刚开始使用spring去写一个关于hdfs的web项目，使用EL表达式时报如下错误：

org.apache.jasper.JasperException: Unable to compile class for JSP: An error occurred at line: 20 in the jsp file: /WEB-INF/jsp/ls.jsp
The method proprietaryEvaluate(String, Class, PageContext, ProtectedFunctionMapper, boolean) in the type PageContextImpl is not applicable for the arguments (String, Class<String>, PageContext, null)<c:forEach var="file" items="${file}"><tr><td>${file.fileName}</td><td>${file.fileSize}</td>     </tr>

</c:forEach>

一个很简单的EL表达式，但是不能编译。因为是初学，还以为代码错误，但是在另一个页面测试一个绝对路径时也出错，才发现是jar包冲突的原因。

maven  pop.xml 修改如下：

<dependency>
<groupId>org.apache.Hadoop</groupId>
<artifactId>hadoop-client</artifactId>
<version>2.6.0</version>
<exclusions>
<exclusion>
<artifactId>servlet-api</artifactId>
<groupId>javax.servlet</groupId>
</exclusion>
<exclusion>
<artifactId>jetty</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jetty-util</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-core</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-json</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-server</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
</exclusions>
</dependency>

<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-common</artifactId>
<version>2.6.0</version>
<exclusions>
<exclusion>
<artifactId>jsp-2.1</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jsp-api</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jetty</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jetty-util</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jasper-runtime</artifactId>
<groupId>tomcat</groupId>
</exclusion>
<exclusion>
<artifactId>jasper-compiler</artifactId>
<groupId>tomcat</groupId>
</exclusion>
<exclusion>
<artifactId>commons-cli</artifactId>
<groupId>commons-cli</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-core</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-json</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-server</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
</exclusions>
</dependency>

<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-hdfs</artifactId>
<version>2.6.0</version>
<exclusions>
<exclusion>
<artifactId>servlet-api</artifactId>
<groupId>javax.servlet</groupId>
</exclusion>
<exclusion>
<artifactId>jetty</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jetty-util</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-core</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-json</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
<exclusion>
<artifactId>jersey-server</artifactId>
<groupId>com.sun.jersey</groupId>
</exclusion>
   <exclusion>
<artifactId>jasper-runtime</artifactId>
<groupId>tomcat</groupId>
</exclusion>
<exclusion>
<artifactId>jsp-api-2.1</artifactId>
<groupId>org.mortbay.jetty</groupId>
</exclusion>
</exclusions>
</dependency>

网上的一些文章只是去除了 hadoop-common 和hadoop-hdfs中的，最开始我只是按照网上的去去除jar包，但是发现还是报错，项目中还是有冲突的jar包，于是在 dependency hierarchy 中查找依赖，发现hadoop-client中也有。去除后成功。