Hadoop has dependencies on Jetty, and jetty will in turn try to include a servlet API
故在hadoop的有些jar包(如hadoop-core,hadoop-common)中,已经包含了一些servlet类,这些类会和Tomcat 的Servlet类发生冲突。若想引用这些Hadoop API,需要在Maven中的hadoop dependency里添加</exclusions>,将这些servlet去除
例如,引用(hadoop-core和hadoop-common)的maven方法
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-core</artifactId>
<version>2.0.0-mr1-cdh4.0.1</version>
<exclusions>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-util</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jsp-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jsp-api-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>servlet-api-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
</exclusion>
<exclusion>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
</exclusion>
<exclusion>
<groupId>tomcat</groupId>
<artifactId>jasper-compiler</artifactId>
</exclusion>
<exclusion>
<groupId>tomcat</groupId>
<artifactId>jasper-runtime</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.0.0-cdh4.0.0</version>
<exclusions>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jetty-util</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jsp-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>jsp-api-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>org.mortbay.jetty</groupId>
<artifactId>servlet-api-2.1</artifactId>
</exclusion>
<exclusion>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
</exclusion>
<exclusion>
<groupId>javax.servlet.jsp</groupId>
<artifactId>jsp-api</artifactId>
</exclusion>
<exclusion>
<groupId>tomcat</groupId>
<artifactId>jasper-compiler</artifactId>
</exclusion>
<exclusion>
<groupId>tomcat</groupId>
<artifactId>jasper-runtime</artifactId>
</exclusion>
</exclusions>
</dependency> 复制代码