java.lang.NoClassDefFoundError : javax/el/ELManager

Question

我正在使用 Spring Tool Suite 在 Spring 中开发一个 Web 应用程序。如果我使用 IDE 构建应用程序并将其部署到提供的 Pivotal tc 服务器上，它就可以正常工作。但是，如果我执行手动“mvn clean package”构建并尝试将其部署到独立的 Tomcat 服务器(使用最新的 Tomcat 7)，则会引发以下异常:

2017-08-23 15:24:13 WARN  AnnotationConfigWebApplicationContext:551 - Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerAdapter' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcValidator' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: javax/el/ELManager
2017-08-23 15:24:13 ERROR DispatcherServlet:502 - Context initialization failed
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'requestMappingHandlerAdapter' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter]: Factory method 'requestMappingHandlerAdapter' threw exception; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mvcValidator' defined in org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration: Invocation of init method failed; nested exception is java.lang.NoClassDefFoundError: javax/el/ELManager

经过进一步检查，它确实提示上面几行没有加载 jar :

sie 23, 2017 3:24:12 PM org.apache.catalina.startup.HostConfig deployWAR
INFO: Deploying web application archive D:\Apache-Tomcat-7.0\webapps\TestApp-0.0.1-SNAPSHOT.war
sie 23, 2017 3:24:12 PM org.apache.catalina.loader.WebappClassLoader validateJarFile
INFO: validateJarFile(D:\Apache-Tomcat-7.0\webapps\TestApp-0.0.1-SNAPSHOT\WEB-INF\lib\el-api-2.2.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/el/Expression.class
sie 23, 2017 3:24:12 PM org.apache.catalina.loader.WebappClassLoader validateJarFile
INFO: validateJarFile(D:\Apache-Tomcat-7.0\webapps\TestApp-0.0.1-SNAPSHOT\WEB-INF\lib\javax.servlet-api-3.1.0.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/servlet/Servlet.class
sie 23, 2017 3:24:12 PM org.apache.catalina.loader.WebappClassLoader validateJarFile
INFO: validateJarFile(D:\Apache-Tomcat-7.0\webapps\TestApp-0.0.1-SNAPSHOT\WEB-INF\lib\tomcat-el-api-8.0.21.jar) - jar not loaded. See Servlet Spec 2.3, section 9.7.2. Offending class: javax/el/Expression.class
2017-08-23 15:24:13 INFO  ContextLoader:304 - Root WebApplicationContext: initialization started

我的pom.xml:

<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>com.exmaple.mvc</groupId>
  <artifactId>TestApp</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>war</packaging>
  <dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.3.10.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.3.10.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.3.10.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-test</artifactId>
        <version>4.3.10.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>slf4j-log4j12</artifactId>
        <version>1.6.6</version>
    </dependency>
    <dependency>
       <groupId>log4j</groupId>
       <artifactId>log4j</artifactId>
       <version>1.2.17</version>
       <exclusions>
        <exclusion>
            <artifactId>jms</artifactId>
            <groupId>javax.jms</groupId>
        </exclusion>
        <exclusion>
            <artifactId>jmxri</artifactId>
            <groupId>com.sun.jmx</groupId>
        </exclusion>
        <exclusion>
            <artifactId>jmxtools</artifactId>
            <groupId>com.sun.jdmk</groupId>
            </exclusion>
        </exclusions>
    </dependency>
        <dependency>
        <groupId>jstl</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.mockito/mockito-all -->
    <dependency>
        <groupId>org.mockito</groupId>
        <artifactId>mockito-all</artifactId>
        <version>1.9.5</version>
        <scope>test</scope>
    </dependency>
    <!-- https://mvnrepository.com/artifact/commons-lang/commons-lang -->
    <dependency>
        <groupId>commons-lang</groupId>
        <artifactId>commons-lang</artifactId>
        <version>2.3</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.hibernate/hibernate-validator -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>6.0.1.Final</version>
    </dependency>

    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
    </dependency>
  </dependencies>

    <build>
        <plugins>
            <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
            </configuration>
        </plugin>
        </plugins>
    </build>

</project>

此行为的原因是什么以及如何解决此问题？

编辑更多信息:

添加<scope>provided</scope>至javax.servlet-api似乎修复了有关 javax.servlet-api 的警告没有在开始时加载。问题 el-api仍然存在。

我检查了 tomcat/lib 目录，它已经包含 el-api.jar其中，这可能就是为什么它告诉我它不会加载我在 pom.xml 中列出的内容。问题是，添加 <scope>provided</scope>也没有修复它。无论我做什么，它仍然提示给我同样的java.lang.NoClassDefFoundError: javax/el/ELManager错误。

解决方案

除了上面编辑中有关 javax.servlet-api 的部分之外el-api 的问题是我正在运行 Tomcat 7，并提供 el-api 2.2 版本中的 jar。 el-api 3.0 中引入了缺失的类。在 Tomcat 8(带有 el-api 3.0 jar)中运行相同的 web 应用程序可以正常工作。

Answer 1

您错过了 javax.el-api 作为依赖项。添加:

<dependency>
    <groupId>javax.el</groupId>
    <artifactId>javax.el-api</artifactId>
    <version>3.0.0</version>
</dependency>

到你的pom.xml