我刚接触SCXML,甚至无法启动最简单的应用程序。当我尝试启动它时,我会收到以下异常。但是我已经将库commons-scxml-0.9.jar
和该类放在了类路径上。有任何想法吗?
Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/jexl/JexlContext
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631)
at java.lang.ClassLoader.defineClass(ClassLoader.java:615)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:283)
at java.net.URLClassLoader.access$000(URLClassLoader.java:58)
at java.net.URLClassLoader$1.run(URLClassLoader.java:197)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
at org.apache.commons.scxml.env.AbstractStateMachine.<init>(AbstractStateMachine.java:103)
at main.StateMachineImpl.<init>(StateMachineImpl.java:8)
at main.Main.main(Main.java:6)
Caused by: java.lang.ClassNotFoundException: org.apache.commons.jexl.JexlContext
at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
... 15 more
这里是代码:
主类
public class Main {
public static void main(String[] args) {
StateMachineImpl stateMachineImpl = new StateMachineImpl();
stateMachineImpl.fireEvent(Event.START.getEvent());
stateMachineImpl.fireEvent(Event.STOP.getEvent());
}
}
事件
public enum Event {
START("event.start"), STOP("event.stop");
private String event;
private Event(String event) {
this.event = event;
}
public String getEvent() {
return event;
}
public void setEvent(String event) {
this.event = event;
}
}
StateMachineImpl
public class StateMachineImpl extends AbstractStateMachine {
public StateMachineImpl() {
super(StateMachineImpl.class.getClassLoader().getResource("state-machine-cfg.xml"));
}
public void off() {
System.out.println("StateMachine is OFF");
}
public void running() {
System.out.println("StateMachine is RUNNING");
}
}
state-machine-cfg.xml
<?xml version="1.0" encoding="UTF-8"?>
<scxml xmlns="http://www.w3.org/2005/07/scxml" version="1.0"
initialstate="off">
<state id="off">
<transition event="event.start" target="running" />
</state>
<state id="running">
<transition event="event.stop" target="off" />
</state>
</scxml>
编辑 - 解决方案: 我需要添加额外的依赖项(我以为它们会被Maven自动加载)。
pom.xml中的依赖项
<dependency>
<groupId>commons-scxml</groupId>
<artifactId>commons-scxml</artifactId>
<version>0.9</version>
</dependency>
<dependency>
<groupId>commons-logging</groupId>
<artifactId>commons-logging</artifactId>
<version>1.1.1</version>
</dependency>
<dependency>
<groupId>commons-jexl</groupId>
<artifactId>commons-jexl</artifactId>
<version>1.1</version>
</dependency>
<dependency>
<groupId>xalan</groupId>
<artifactId>xalan</artifactId>
<version>2.7.1</version>
</dependency>