1、控制台报错信息

严重: Servlet.service() for servlet [jsp] in context with path [/Resource] threw exception [java.lang.ClassCastException: org.apache.catalina.core.DefaultInstanceManager cannot be cast to org.apache.tomcat.InstanceManager] with root cause

java.lang.ClassCastException: org.apache.catalina.core.DefaultInstanceManager cannot be cast to org.apache.tomcat.InstanceManager

2、浏览器报错信息

HTTP Status 500 - java.lang.ClassCastException: org.apache.catalina.core.DefaultInstanceManager cannot be cast to org.apache.tomcat.InstanceManager

3、解决方法

原因是 Tomcat 的 catalina.jar 包冲突了。

网上许多人说是修改 tomcat 中 conf 下的 context.xml 配置文件 在 <context></context> 之间加下面的代码 <Loader delegate="true" />

然而我的修改完后还是不行，于是想着要不更换 apache-tomcat 的版本试一试：（结果还是不行）

[Apache Tomcat 各版本下载]

最后把加上去的代码 <Loader delegate="true" /> 给撤回了，修改了 pom.xml 配置得以解决！！

<?xml version="1.0" encoding="UTF-8"?>

<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>org.xxx.yyy</groupId>

  <artifactId>XXX</artifactId>

  <version>0.0.1-SNAPSHOT</version>

  <packaging>war</packaging>

  <properties>

    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

    <maven.compiler.source>1.8</maven.compiler.source>

    <maven.compiler.target>1.8</maven.compiler.target>

  </properties>

  <dependencies>

    <dependency>

      <groupId>junit</groupId>

      <artifactId>junit</artifactId>

      <version>4.11</version>

      <scope>test</scope>

    </dependency>

  </dependencies>

  <build>

    <finalName>XXX</finalName>

    <pluginManagement>

      <plugins>

        <plugin>

          <artifactId>maven-clean-plugin</artifactId>

          <version>3.0.0</version>

        </plugin>

        <plugin>

          <artifactId>maven-resources-plugin</artifactId>

          <version>3.0.2</version>

        </plugin>

        <plugin>

          <artifactId>maven-compiler-plugin</artifactId>

          <version>3.7.0</version>

        </plugin>

        <plugin>

          <artifactId>maven-surefire-plugin</artifactId>

          <version>2.20.1</version>

        </plugin>

        <plugin>

          <artifactId>maven-war-plugin</artifactId>

          <version>3.2.0</version>

        </plugin>

        <plugin>

          <artifactId>maven-install-plugin</artifactId>

          <version>2.5.2</version>

        </plugin>

        <plugin>

          <artifactId>maven-deploy-plugin</artifactId>

          <version>2.8.2</version>

        </plugin>

        <!-- 配置 tomcat7-maven-plugin 插件 -->

        <plugin>

          <groupId>org.apache.tomcat.maven</groupId>

          <artifactId>tomcat7-maven-plugin</artifactId>

          <version>2.2</version>

          <configuration>

            <server>tomcat7</server>

            <username>xxxx</username>

            <password>xxxx</password>

            <uriEncoding>UTF-8</uriEncoding>

            <url>http://localhost:8080/manager/text</url>

          </configuration>

        </plugin>

      </plugins>

    </pluginManagement>

  </build>

</project>