如何写一个接口

此接口非彼接口。此接口是MVC的设计模式中的Controller层，一般我们会叫Controller层里的方法为接口。他们是负责

接收前端或者其它服务的传来的请求，并对请求进行相应的处理，最终再将处理结果返回给前端或者其它服务。

1.模糊分页查询

• Controller层

@RestController
@RequestMapping("camera")
public class CameraAlarmController {

  @Autowired
  private IWarehouseOutService warehouseOutService; //注入接口

  /**
     * 获取设备相关信息
     * @param equipAttribute
     * @param equipType
     * @param keywords
     * @param pageNum
     * @param pageSize
     * @return
     */
  @GetMapping("getOutboundEquipmentInfo")
  public Result getOutboundEquipmentInfo(@RequestParam(value ="operationType",required = false) @RequestParam(value ="pageNum",required = false, defaultValue = "1") Integer pageNum,@RequestParam(value ="pageSize", required = false, defaultValue = "10") Integer pageSize){
    PageHelper.startPage(pageNum,pageSize);
    PageInfo<OutboundEquipmentInfoVo> pageInfo=new PageInfo<>(warehouseOutService.getOutboundEquipmentInfo(equipAttribute，equipTypeId,warehouseId,operationType,keywords));
    return new SuccessResult(pageInfo);
  }
}

在进行模糊查询操作的时候，往往有时候需要查询的参数很多，这时候也可以考虑使用实体类接收前端传参，更改如下：

    @PostMapping("/getOutboundEquipmentInfo")//这里改成post请求
    public Result getOutboundEquipmentInfo(@RequestBody  EquipInfoVo vo){
       PageHelper.startPage(vo.getPageNum(),vo.getPageSize());
       PageInfo<OutboundEquipmentInfoVo> pageInfo=new PageInfo<>(warehouseOutService.getOutboundEquipmentInfo(vo));
       return new SuccessResult(pageInfo);
    }

接收前端传参实体类代码如下：

@Data
@Accessors(chain = true)
public class EquipInfoVo {
    @JsonProperty(value = "operationType")
    private Integer operationType;
    @JsonProperty(value = "warehouseId")
    private Integer warehouseId;
    @JsonProperty(value = "equipAttribute")
    private String equipAttribute;
    @JsonProperty(value = "equipTypeId")
    private Integer equipTypeId;
    @JsonProperty(value = "keywords")
    private String keywords;
    @JsonProperty(value = "pageNum")
    private Integer pageNum=1;
    @JsonProperty(value = "pageSize")
    private Integer pageSize=10;
}

• service层

  定义service层接口（此接口就是我们Java中用intrerface关键字定义的接口了）

  //这里不用加service注解
  public interface IWarehouseOutService {
    
      List<OutboundEquipmentInfoVo> getOutboundEquipmentInfo(String equipAttribute,
                                                             Integer equipTypeId,
                                                             Integer warehouseId,
                                                             Integer operationType,
                                                             String keywords);
  
  }
  

  定义service接口实现

  @Service
  @Slf4j
  public class WarehouseOutServiceImpl implements IWarehouseOutService {
      
       @Autowired
      private WmEquipInfoMapper wmEquipInfoMapper;
  
