提交报错，没有改代码

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.imooc.oa.dao.EmployeeDao">

   <resultMap id="employee" type="Employee">
       <id property="sn" column="sn" javaType="String"/>
       <result property="password" column="password" javaType="String"/>
       <result property="name" column="name" javaType="String"/>
       <result property="departmentSn" column="department_sn" javaType="String"/>
       <result property="post" column="post" javaType="String"/>
       <association property="department" column="department_sn" javaType="Department" >
           <id property="sn" column="dsn" javaType="String"/>
           <result property="name" column="dname" javaType="String"/>
       </association>
   </resultMap>


   <insert id="insert" parameterType="Employee">
       insert into employee values(#{sn},#{password},#{name},#{departmentSn},#{post})
   </insert>

   <update id="update" parameterType="Employee">
       update employee set name=#{name},password=#{password},department_sn=#{departmentSn},post=#{post} where sn=#{sn}
   </update>

   <delete id="delete" parameterType="String">
       delete from employee where sn=#{sn}
   </delete>

   <select id="select" parameterType="String" resultMap="employee">
       select e.*,d.sn dsn,d.name dname from employee e left join department d on d.sn=e.department_sn
        where e.sn=#{sn}
   </select>

   <select id="selectAll" resultMap="employee">
       select e.*,d.sn dsn,d.name dname from employee e left join department d on d.sn=e.department_sn
   </select>
   <select id="selectByDepartmentAndPost" resultMap="employee">
       select e.*,d.sn dsn,d.name dname from employee e left join department d on d.sn=e.department_sn
       where e.sn is not NULL
       <if test="dsn!=null">
           and e.department_sn=#{dsn}
       </if>
       <if test="post!=null">
           and e.post=#{post}
       </if>
   </select>
</mapper>

package com.imooc.oa.dao;

import com.imooc.oa.entity.Employee;
import org.apache.ibatis.annotations.Param;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository("employeeDao")
public interface EmployeeDao {
   void insert(Employee employee);
   void update(Employee employee);
   void delete(String sn);
   Employee select(String sn);
   List<Employee> selectAll();
   List<Employee> selectByDepartmentAndPost(@Param("dsn") String dsn,@Param("post") String post);
}

你好同学，测试了你的代码是没问题的，出现问题的原因应该是你employee没有返回员工数据，我需要你提供下图标记的两个文件的代码，注意不要将问题粘贴到回复中哦，应该粘贴到回答中，否则会失去代码格式的，祝学习愉快~

package com.imooc.oa.dao;

import com.imooc.oa.entity.ClaimVoucher;
import com.imooc.oa.entity.Employee;
import org.apache.ibatis.annotations.Param;
import org.springframework.stereotype.Repository;

import java.util.List;

@Repository("claimVoucherDao")
public interface ClaimVoucherDao {
   void insert(ClaimVoucher claimVoucher);
   void update(ClaimVoucher claimVoucher);
   void delete(int id);
   ClaimVoucher select(int id);
   List<ClaimVoucher> selectByCreateSn(String csn);
   List<ClaimVoucher> selectByNextDealSn(String ndsn);
}

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.4//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.imooc.oa.dao.ClaimVoucherDao">
   <resultMap id="claimVoucher" type="ClaimVoucher">
       <id property="id" column="id" javaType="int"/>
       <result property="cause" column="cause" javaType="String"/>
       <result property="createSn" column="create_sn" javaType="String"/>
       <result property="createTime" column="create_time" javaType="java.util.Date"/>
       <result property="nextDealSn" column="next_deal_sn" javaType="String"/>
       <result property="totalAmount" column="total_amount" javaType="Double"/>
       <result property="status" column="status" javaType="String"/>
       <association property="creater" column="create_sn" javaType="Employee">
           <result property="name" column="cname" javaType="String"/>
           <result property="post" column="cpost" javaType="String"/>
       </association>
       <association property="dealer" column="next_deal_sn" javaType="Employee">
           <result property="name" column="dname" javaType="String"/>
           <result property="post" column="dpost" javaType="String"/>
       </association>
   </resultMap>

   <insert id="insert" useGeneratedKeys="true" keyProperty="id" parameterType="ClaimVoucher">
       insert into claim_voucher(cause,create_sn,create_time,next_deal_sn,total_amount,status)
       values(#{cause},#{createSn},#{createTime},#{nextDealSn},#{totalAmount},#{status})
   </insert>
   <update id="update" parameterType="ClaimVoucher">
       update claim_voucher set cause=#{cause},next_deal_sn=#{nextDealSn},total_amount=#{totalAmount},status=#{status} where id=#{id}
   </update>
   <delete id="delete" parameterType="Integer">
       delete from claim_voucher where id=#{id}
   </delete>
   <select id="select" resultMap="claimVoucher" parameterType="Integer">
       select cv.*,ce.name cname,ce.post cpost,d.name dname,d.post dpost
       from claim_voucher cv
       left join employee ce on ce.sn=cv.create_sn
       left join employee d on d.sn = cv.next_deal_sn
       where cv.id=#{id}
   </select>
   <select id="selectByCreateSn" resultMap="claimVoucher" parameterType="String">
       select cv.*,ce.name cname,ce.post cpost,d.name dname,d.post dpost
       from claim_voucher cv
       left join employee ce on ce.sn=cv.create_sn
       left join employee d on d.sn = cv.next_deal_sn
       where cv.create_sn=#{csn} order by cv.create_time desc
   </select>
   <select id="selectByNextDealSn" resultMap="claimVoucher" parameterType="String">
       select cv.*,ce.name cname,ce.post cpost,d.name dname,d.post dpost
       from claim_voucher cv
       left join employee ce on ce.sn=cv.create_sn
       left join employee d on d.sn = cv.next_deal_sn
       where cv.next_deal_sn=#{ndsn} order by cv.create_time desc
   </select>
</mapper>

你好同学，建议你不要着急，遇到问题只能一点一点试，这也是教同学如何解决bug的方法，另外同学粘贴一下我下图标记的代码，方便我测试一下，你的问题应该是数据库没有返回数据的问题，祝学习愉快~

你好同学，建议你在下图标记的地方打印一下员工对象信息，看是否会有数据呢？祝学习愉快~

老师的源码中102行代码是下图标记的内容，建议你粘贴一下你102行的代码，让我看以下是哪处的代码出现了问题，方便具有针对性的为你解答，祝学习愉快~

你好同学，你可以看一下下图报错提示，异常信息是数组下标越界，出现问题的代码在claimVoucherBizImpl类中的第102行代码中。建议同学检查一下该类中的102行处是否出现了数组下标越界的情况，可以打印一下数据看看，祝学习愉快~