解决办法：
因为tomcat也有servlet的jar包，所以把pom.xml的servlet-api的jar范围改为provided。
<!-- servlet-api -->
<dependency>
<groupId>javax.servlet</groupId>
<artifactId>servlet-api</artifactId>
<version>2.5</version>
<scope>provided</scope>
</dependency>
详细原因请参考：https://blog.csdn.net/wenguang_hz/article/details/46227275
以下附异常信息
java.lang.ClassCastException: org.springframework.web.filter.CharacterEncodingFilter cannot be cast to javax.servlet.Filter
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(Applicatio
nFilterConfig.java:275)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(Applica
tionFilterConfig.java:422)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFi
lterConfig.java:115)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.
java:4001)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4
651)
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(AbstractRunMo
jo.java:558)
at org.codehaus.mojo.tomcat.AbstractRunMojo.execute(AbstractRunMojo.java
:255)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(Default
BuildPluginManager.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.buildProje
ct(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProje
ct(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThre
adedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(Lifecycl
eStarter.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:584)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:213)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:157)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.
java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAcces
sorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Laun
cher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.jav
a:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(La
uncher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:
356)