   
   @Override
      public List<OutboundEquipmentInfoVo> getOutboundEquipmentInfo(String equipAttribute,
                                                                    Integer equipTypeId,
                                                                    Integer warehouseId,
                                                                    Integer operationType,
                                                                    String keywords) {
          //入库操作
          if (operationType==WmConstant.EQUIPMENT_INFO_INCOME){
              List<OutboundEquipmentInfoVo> outList=wmEquipInfoMapper.getEquipmentInformation(equipAttribute,equipTypeId,keywords);
              List<WmRepertoryInfoDto> allEquip = wmRepertoryInfoMapper.getAllEquip(warehouseId);
              outList.forEach(info->{
                  Optional<WmRepertoryInfoDto> wmRepertoryInfoDto = allEquip.stream().filter(all -> all.getEquipId().equals(info.getId())).findFirst();
                  if (wmRepertoryInfoDto.isPresent()){
                      info.setInventoryQuantity(wmRepertoryInfoDto.get().getNum());
                      info.setDamagesNum(wmRepertoryInfoDto.get().getDamagesNum());
                  }else {
                      info.setInventoryQuantity(0);
                      info.setDamagesNum(0);
                  }
              });
              return outList;
          }else{
              //出库操作
              List<OutboundEquipmentInfoVo> outboundEquipmentInfo = wmEquipInfoMapper.getOutboundEquipmentInfo(equipAttribute, warehouseId, equipTypeId, keywords);
              List<WmRelationEquipDto> relationEquipDtos=wmOutWarehouseMapper.getOutboundApproval(warehouseId);
              outboundEquipmentInfo.forEach(out-> relationEquipDtos.forEach(re->{
                      if (Integer.valueOf(re.getEquipId().toString()).equals(out.getId())){
                          Integer num=out.getInventoryQuantity()-re.getNum();
                          out.setInventoryQuantity(num<0?0:num);
                      }
                  })
              );
              return outboundEquipmentInfo;
          }
      }
  }
  

  • mapper层

  //这上面不加@Mapper注解就要，在启动类上加这个注解@MapperScan("com.zcloud.dao.mapper")
  public interface WmEquipInfoMapper {
  
    List<OutboundEquipmentInfoVo> getOutboundEquipmentInfo(@Param("equipAttribute") String equipAttribute,
                                                             @Param("warehouseId") Integer warehouseId,
                                                             @Param("equipTypeId") Integer equipTypeId,
                                                             @Param("keywords") String keywords);
  }
  

  ​

  <select id="getOutboundEquipmentInfo" resultType="com.zcloud.domain.warehousemanage.vo.OutboundEquipmentInfoVo">
      SELECT
          t2.num inventoryQuantity,
          t2.damages_num,
          ( SELECT `name` FROM t_dic_item WHERE type_code = "equip_attribute" AND CODE = t1.equip_attribute ) `equipAttributeName`,
          ( SELECT `name` FROM t_dic_item WHERE type_code = "equip_unit" AND CODE = t1.equip_unit ) equipUnitName,
          t1.equip_name,
          t1.equip_brand,
          t1.id,
          t1.equip_model,
          t3.`name` equipTypeName
      FROM
          t_common_wm_equip_info t1
          LEFT JOIN t_common_wm_repertory_info t2 ON t1.id = t2.equip_id
          LEFT JOIN t_common_wm_equip_type t3 ON t1.equip_type_id = t3.id
      WHERE
          t1.removed = 0
          AND t2.removed =0
          AND t3.removed=0
          AND t2.warehouse_id=#{warehouseId}
      <if test="equipAttribute!=null and equipAttribute!=''">
          AND t1.equip_attribute=#{equipAttribute}
      </if>
      //注意Interge类型的条件判断是否为空的时候一定不要加非空字符串判断，因为当你传的值为0的时候，mybatis会把它判断为空字符串
      <if test="equipTypeId!=null">  
          AND t1.equip_type_id=#{equipTypeId}
      </if>
          <if test="keywords!=null and keywords!=''">
              AND (t1.equip_name like concat('%',#{keywords})
              OR t1.equip_model like concat('%',#{keywords})
              OR t1.equip_brand like concat('%',#{keywords}))
          </if>
  </select>
  

​

2.批量删除

• controller层

      @DeleteMapping(value = "/delete", name = "仓库管理，删除仓库信息")
      public Result deleteWareHouseInfo(@RequestParam(value = "ids") String ids,HttpServletRequest request
                                   ) {
           Integer userId = (Integer) RequestUtils.getCurrentUser(request).get("userId");
          return new SuccessResult(wareHouseInfoService.deleteWareHouseInfo(ids,userId));
      }
  

  1,2,3

• service层

  @Transactional //单表删除不加这个注解可以，多表关联删除一定要加
  public Object deleteWareHouseInfo(Integer ids, Integer userId) {
            List<Integer> idList = Arrays.stream(ids.split(","))
                  .map(s -> Integer.parseInt(s.trim())).collect(Collectors.toList());
          return warehouseInfoMapper.deleteByIds(idList,userId);
      }
  

