Java eclipse activiti中的BPMN示例错误

我按照activiti用户指南安装activiti并创建示例VacationRequestBPMN项目。当我运行这个项目时，我不断地得到这个关于进程引擎创建的错误

exception in thread "main" java.lang.NoClassDefFoundError: org/slf4j/LoggerFactory
    at org.activiti.engine.ProcessEngines.<clinit>(ProcessEngines.java:63)
    at vacation.resources.test.main(test.java:15)
Caused by: java.lang.ClassNotFoundException: org.slf4j.LoggerFactory
    at java.net.URLClassLoader$1.run(URLClassLoader.java:372)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:360)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 2 more

这是我的activiti.cfg.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" 
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans   http://www.springframework.org/schema/beans/spring-beans.xsd">

  <bean id="processEngineConfiguration" class="org.activiti.engine.impl.cfg.StandaloneInMemProcessEngineConfiguration">
    <property name="jdbcUrl" value="jdbc:h2:mem:activiti;DB_CLOSE_DELAY=1000" />
    <property name="jdbcDriver" value="org.h2.Driver" />
    <property name="jdbcUsername" value="sa" />
    <property name="jdbcPassword" value="" />
  </bean>

</beans>

---

我尝试了getDefaultProcessEngine之外的其他选项，但都以错误告终

您的项目是否使用Maven或其他工具进行依赖关系管理？看起来您的项目缺少log4j、logback等记录器实现

尝试添加到项目：

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.10</version>
</dependency>

<dependency>
    <groupId>org.slf4j</groupId>
    <artifactId>slf4j-log4j12</artifactId>
    <version>1.7.10</version>
</dependency>