Get请求报错406

package com.imooc.reader.controller;
import com.imooc.reader.entity.Category;
import com.imooc.reader.service.CategoryService;
import com.imooc.reader.utils.ResponseUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import java.util.List;

@RestController
@RequestMapping("/api/category")
public class CategoryController {
    @Resource
    private CategoryService categoryService;

    @GetMapping("/list")
    public ResponseUtils list() {
        //标准结构 code = "0"
        ResponseUtils resp = null;
        try {
            List<Category> categories = categoryService.selectAll();
            resp = new ResponseUtils().put("list",categories);
        } catch (Exception e) {
            e.printStackTrace();
            resp = new ResponseUtils(e.getClass().getSimpleName(), e.getMessage());
        }
        return resp;
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:task="http://www.springframework.org/schema/task"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
            http://www.springframework.org/schema/beans
            http://www.springframework.org/schema/beans/spring-beans.xsd
            http://www.springframework.org/schema/context
            http://www.springframework.org/schema/context/spring-context.xsd
            http://www.springframework.org/schema/task
            http://www.springframework.org/schema/task/spring-task.xsd
            http://www.springframework.org/schema/mvc
            http://www.springframework.org/schema/mvc/spring-mvc.xsd
            http://www.springframework.org/schema/tx
            http://www.springframework.org/schema/tx/spring-tx.xsd">
    <context:component-scan base-package="com.imooc.reader"></context:component-scan>
    <mvc:annotation-driven>
        <mvc:message-converters>
            <bean class="org.springframework.http.converter.StringHttpMessageConverter">
                <property name="supportedMediaTypes">
                    <list>
                        <value>application/json;charset=utf-8</value>
                    </list>
                </property>
            </bean>
        </mvc:message-converters>
    </mvc:annotation-driven>
    <mvc:default-servlet-handler/>
    <!--配置数据源（连接那个数据库）-->
    <bean id="dateSource" class="com.alibaba.druid.pool.DruidDataSource">
        <property name="driverClassName" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url"
                  value="jdbc:mysql://localhost:3306/imooc_reader?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=Asia/Shanghai&amp;allowPublicKeyRetrieval=true"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
        <property name="initialSize" value="3"/>
        <property name="maxActive" value="10"/>
    </bean>
    <!--配置sessionFactory-->
<!--    <bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">-->
<!--    更改配置mybatis-plus初始化-->
        <bean id="sessionFactory" class="com.baomidou.mybatisplus.extension.spring.MybatisSqlSessionFactoryBean">
        <property name="dataSource" ref="dateSource"/>
        <property name="mapperLocations" value="classpath:mappers/*.xml"/>
        <property name="configLocation" value="classpath:mybatis-config.xml"/>
<!--            Mybatis-plus 3.4以后版本需要在MyBatisSqlSessionFactory屬性中進行設置-->
        <property name="plugins">
            <array>
                <bean class="com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor">
                    <property name="interceptors">
                        <list>
                            <bean class="com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor"/>
                        </list>
                    </property>
                </bean>
            </array>
        </property>
    </bean>

    <!--配置mapper扫描器-->
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.imooc.reader.mapper"/>
    </bean>
    <bean id="transactionManger" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dateSource"/>
    </bean>
    <tx:annotation-driven transaction-manager="transactionManger"/>
</beans>

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE  configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org./dtd/mybatis-3-config.dtd">
<configuration>
    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>
<!--    MyBatis-plus 3.4版本以前配置分頁插件-->
<!--    <plugins>-->
<!--        <plugin interceptor="com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor"></plugin>-->
<!--    </plugins>-->

</configuration>

同学你好，拼接测试上述贴出代码没有任何问题，如下所示：

这里同学是否按照之前给出的第二点进行排查呢？关于jar包的引入是否正确加载完毕呢？

祝学习愉快~