标签：maven exception tomcat servlet filter
引言： Maven功能强大，但是又有些复杂，难以捉摸和使用。在本人开发中碰到了一个ClassCastException的问题，通过这个问题的解决，加深了对于maven依赖管理中scope的理解。
1. 问题的引入
部署环境tomcat 7， 开发中使用的框架spring,spring data,hibernate之类的，基于Maven部署过程中，会出现以下异常信息：
SEVERE: Exception starting filter Spring OpenEntityManagerInViewFilter java.lang.ClassCastException: org.springframework.orm.jpa.support.OpenEntityManagerInViewFilter cannot be cast to javax.servlet.Filter at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4001) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4651) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardHost.start(StandardHost.java:785) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:445) at org.apache.catalina.startup.Embedded.start(Embedded.java:825) at org.codehaus.mojo.tomcat.AbstractRunMojo.startContainer(AbstractRunMojo.java:558) at org.codehaus.mojo.tomcat.AbstractRunMojo.execute(AbstractRunMojo.java:255) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:582) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214) at org.apache.maven.cli.MavenCli.main(MavenCli.java:158) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) Feb 3, 2015 1:36:32 PM org.apache.catalina.core.StandardContext filterStart SEVERE: Exception starting filter Set Character Encoding java.lang.ClassCastException: org.springframework.web.filter.CharacterEncodingFilter cannot be cast to javax.servlet.Filter at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4001) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4651) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardHost.start(StandardHost.java:785) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:445) at org.apache.catalina.startup.Embedded.start(Embedded.java:825) at org.codehaus.mojo.tomcat.AbstractRunMojo.startContainer(AbstractRunMojo.java:558) at org.codehaus.mojo.tomcat.AbstractRunMojo.execute(AbstractRunMojo.java:255) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:582) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214) at org.apache.maven.cli.MavenCli.main(MavenCli.java:158) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) Feb 3, 2015 1:36:32 PM org.apache.catalina.core.StandardContext filterStart SEVERE: Exception starting filter HiddenHttpMethodFilter java.lang.ClassCastException: org.springframework.web.filter.HiddenHttpMethodFilter cannot be cast to javax.servlet.Filter at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:275) at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422) at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115) at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4001) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4651) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardHost.start(StandardHost.java:785) at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045) at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:445) at org.apache.catalina.startup.Embedded.start(Embedded.java:825) at org.codehaus.mojo.tomcat.AbstractRunMojo.startContainer(AbstractRunMojo.java:558) at org.codehaus.mojo.tomcat.AbstractRunMojo.execute(AbstractRunMojo.java:255) at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153) at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116) at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80) at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51) at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120) at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347) at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154) at org.apache.maven.cli.MavenCli.execute(MavenCli.java:582) at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214) at org.apache.maven.cli.MavenCli.main(MavenCli.java:158) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289) at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229) at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415) at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356) Feb 3, 2015 1:36:32 PM org.apache.catalina.core.StandardContext start SEVERE: Error filterStart Feb 3, 2015 1:36:32 PM org.apache.catalina.core.StandardContext start SEVERE: Context [/bsettle] startup failed due to previous errors
2. 问题分析
这几个Servlet都是在web.xml中配置的Filter，其配置没有问题。错误类型为ClassCastException, 就是其实现的Filter与目标的Filter存在不同，就是说有可能是类库引用的不同，导致在启动过程中，出现这样的问题。
3. 查看pom.xml
在开发中，引入了如下包，用以解决Servlet/JSP中常用类库的引用问题，这些都是在Web服务器中实现的类库。
<dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-servlet-api</artifactId> <version>7.0.56</version> </dependency> <dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-jsp-api</artifactId> <version>7.0.57</version> </dependency>这里可以看到，jsp/servlet将在整个的打包部署声明周期中被用到，并被打包到部署环境中。
4. 问题的解决
由于无法预知最终部署的Web服务器的版本和类型，故这里的这两个依赖在编译、测试中会用到，但是在部署环境中，是不能打包到部署环境中去的。
故需要做如下修改：
<dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-servlet-api</artifactId> <version>7.0.56</version> <scope>provided</scope> </dependency> <dependency> <groupId>org.apache.tomcat</groupId> <artifactId>tomcat-jsp-api</artifactId> <version>7.0.57</version> <scope>provided</scope> </dependency>
5. Scope的含义和使用
<dependency>中<scope>，它主要管理依赖的部署。目前<scope>可以使用5个值：
* compile，缺省值，适用于所有阶段，会随着项目一起发布。
* provided，类似compile，期望JDK、容器或使用者会提供这个依赖。如servlet.jar。
* runtime，只在运行时使用，如JDBC驱动，适用运行和测试阶段。
* test，只在测试时使用，用于编译和运行测试代码。不会随项目发布。
* system，类似provided，需要显式提供包含依赖的jar，Maven不会在Repository中查找它。
| 依赖范围（scope） | 主源码classpath可用 | 测试源码classpath可用 | 会被打包 |
| compile 缺省值 | TRUE | TRUE | TRUE |
| test | FALSE | TRUE | FALSE |
| runtime | FALSE | TRUE | TRUE |
| provided | TRUE | TRUE | FALSE |
Maven部署过程中的ClassCastException问题
标签：maven exception tomcat servlet filter
原文地址：http://blog.csdn.net/blueheart20/article/details/43448693
