mybatis新增save结束后自动返回主键id详解

@Override
    public ChartPagePanel save(ChartPagePanel entity) {
        UserDetails user = SecurityContextHolder.getUserDetails();
        entity.setCreateUser(user.getUsername());
        entity.setLastModifyUser(user.getUsername());
        //entity中的id为null
        chartPagePanelMapper.save(entity);
        //经过save操作后自动返回带id的entity
        // savePanelManage(entity); 其中的entity带有id
        savePanelManage(entity);
        return entity;
    }

    @Transactional
    public void savePanelManage(ChartPagePanel entity){
        if(entity.getChartPageManges()!=null && entity.getChartPageManges().size()>0) {
            Map<String, Object> map = new HashMap<>();
            for (int i = 0; i < entity.getChartPageManges().size(); i++) {
                int manageId = entity.getChartPageManges().get(i).getId();
                map.put("manageId", manageId);
                map.put("panelId", entity.getId());
                chartPagePanelManageMapper.save(map);
            }
        }
    }

useGeneratedKeys=“true” keyProperty=“id”

<insert id="save" parameterType="com.centrin.generator.entity.ChartPagePanel" useGeneratedKeys="true" keyProperty="id">
 insert into chart_page_panel
 (
        `parent_id`,
        `position`,
        `name`,
        `create_time`,
        `create_user`,
        `last_modify_time`,
        `last_modify_user`
        )
 values (
  #{parentId},
  #{position},
  #{name},
  NOW(),
  #{createUser},
  NOW(),
  #{lastModifyUser}
  )
  </insert>

useGeneratedKeys=“true” keyProperty=“id” keyColumn=“id”

<insert id="saveBill" parameterType="com.jd.fp.mrp.domain.model.biz.AdjustBillInfo"
        useGeneratedKeys="true" keyProperty="id" keyColumn="id">
        INSERT INTO adjust_bill_info(external_bill_id, warehouse_code, warehouse_name)
        VALUES(#{externalBillId}, #{warehouseCode}, #{warehouseName});
</insert>

Long id = aTranscationMapper.saveBill(adjustBillInfo);
System.out.println("===========保存受影响的行数："+id+"  保存的id值为："+adjustBillInfo.getId());