java.lang.SecurityException: class "javax.servlet.FilterRegistration"'

Exception in thread "main" java.lang.SecurityException: class "javax.servlet.FilterRegistration"'s signer information does not match signer information of other classes in the same package

這是一個jar包衝突引起的Java程式錯誤，而且是runtime的錯誤，編譯的時候不出錯，一運行起來就掛。

Exception in thread "main" java.lang.SecurityException: class "javax.servlet.FilterRegistration"'s signer information does not match signer information of other classes in the same package
at java.lang.ClassLoader.checkCerts(ClassLoader.java:898)
at java.lang.ClassLoader.preDefineClass(ClassLoader.java:668)
at java.lang.ClassLoader.defineClass(ClassLoader.java:761)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.spark-project.jetty.servlet.ServletContextHandler.<init>(ServletContextHandler.java:136)
at org.spark-project.jetty.servlet.ServletContextHandler.<init>(ServletContextHandler.java:129)
at org.spark-project.jetty.servlet.ServletContextHandler.<init>(ServletContextHandler.java:98)
at org.apache.spark.ui.JettyUtils$.createServletHandler(JettyUtils.scala:126)
at org.apache.spark.ui.JettyUtils$.createServletHandler(JettyUtils.scala:113)
at org.apache.spark.ui.WebUI.attachPage(WebUI.scala:78)
at org.apache.spark.ui.WebUI$$anonfun$attachTab$1.apply(WebUI.scala:62)
at org.apache.spark.ui.WebUI$$anonfun$attachTab$1.apply(WebUI.scala:62)
at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
at org.apache.spark.ui.WebUI.attachTab(WebUI.scala:62)
at org.apache.spark.ui.SparkUI.initialize(SparkUI.scala:63)
at org.apache.spark.ui.SparkUI.<init>(SparkUI.scala:76)
at org.apache.spark.ui.SparkUI$.create(SparkUI.scala:195)
at org.apache.spark.ui.SparkUI$.createLiveUI(SparkUI.scala:146)
at org.apache.spark.SparkContext.<init>(SparkContext.scala:473)
at com.huawei.SimpleApp$delayedInit$body.apply(SimpleApp.scala:12)
at scala.Function0$class.apply$mcV$sp(Function0.scala:40)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:12)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.App$$anonfun$main$1.apply(App.scala:71)
at scala.collection.immutable.List.foreach(List.scala:318)
at scala.collection.generic.TraversableForwarder$class.foreach(TraversableForwarder.scala:32)
at scala.App$class.main(App.scala:71)
at com.huawei.SimpleApp$.main(SimpleApp.scala:9)
at com.huawei.SimpleApp.main(SimpleApp.scala)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)

網上一搜就知道，這是jar包衝突引起的，也就是說，classpath中的兩個版本不同的jar包都含有FilterRegistration類的實現，並且它們不相容。

在IntelliJ IDEA中使用“Go to class”功能（快速鍵 Ctrl+N），在裡面輸入“FilterRegistration”，可以快速定位到這個類，從而得知它所在的jar包是

package javax.servlet;import java.util.*;/** * Interface through which a {@link Filter} may be further configured. * * @since Servlet 3.0 */public interface FilterRegistration extends Registration {

我並沒有引入javax.servlet這個包,那為什麼會產生衝突呢。雖然你的pom.xml檔案（Maven的工程）裡只包含有一個javax-servlet-api的依賴，但是有其他的jar包會間接依賴於其他版本的 servlet-api，從而可能會產生衝突。

<dependency>    <groupId>org.apache.hadoop</groupId>    <artifactId>hadoop-client</artifactId>    <version>${hadoop.version}</version>    <exclusions>        <exclusion>            <groupId>javax.servlet</groupId>            <artifactId>*</artifactId>        </exclusion>    </exclusions></dependency>

解決方案就是排除servlet所有依賴.

真TM吐血