原因：java.lang.ClassNotFoundException:com.mongodb.ReadPreference

添加了mongodb java驱动程序bust的依赖项，但仍然会出现以下异常：-

Caused by: java.lang.ClassNotFoundException: com.mongodb.ReadPreference
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1702)
    at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1547)

pom.xml中的依赖项如下-

 <dependency>
      <groupId>org.mongodb</groupId>
      <artifactId>mongo-java-driver</artifactId>
      <version>2.11.3</version>
    </dependency>

org.mongodb
mongo java驱动程序
2.11.3

完整的pom.xml文件是-

<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>EmpCYC_AM</groupId>
  <artifactId>EmpCYC_AM</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <name>Emp</name>
  <description>Spring_Angular_Mongo</description>
  <dependencies>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-annotations-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-catalina</artifactId>
      <version>7.0.47</version>
      <scope>provided</scope>
    </dependency>  
    <dependency>
        <groupId>org.apache.tomcat</groupId>
        <artifactId>catalina</artifactId>
        <version>6.0.26</version>
    </dependency>

    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-el-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jasper-el</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jasper</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-jsp-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-servlet-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-dbcp</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat7-websocket</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>org.apache.tomcat</groupId>
      <artifactId>tomcat-websocket-api</artifactId>
      <version>7.0.47</version>
    </dependency>
    <dependency>
      <groupId>c3p0</groupId>
      <artifactId>c3p0</artifactId>
      <version>0.9.1.2</version>
    </dependency>
    <dependency>
      <groupId>commons-beanutils</groupId>
      <artifactId>commons-beanutils</artifactId>
      <version>1.8.0</version>
    </dependency>
    <dependency>
      <groupId>commons-collections</groupId>
      <artifactId>commons-collections</artifactId>
      <version>3.1</version>
    </dependency>
    <dependency>
      <groupId>commons-digester</groupId>
      <artifactId>commons-digester</artifactId>
      <version>2.0</version>
    </dependency>
    <dependency>
      <groupId>commons-io</groupId>
      <artifactId>commons-io</artifactId>
      <version>1.3.2</version>
    </dependency>
    <dependency>
      <groupId>commons-lang</groupId>
      <artifactId>commons-lang</artifactId>
      <version>2.4</version>
    </dependency>
    <dependency>
      <groupId>commons-logging</groupId>
      <artifactId>commons-logging</artifactId>
      <version>1.1.1</version>
    </dependency>
    <dependency>
      <groupId>dom4j</groupId>
      <artifactId>dom4j</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.directwebremoting</groupId>
      <artifactId>dwr</artifactId>
      <version>2.0.3</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>2.0.0</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>2.0.0</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>2.0.0</version>
    </dependency>
    <dependency>
      <groupId>org.codehaus.jackson</groupId>
      <artifactId>jackson-mapper-asl</artifactId>
      <version>1.7.1</version>
    </dependency>
    <dependency>
      <groupId>javassist</groupId>
      <artifactId>javassist</artifactId>
      <version>3.12.0.GA</version>
    </dependency>
    <dependency>
      <groupId>org.mortbay.jetty</groupId>
      <artifactId>servlet-api-2.5</artifactId>
      <version>6.1.2rc1</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>javax.servlet.jsp.jstl</groupId>
      <artifactId>jstl-api</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>1.2.12</version>
    </dependency>
    <dependency>
      <groupId>org.mongodb</groupId>
      <artifactId>mongo-java-driver</artifactId>
      <version>2.11.3</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>1.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>1.6.1</version>
    </dependency>
       <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-commons-core</artifactId>
      <version>1.2.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-orm</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.0.0.RELEASE</version>
    </dependency>
    <dependency>
      <groupId>javassist</groupId>
      <artifactId>javassist</artifactId>
      <version>3.12.0.GA</version>
    </dependency>
    <dependency>
      <groupId>org.mongodb</groupId>
      <artifactId>mongo-java-driver</artifactId>
      <version>2.6.5</version>
    </dependency>
    <dependency>
      <groupId>org.springframework.data</groupId>
      <artifactId>spring-data-commons-core</artifactId>
      <version>1.2.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjrt</artifactId>
        <version>1.7.3</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-mongodb</artifactId>
        <version>1.0.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.aspectj</groupId>
        <artifactId>aspectjweaver</artifactId>
        <version>1.8.6</version>
    </dependency>
    <dependency>
   <groupId>javax.persistence</groupId>
       <artifactId>persistence-api</artifactId>
       <version>1.0.2</version>
       <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.apache.tomcat.maven</groupId>
        <artifactId>tomcat7-maven-plugin</artifactId>
        <version>2.0-beta-1</version>
        <type>maven-plugin</type>
        <scope>provided</scope>
    </dependency>
  </dependencies>
  <build>
    <sourceDirectory>src</sourceDirectory>
    <resources>
      <resource>
        <directory>src</directory>
        <excludes>
          <exclude>**/*.java</exclude>
        </excludes>
      </resource>
    </resources>
    <plugins>
        <plugin>
          <groupId>org.apache.tomcat.maven</groupId>
          <artifactId>tomcat6-maven-plugin</artifactId>
          <version>2.0-beta-1</version>
        </plugin>
        <plugin>
          <groupId>org.apache.tomcat.maven</groupId>
          <artifactId>tomcat7-maven-plugin</artifactId>
          <version>2.0-beta-1</version>
      </plugin>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.1</version>
        <configuration>
          <source>1.6</source>
          <target>1.6</target>
        </configuration>
      </plugin>
      <plugin>
        <artifactId>maven-war-plugin</artifactId>
        <version>2.3</version>
        <configuration>
          <warSourceDirectory>WebContent</warSourceDirectory>
          <failOnMissingWebXml>false</failOnMissingWebXml>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