• mapper层

   Integer deleteByIds(@Param("idList")  List<Integer> idList,
                         @Param("userId") Integer userId);
  

      <update id="deleteByIds" parameterType="java.lang.Integer">
         <foreach collection="idList" item="item" separator=";">
          update t_warehouse_info
          set removed = 1,
          rm_uid = #{userId},
          rm_time = NOW(),
          up_time = now()
          where id =#{item.id}
         </foreach>
      </update>
  

3.新增

• controller层

    @PostMapping(value = "/add", name = "仓库管理，新增采购")
      public Result addPurchaseInfo(@RequestBody WmPurchaseInfoAddVo dto, HttpServletRequest request) {
          Integer userId = (Integer) RequestUtils.getCurrentUser(request).get("userId");
          return new SuccessResult(wmPurchaseInfoService.addPurchaseInfo(dto,userId));
      }
  

• service层

      @Override
      @Transactional
      public Integer addPurchaseInfo(WmPurchaseInfoAddVo dto, Integer userId) { 
          Integer result;
          String orderCode = wmUtils.generateWmCode(WmConstant.PURCHASE_CODE_PREFIX, 1);
          dto.setOrderCode(orderCode).setCrUid(userId).setUpUid(userId);
          //插入采购基本信息，返回id
          //需要注意的是，如果待插入数据的表未设置主键自增，则在这里需要设置主键的值
          //而这里是设置了主键自增，所以就需要在mapper层配置sql语句的时候，设置返回自增的主键值
          purchaseInfoMapper.insertSelective(dto);
          List<WmRelationEquipDto> wmRelationEquipDtos = dto.getRelationEquip();
          //设置关联设备的，关联id，以及关联类型
          wmRelationEquipDtos.forEach(e -> {
              e.setRelationId(dto.getId()).setType(WmConstant.PURCHASE_RELATION)
                      .setStockPendingNum(e.getNum());
          });
          //插入关联设备信息
          result = relationEquipMapper.insertBatch(wmRelationEquipDtos);
          return result >= 1 ? 1 : 0;
      }
  
  

• mapper层

  purchaseInfoMapper.insertSelective(dto);

    <insert id="insertSelective" useGeneratedKeys="true" keyProperty="id" keyColumn="id"
            parameterType="vip.dtcloud.domain.warehousemanage.vo.WmPurchaseInfoAddVo">
      insert into t_common_wm_purchase_info
      <trim prefix="(" suffix=")" suffixOverrides=",">
        <if test="addVo.orderCode != null">
          order_code,
        </if>
        <if test="addVo.orderName != null">
          order_name,
        </if>
        <if test="addVo.purchaseMethod != null">
          purchase_method,
        </if>
        <if test="addVo.purchaseManager != null">
          purchase_manager,
        </if>
        <if test="addVo.orderDate != null">
          order_date,
        </if>
        <if test="addVo.contractId != null">
          contract_id,
        </if>
        <if test="addVo.biddingDocumentIds != null">
          bidding_document_ids,
        </if>
        <if test="addVo.purchaseContractIds != null">
          purchase_contract_ids,
        </if>
        <if test="addVo.meetingSummaryIds != null">
          meeting_summary_ids,
        </if>
        <if test="addVo.otherFilesIds != null">
          other_files_ids,
        </if>
        <if test="addVo.remark != null">
          remark,
        </if>
        up_time,
        cr_time,
        <if test="addVo.upUid != null">
          up_uid,
        </if>
        <if test="addVo.crUid != null">
          cr_uid,
        </if>
      </trim>
      <trim prefix="values (" suffix=")" suffixOverrides=",">
        <if test="addVo.orderCode != null">
          #{addVo.orderCode,jdbcType=VARCHAR},
        </if>
        <if test="addVo.orderName != null">
          #{addVo.orderName,jdbcType=VARCHAR},
        </if>
        <if test="addVo.purchaseMethod != null">
          #{addVo.purchaseMethod,jdbcType=VARCHAR},
        </if>
        <if test="addVo.purchaseManager != null">
          #{addVo.purchaseManager,jdbcType=VARCHAR},
        </if>
        <if test="addVo.orderDate != null">
          #{addVo.orderDate,jdbcType=TIMESTAMP},
        </if>
        <if test="addVo.contractId != null">
          #{addVo.contractId,jdbcType=INTEGER},
        </if>
        <if test="addVo.biddingDocumentIds != null">
          #{addVo.biddingDocumentIds,jdbcType=VARCHAR},
        </if>
        <if test="addVo.purchaseContractIds != null">
          #{addVo.purchaseContractIds,jdbcType=VARCHAR},
        </if>
        <if test="addVo.meetingSummaryIds != null">
          #{addVo.meetingSummaryIds,jdbcType=VARCHAR},
        </if>
        <if test="addVo.otherFilesIds != null">
          #{addVo.otherFilesIds,jdbcType=VARCHAR},
        </if>
        <if test="addVo.remark != null">
          #{addVo.remark,jdbcType=VARCHAR},
        </if>
        now(),
        now(),
        <if test="addVo.upUid != null">
          #{addVo.upUid,jdbcType=INTEGER},
        </if>
        <if test="addVo.crUid != null">
          #{addVo.crUid,jdbcType=INTEGER},
        </if>
      </trim>
    </insert>
  

