我是 Java 新手，但我必须用它来做一个与 WebSocket 相关的小型项目。
因此，我在 VirtualBox 中的 CentOS 7 上安装了 JDK 1.8.0 和 NetBeans 8.1。
我在pom.xml中添加了tyrus-standalone-client-jdk 1.12插件来制作独立的 Websocket 客户端，并且构建良好。但是，我遇到了以下错误：
[root@cet7 ~]# java -jar "/root/NetBeansProjects/Switchclient/target/Switchclient-1.0-SNAPSHOT.jar"
Exception in thread "main" java.lang.NoClassDefFoundError: javax/websocket/ContainerProvider
at org.sample.switchclient.Switchclient.main(Switchclient.java:21)
Caused by: java.lang.ClassNotFoundException: javax.websocket.ContainerProvider
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 1 more
[root@cet7 ~]# java -version
java version "1.8.0_65"
Java(TM) SE Runtime Environment (build 1.8.0_65-b17)
Java HotSpot(TM) 64-Bit Server VM (build 25.65-b01, mixed mode)
我做了更多搜索，发现根据Oracle文档，API的“容器实现的完全限定类名ContainerProvider必须列在实现JAR文件的META-INF/services/javax.websocket.ContainerProvider文件中”。ServiceLoader因此，我将serviceloader-maven-plugin添加到 pom.xml 中。结果确实生成了META-INF/services/javax.websocket.ContainerProvider文件，但是没有任何内容，并且运行时错误继续存在。我尝试手动修改下面的内容并将其重新打包到 JAR 中，但没有奏效：
- org.glassfish.tyrus.container.inmemory.InMemoryContainerProvider
- org.glassfish.tyrus.client.ClientManager
我附上了 Java 文件和pom.xml。我已经工作了几个小时并且不知道问题出在哪里，所以对这个线程的任何回复将不胜感激。
非常感谢。
===========LIST1：pom.xml===========
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.sample</groupId>
<artifactId>Switchclient</artifactId>
<version>1.0-SNAPSHOT</version>
<packaging>jar</packaging>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.6</version>
<configuration>
<archive>
<manifest>
<addClasspath>true</addClasspath>
<mainClass>org.sample.switchclient.Switchclient</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>eu.somatik.serviceloader-maven-plugin</groupId>
<artifactId>serviceloader-maven-plugin</artifactId>
<version>1.0.6</version>
<configuration>
<services>
<param>javax.websocket.ContainerProvider</param>
</services>
</configuration>
<executions>
<execution>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>org.glassfish.tyrus.bundles</groupId>
<artifactId>tyrus-standalone-client-jdk</artifactId>
<version>1.12</version>
</dependency>
</dependencies>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
</properties>
</project>
===========LIST2: Switchclient.java===========
package org.sample.switchclient;
import java.net.URI;
import javax.websocket.ClientEndpoint;
import javax.websocket.ContainerProvider;
import javax.websocket.OnMessage;
import javax.websocket.Session;
import javax.websocket.WebSocketContainer;
@ClientEndpoint
public class Switchclient {
@OnMessage
public void onRemoteMessage (String message) {
System.out.println("Received msg: "+message);
}
public static void main(String[] args) {
WebSocketContainer container = null;
Session session = null;
try{
container = ContainerProvider.getWebSocketContainer();
session = container.connectToServer (Switchclient.class, URI.create("ws://localhost:8080/Switchserver/"));
}catch (Exception e) {
e.printStackTrace();
}
}
}