执行上一个测试用例也没问题，新写了一个报了这个错误，再返回去执行前面没问题的test也开始报这个错

package com.imooc.mybatis.entity;

public class Goods {
    private Integer goodsId;
    private String title;
    private String subTitle;
    private Float originalCost;
    private Float currentPrice;
    private Float discount;
    private Integer isFreeDelivery;
    private Integer categoryId;

    public Integer getGoodsId() {
        return goodsId;
    }

    public void setGoodsId(Integer goodsId) {
        this.goodsId = goodsId;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getSubTitle() {
        return subTitle;
    }

    public void setSubTitle(String subTitle) {
        this.subTitle = subTitle;
    }

    public Float getOrginalCost() {
        return originalCost;
    }

    public void setOrginalCost(Float orginalCost) {
        this.originalCost = orginalCost;
    }

    public Float getCurrentPrice() {
        return currentPrice;
    }

    public void setCurrentPrice(Float currentPrice) {
        this.currentPrice = currentPrice;
    }

    public Float getDiscount() {
        return discount;
    }

    public void setDiscount(Float discount) {
        this.discount = discount;
    }

    public Integer getIsFreeDelivery() {
        return isFreeDelivery;
    }

    public void setIsFreeDelivery(Integer isFreeDelivery) {
        this.isFreeDelivery = isFreeDelivery;
    }

    public Integer getCategoryId() {
        return categoryId;
    }

    public void setCategoryId(Integer categoryId) {
        this.categoryId = categoryId;
    }
}

package com.imooc.mybatis.utils;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import java.io.IOException;
import java.io.Reader;

public class MyBatisUtils {
    private static SqlSessionFactory sqlSessionFactory = null;
    static {
        Reader reader= null;
        try {
            reader = Resources.getResourceAsReader("mybatis-config.xml");
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        } catch (IOException e) {
            e.printStackTrace();
            throw new ExceptionInInitializerError(e);
        }
    }
    public static SqlSession openSession(){
        return sqlSessionFactory.openSession();
    }
    public static void closeSession(SqlSession sqlSession){
        if (sqlSession!=null){
            sqlSession.close();
        }
    }
}

package com.imooc.mybatis;

import com.imooc.mybatis.entity.Goods;
import com.imooc.mybatis.utils.MyBatisUtils;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.Reader;
import java.sql.Connection;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MyBatisTestor {
    @Test
    public void testSqlSessionFactory() throws IOException {
        Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
        System.out.println("SessionFactory加载成功！");

        SqlSession sqlSession=null;
        try {
            sqlSession = sqlSessionFactory.openSession();
            Connection connection = sqlSession.getConnection();
            System.out.println(connection);
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (sqlSession!=null){
                sqlSession.close();
            }
        }
    }
    @Test
    public void testMybatisUtils(){
        SqlSession sqlSession = MyBatisUtils.openSession();
        Connection connection = sqlSession.getConnection();
        System.out.println(connection);
        MyBatisUtils.closeSession(sqlSession);
    }
    @Test
    public void testSelectAll(){
        SqlSession sqlSession = null;
        try{
            sqlSession=MyBatisUtils.openSession();
            List<Goods> list=sqlSession.selectList("goods.selectAll");
            for (Goods g:list){
                System.out.println(g.getTitle());
            }
        }catch (Exception e){
            throw e;

        }finally {
            MyBatisUtils.closeSession(sqlSession);
        }
    }
    @Test
    public void testSelectById(){
        SqlSession sqlSession = null;
        try{
            sqlSession=MyBatisUtils.openSession();
            Goods goods=sqlSession.selectOne("goods.selectById",1602);
            System.out.println(goods.getTitle());
        }catch (Exception e){
            throw e;
        }finally {
            MyBatisUtils.closeSession(sqlSession);
        }
    }
    @Test
    public void testSelectByPriceRange(){
        SqlSession sqlSession = null;
        try{
            sqlSession=MyBatisUtils.openSession();
            Map param = new HashMap();
            param.put("min",100);
            param.put("max",500);
            param.put("lmit",10);
            List<Goods> list=sqlSession.selectList("selectByPriceRange",param);
            for (Goods goods:list){
                System.out.println(goods.getTitle()+":"+ goods.getCurrentPrice());
            }

        }catch (Exception e){
            throw e;
        }finally {
            MyBatisUtils.closeSession(sqlSession);

        }
    }
}

相关代码：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="goods">
    <select id="selectAll" resultType="com.imooc.mybatis.entity.Goods">
        select * from t_goods order by goods_id desc limit 10
    </select>
    <select id="selectById" parameterType="Integer" resultType="com.imooc.mybatis.entity.Goods">
        select * from t_goods where goods_id = #{value}
    </select>
    <select id="selectByPriceRange" parameterType="java.util.map" resultType="com.imooc.mybatis.entity.Goods">
        select * from t_goods where current_price between #{min} and #{max} order by current_price limit 0,#{limt}
    </select>
</mapper>

相关代码：

<?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>
    <!--设置默认指向的数据库-->
    <environments default="dev">
        <!--配置环境，不同的环境不同的id名字-->
        <environment id="dev">
<!--            采用JDBC方式进行数据库事务管理-->
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/babytun?useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>

        </environment>
    </environments>
    <mappers>
        <mapper resource="mappers/goods.xml"></mapper>
    </mappers>
</configuration>