4.0.0
恩普西科姆酒店
恩普西科姆酒店
0.0.1-快照
战争
电磁脉冲
弹簧(角度)(角度)蒙戈(Mongo)
org.apache.tomcat
tomcat注释api
7.0.47
org.apache.tomcat
卡塔琳娜雄猫
7.0.47
假如
org.apache.tomcat
卡塔琳娜
6.0.26
org.apache.tomcat
tomcat el api
7.0.47
org.apache.tomcat
雄猫贾斯珀
7.0.47
org.apache.tomcat
雄猫贾斯珀
7.0.47
org.apache.tomcat
tomcat jsp api
7.0.47
org.apache.tomcat
TomcatServletAPI
7.0.47
org.apache.tomcat
TomcatAPI
7.0.47
org.apache.tomcat
TomcatDBCP
7.0.47
org.apache.tomcat
tomcat7 websocket
7.0.47
org.apache.tomcat
tomcat websocket api
7.0.47
c3p0
c3p0
0.9.1.2
公地小海狸
公地小海狸
1.8.0
公地收藏
公地收藏
3.1
公地蒸煮器
公地蒸煮器
2
公地io
公地io
1.3.2
公地郎
公地郎
2.4
公用记录
公用记录
1.1.1
dom4j
dom4j
1.6.1
org.directwebremoting
dwr
2.0.3
com.fasterxml.jackson.core
杰克逊注释
2.0.0
com.fasterxml.jackson.core
杰克逊核心
2.0.0
com.fasterxml.jackson.core
杰克逊数据绑定
2.0.0
org.codehaus.jackson
杰克逊地图绘制者
1.7.1
javassist
javassist
3.12.0.GA
org.mortbay.jetty
servlet-api-2.5
6.1.2rc1
javax.servlet
jstl
1.2
javax.servlet.jsp.jstl
JSTLAPI
1.2
log4j
log4j
1.2.12
org.mongodb
mongo java驱动程序
2.11.3
org.slf4j
slf4j api
1.6.1
org.slf4j
slf4j-log4j12
1.6.1
org.springframework
春豆
4.0.0.0发布
org.springframework
spring上下文
4.0.0.0发布
org.springframework
弹簧芯
4.0.0.0发布
org.springframework.data
spring数据共享核心
1.2.0.1发布
org.springframework
弹簧式
4.0.0.0发布
org.springframework
春季甲虫
4.0.0.0发布
org.springframework
弹簧网
4.0.0.0发布
org.springframework
SpringWebMVC
4.0.0.0发布
javassist
javassist
3.12.0.GA
org.mongodb
mongo java驱动程序
2.6.5
org.springframework.data
spring数据共享核心
1.2.0.1发布
org.aspectj
aspectjrt
1.7.3
org.springframework.data
spring数据mongodb
1.0.0.1版本
org.aspectj
aspectjweaver
1.8.6
javax.persistence
持久性api
1.0.2
假如
org.apache.tomcat.maven
tomcat7 maven插件
2.0-beta-1
maven插件
假如
src
src
**/*.爪哇
org.apache.tomcat.maven
tomcat6 maven插件
2.0-beta-1
org.apache.tomcat.maven
tomcat7 maven插件
2.0-beta-1
maven编译器插件
3.1
1.6
1.6
maven战争插件
2.3
网络内容
假的

