pass).build();

    connection = new XMPPTCPConnection(connConfig);
    connection.connect();
    connection.login();

执行'connection.login()'时,我得到以下NullPointerException.

Exception in thread "main" java.lang.NullPointerException
at org.jivesoftware.smack.util.stringencoder.Base64.encode(Base64.java:64)
at org.jivesoftware.smack.util.stringencoder.Base64.encode(Base64.java:60)
at org.jivesoftware.smack.util.stringencoder.Base64.encodeToString(Base64.java:42)
at org.jivesoftware.smack.sasl.SASLMechanism.authenticate(SASLMechanism.java:199)
at org.jivesoftware.smack.sasl.SASLMechanism.authenticate(SASLMechanism.java:169)
at org.jivesoftware.smack.SASLAuthentication.authenticate(SASLAuthentication.java:236)
at org.jivesoftware.smack.tcp.XMPPTCPConnection.loginNonAnonymously(XMPPTCPConnection.java:365)
at org.jivesoftware.smack.AbstractXMPPConnection.login(AbstractXMPPConnection.java:452)
at org.jivesoftware.smack.AbstractXMPPConnection.login(AbstractXMPPConnection.java:410)
at org.org.oodlezz.unio.jabber.client.XmppClient.connect(XmppClient.java:88)
at org.org.oodlezz.unio.jabber.client.Client.main(Client.java:32)

我在代码中做错了吗？你能指点一下使用Smack 4.1.0-rc3的正确例子吗？

Answer 1

这个页面上的其他答案有部分答案,但尝试它们我发现真正缺少的是对smack-java7库的依赖.添加此依赖项会导致调用初始化程序,设置base64encoder,因此NullPointerException消失.

在Android上,用smack-android替换smack-java7.

Answer 2

您的代码没问题,但可能需要正确的依赖项,您可以将它放在pom.xml文件中

<dependencies>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-java7</artifactId>
        <version>4.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-tcp</artifactId>
        <version>4.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-im</artifactId>
        <version>4.1.1</version>
    </dependency>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-extensions</artifactId>
        <version>4.1.1</version>
    </dependency>
</dependencies>

这基于:https://github.com/igniterealtime/Smack/wiki/Smack-4.1-Readme-and-Upgrade-Guide

你可以把你需要的smack版本.

关于maven的一些第一步,如果你不熟悉它,这可能对你有用:https://maven.apache.org/guides/getting-started/maven-in-five-minutes.html

希望对你有所帮助!

Answer 3

我使用的是 4.1.0-rc3。就我而言，我没有遇到 NPE。该示例有效。

以下是pom.xml的部分。

pom.xml

<properties>
    <smack.version>4.1.0-rc3</smack.version>
</properties>
...
<dependencies>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-core</artifactId>
        <version>${smack.version}</version>
    </dependency>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-tcp</artifactId>
        <version>${smack.version}</version>
    </dependency>
    <dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-java7</artifactId>
        <version>${smack.version}</version>
    </dependency>
...
</dependencies>
...

示例代码只是，

AbstractXMPPConnection conn = new XMPPTCPConnection("xxx", "yyy", "zzz");

conn.connect();
conn.login();