1.controller

public class DemandController {

    @Autowired
    private DemandService demandService;

    @PostMapping("/add")
    public R add(@RequestBody Demand demand, HttpServletRequest request){
//        Principal userPrincipal = request.getUserPrincipal();
//        String userName = userPrincipal.getName();
        Demand result = demandService.add(demand, "admin");
        if(null != result){
            return R.ok(result, "提交成功!");
        }else{
            return R.fail("提交失败!");
        }
    }

    @GetMapping("/{id}}")
    public R selectById(@PathVariable Long id){
        return R.ok(demandService.selectById(id), "查询成功!");
    }

    @PostMapping
    public R selectDemands(@RequestBody Demand demand){
        return R.ok(demandService.selectDemands(demand), "查询成功!");
    }
}

2. service

@Service
public class DemandServiceImpl implements DemandService {

    @Autowired
    private DemandMapper demandMapper;
    @Autowired
    private SysUserService userService;

    @Override
    @Transactional
    public Demand add(Demand demand, String userName) {
        LoginUser loginUser = userService.selectUserByUserName(userName);
        demand.setUserId(loginUser.getSysUser().getUserId());
        demand.setCreateBy(userName);
        int rows = demandMapper.add(demand);
        return rows > 0 ? demand : null;
    }

    @Override
    public Demand selectById(Long id) {
        return demandMapper.selectById(id);
    }

    @Override
    public List<Demand> selectDemands(Demand demand) {
        return demandMapper.selectDemands(demand);
    }

    @Override
    @Transactional
    public int delById(Long id) {
        return 0;
    }

    @Override
    @Transactional
    public int delByIds(List<Long> ids) {
        return 0;
    }

    @Override
    @Transactional
    public Demand updateDemand(Demand demand) {
        return null;
    }
}

3. mapper

public interface DemandMapper {

    int add(Demand demand);

    Demand selectById(Long id);

    List<Demand> selectDemands(Demand demand);

//    int delById(Long id);
//
//    int delByIds(List<Long> ids);
//
//    Demand updateDemand(Demand demand);

}

4. xml

<?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="com.guanwei.dao.DemandMapper">

    <resultMap id="DemandResult" type="com.guanwei.model.Demand">
        <id     property="id"       column="id"      />
        <result property="userId"       column="user_id"      />
        <result property="headName"     column="head_name"    />
        <result property="headGender"     column="head_gender"    />
        <result property="headPhone"     column="head_phone"    />
        <result property="summarize"        column="summarize"        />
        <result property="filePath"  column="file_path"  />
        <result property="type"          column="type"          />
        <result property="solve"          column="solve"          />
        <result property="createBy"     column="create_by"    />
        <result property="createTime"   column="create_time"  />
        <result property="updateBy"     column="update_by"    />
        <result property="updateTime"   column="update_time"  />
        <result property="remark"       column="remark"       />
    </resultMap>

    <sql id="selectDemand">
        select d.id, d.user_id, d.head_name, d.head_phone, d.summarize, d.file_path, d.type, d.solve,
        d.create_by, d.create_time, d.update_by, d.update_time, d.remark
        from demand d
    </sql>

    <insert id="add" parameterType="com.guanwei.model.Demand" useGeneratedKeys="true" keyProperty="id">
        insert into demand (
            <if test="id !=null and id !=0">id,</if>
            <if test="userId !=null and userId !=0">user_id,</if>
            <if test="headName !=null and headName !=''">head_name,</if>
            <if test="headPhone !=null and headPhone !=''">head_phone,</if>
            <if test="summarize !=null and summarize !=''">summarize,</if>
            <if test="filePath !=null and filePath !=''">file_path,</if>
            <if test="type !=null and type !=''">type,</if>
            <if test="solve !=null and solve !=''">solve,</if>
            <if test="createBy != null and createBy != ''">create_by,</if>
            <if test="remark != null and remark != ''">remark,</if>
            create_time
        ) values (
            <if test="id !=null and id !=0">#{id},</if>
            <if test="userId !=null and userId !=0">#{userId},</if>
            <if test="headName !=null and headName !=''">#{headName},</if>
            <if test="headPhone !=null and headPhone !=''">#{headPhone},</if>
            <if test="summarize !=null and summarize !=''">#{summarize},</if>
            <if test="filePath !=null and filePath !=''">#{filePath},</if>
            <if test="type !=null and type !=''">#{type},</if>
            <if test="solve !=null and solve !=''">#{solve},</if>
            <if test="createBy != null and createBy != ''">#{createBy},</if>
            <if test="remark != null and remark != ''">#{remark},</if>
            sysdate()
        )
    </insert>

    <select id="selectById" parameterType="Long" resultMap="DemandResult">
        <include refid="selectDemand"/>
        where id=#{id}
    </select>

    <select id="selectDemands" parameterType="com.guanwei.model.Demand" resultMap="DemandResult">
        <include refid="selectDemand"/>
        where 1=1
        <if test="headName != null and headName != ''">
            AND d.head_name like concat('%', #{headName}, '%')
        </if>
        <if test="headPhone != null and headPhone != ''">
            AND d.head_phone like concat('%', #{headPhone}, '%')
        </if>
        <if test="params.beginTime != null and params.beginTime != ''"><!-- 开始时间检索 -->
            AND date_format(u.create_time,'%y%m%d') &gt;= date_format(#{params.beginTime},'%y%m%d')
        </if>
        <if test="params.endTime != null and params.endTime != ''"><!-- 结束时间检索 -->
            AND date_format(u.create_time,'%y%m%d') &lt;= date_format(#{params.endTime},'%y%m%d')
        </if>
        <if test="type != null and type != ''">
            AND type = #{type}
        </if>
        <if test="solve != null and solve != ''">
            AND solve = #{solve}
        </if>
        <if test="createBy != null and createBy != ''">
            AND createBy = #{createBy}
        </if>
        <!-- 数据范围过滤 -->
        ${params.dataScope}
    </select>

</mapper>

4.分析

4.1 返回主键?

int 没办法直接是主键,主键只能赋值给对象的id;
想要获取,getId()吧!!!