Java XMPP clint with smack 4.1 NoClassDefFoundError:

Question

我正在尝试使用 smack 4.1.1 编写 XMPP Clint。我已将 smack jar 文件添加到构建路径中。我正在使用 eclipse IDE 来编写代码。

但是，当我尝试运行应用程序时，我得到了 NoClassDefFoundErrors。我修复了其中一些错误，将 xpp3、jxmpp 和 minidns jar 文件添加到构建路径中。然而，我收到以下错误。

Exception in thread "main" java.lang.NoClassDefFoundError: org/jxmpp/util/cache/ExpirationCache
at org.jivesoftware.smack.util.dns.minidns.MiniDnsResolver.<clinit>(MiniDnsResolver.java:46)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:274)
at org.jivesoftware.smack.SmackInitialization.loadSmackClass(SmackInitialization.java:213)
at org.jivesoftware.smack.SmackInitialization.parseClassesToLoad(SmackInitialization.java:193)
at org.jivesoftware.smack.SmackInitialization.processConfigFile(SmackInitialization.java:163)
at org.jivesoftware.smack.SmackInitialization.processConfigFile(SmackInitialization.java:148)
at org.jivesoftware.smack.SmackInitialization.<clinit>(SmackInitialization.java:116)
at org.jivesoftware.smack.SmackConfiguration.getVersion(SmackConfiguration.java:96)
at org.jivesoftware.smack.ConnectionConfiguration.<clinit>(ConnectionConfiguration.java:38)
at JabberSmackAPI.login(JabberSmackAPI.java:29)
at JabberSmackAPI.main(JabberSmackAPI.java:76)
Caused by: java.lang.ClassNotFoundException: org.jxmpp.util.cache.ExpirationCache
    at java.net.URLClassLoader.run(URLClassLoader.java:366)
    at java.net.URLClassLoader.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    ... 12 more

如何解决这个问题？

网上建议使用gradle或者maven来搭建。如果是这样，你能帮我如何使用它吗？我以前从未使用过它们。

Answer 1

根据下面的堆栈跟踪

Caused by: java.lang.ClassNotFoundException: org.jxmpp.util.cache.ExpirationCache
at java.net.URLClassLoader.run(URLClassLoader.java:366)
at java.net.URLClassLoader.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)

您的 class 路径中似乎缺少 jxmpp-util-cache-0.5.0-alpha2.jar。 Download 并将此 jar 添加到应用程序的 lib/ 目录中。

In the internet, it is advised to use gradle or maven for building the same. If so, can you help me how to use the same?

在 eclipse 中创建一个 meven 项目。如果您是 meven 项目的新手，请参考

How to create a Java project with Maven

并将以下依赖项添加到您的 meven 构建项目的 pom.xml

<dependency>
   <groupId>org.igniterealtime.smack</groupId>
      <artifactId>smack-java7</artifactId>
      <version>4.1.0</version>
 </dependency>
<dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-tcp</artifactId>
        <version>4.1.0</version>
</dependency>
<dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-im</artifactId>
        <version>4.1.0</version>
</dependency>
<dependency>
        <groupId>org.igniterealtime.smack</groupId>
        <artifactId>smack-extensions</artifactId>
        <version>4.1.0</version>
</dependency>

有关详细信息，请参阅此 link

Java XMPP clint with smack 4.1 NoClassDefFoundError:

Java XMPP clint with smack 4.1 NoClassDefFoundError:

eclipse

smack

gradle

maven

build.gradle