java.lang.NoClassDefFoundError:com/fasterxml/jackson/core/util/DefaultIndenter

我是spring框架的新手。我正在尝试使用Maven。我只想在项目运行时打开一个索引页，但无法执行此操作

错误为java.lang.NoClassDefFoundError:com/fasterxml/jackson/core/util/DefaultIndenter

父对象的pom.xml

<dependencyManagement>
    <dependencies>
        <dependency>
            <groupId>javax</groupId>
            <artifactId>javaee-web-api</artifactId>
            <version>7.0</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>4.3.12.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>4.3.12.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>6.0.6</version>
        </dependency>

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>2.9.2</version>
        </dependency>

        <dependency>
            <groupId>com.nishan</groupId>
            <artifactId>LifeStyle</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
</dependencyManagement>

---

根据

元素的文档（重点）：

“继承自此项目的项目的默认依赖项信息本节中的依赖项不会立即解决。相反，当从该POM派生的POM声明由匹配的groupId和artifactId描述的依赖项时，如果尚未指定版本和本节中的其他值，则会将其用于该依赖项。”

---

换句话说，您可能在模块POM中缺少正确的

定义。

找到包含该类的JAR并将其添加到Maven POM.xml中。如果您发现Maven确实包含该JAR，请检查您的包，以查看该JAR是否在运行时出现在包中。

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

<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
     version="3.1">

    <servlet>
        <servlet-name>dispatcher</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>dispatcher</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <session-config>
        <session-timeout>
            30
        </session-timeout>
    </session-config>
</web-app>

    <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:p="http://www.springframework.org/schema/p"

       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.3.xsd
          http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
          http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
">

    <context:component-scan base-package="com.nishan.webmodule"/>
    <mvc:annotation-driven/>
    <mvc:resources mapping="/static/**" location="/WEB-INF/assets"/>

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"
    p:prefix="/WEB-INF/views/" p:suffix=".jsp"/>

</beans>

   @Controller
@RequestMapping(value="/")
public class DefaultServlet {

    @RequestMapping(method=RequestMethod.GET)
    public String index() {
        return "index";
    }
}