---

如何解决此问题？

mongo java驱动程序有两个依赖项

org.mongodb:mongojava驱动程序：jar->version 2.11.3 vs 2.6.5

---

当同一个类被定义两次时，JVM不知道采取什么并抛出ClassNotFoundException

您添加的依赖项有问题，即：

        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongo-java-driver</artifactId>
            <version>2.11.3</version>
        </dependency> 
        <dependency>
            <groupId>org.mongodb</groupId>
            <artifactId>mongo-java-driver</artifactId>
            <version>2.6.5</version>
        </dependency>

org.mongodb
为什么要更改默认设置，如src文件夹？没有意义…如果您生成war文件，为什么您的项目中有tomcat的依赖项（catalina、jasper等）通常不需要…您是否通过
mvn clean package
检查结果war是否包含所有需要的包？测试首先手动将war部署到tomcat并检查日志…这些依赖项在转换后由向导生成。正确的方法是什么？你能给我指点一下吗？是的，我已经弄明白了，并且已经把它去掉了。谢谢，@sbuisson
Exception in thread "main" java.lang.NoSuchFieldError: ACKNOWLEDGED
    at org.apache.logging.log4j.nosql.appender.mongodb.MongoDbProvider.<clinit>(MongoDbProvider.java:48)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.logging.log4j.core.config.plugins.util.PluginBuilder.build(PluginBuilder.java:132)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createPluginObject(AbstractConfiguration.java:952)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:892)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:884)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.createConfiguration(AbstractConfiguration.java:884)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.doConfigure(AbstractConfiguration.java:508)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.initialize(AbstractConfiguration.java:232)
    at org.apache.logging.log4j.core.config.AbstractConfiguration.start(AbstractConfiguration.java:244)
    at org.apache.logging.log4j.core.LoggerContext.setConfiguration(LoggerContext.java:545)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:617)
    at org.apache.logging.log4j.core.LoggerContext.reconfigure(LoggerContext.java:634)
    at org.apache.logging.log4j.core.LoggerContext.start(LoggerContext.java:229)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:242)
    at org.apache.logging.log4j.core.impl.Log4jContextFactory.getContext(Log4jContextFactory.java:45)
    at org.apache.logging.log4j.LogManager.getContext(LogManager.java:174)
    at org.apache.logging.log4j.LogManager.getLogger(LogManager.java:618)
    at com.ituple.logging.appender.nosql.TestService.<init>(TestService.java:9)
    at com.ituple.logging.appender.nosql.Main.main(Main.java:6)