spring mvc json jar 包

<mvc:annotation-driven/>

    <context:component-scan base-package="com.cjy.module" />

    <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
        <property name="messageConverters">
            <list>
                <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter"/>
            </list>
        </property>
    </bean>

    <bean class="org.springframework.web.servlet.mvc.SimpleControllerHandlerAdapter" />
    <bean class="org.springframework.web.servlet.mvc.HttpRequestHandlerAdapter" />