relationEquipMapper.insertBatch(wmRelationEquipDtos);

<insert id="insertBatch">
        insert into t_common_wm_relation_equip (relation_id, type,
        equip_id, equip_serial, equip_code,
        num, stock_pending_num, up_time
        )
        values
        <foreach collection="dtoList" item="item" separator=",">
            ( #{item.relationId,jdbcType=INTEGER}, #{item.type,jdbcType=INTEGER},
            #{item.equipId,jdbcType=BIGINT}, #{item.equipSerial,jdbcType=VARCHAR}, #{item.equipCode,jdbcType=VARCHAR},
            #{item.num,jdbcType=INTEGER}, #{item.stockPendingNum,jdbcType=INTEGER}, now()
            )
        </foreach>
    </insert>

注意 ： 做批量插入的时候，插入的数量不能太多，否则会因为sql语句过长而出现无法执行的问题。一般超过5000条的话就可以使用分页去插入了。比如可以改成

如下这样的插入：

            
            List<List<EquipRealVariableDto>> lists = splitList(wmRelationEquipDtos, 5000);
            lists.forEach(e -> {
                 result += relationEquipMapper.insertBatch(e);
            });

splitList方法代码如下：

    private static <T> List<List<T>> splitList(List<T> list, int splitCount) {
        int length = list.size();
        long totalLength = (long)length + (long)splitCount - 1L;
        long num = totalLength / (long)splitCount;
        List<List<T>> newList = new ArrayList();

        for(int i = 0; (long)i < num; ++i) {
            int fromIndex = i * splitCount;
            int toIndex = (i + 1) * splitCount < length ? (i + 1) * splitCount : length;
            newList.add(list.subList(fromIndex, toIndex));
        }

        return newList;
    }

4.编辑

• controller层

    @PutMapping(value = "/edit", name = "仓库管理，修改仓库信息")
    public Result editWareHouseInfo(@RequestBody WmWarehouseInfoDto dto,HttpServletRequest request) {
        Integer userId = (Integer) RequestUtils.getCurrentUser(request).get("userId");
        return new SuccessResult(wareHouseInfoService.editWareHouseInfo(dto,userId));
    }

• Service层

    @Override
      public Integer editWareHouseInfo(WmWarehouseInfoDto dto, Integer userId) {
          dto.setUpUid(userId);
          return warehouseInfoMapper.updateByPrimaryKeySelective(dto);
      }
  

• mapper层

   <update id="updateByPrimaryKeySelective" parameterType="vip.dtcloud.domain.warehousemanage.dto.WmWarehouseInfoDto">
          update t_common_wm_warehouse_info
          <set>
              <if test="warehouseName != null">
                  warehouse_name = #{warehouseName,jdbcType=VARCHAR},
              </if>
              <if test="warehouseLocation != null">
                  warehouse_location = #{warehouseLocation,jdbcType=VARCHAR},
              </if>
              <if test="warehouseManager != null">
                  warehouse_manager = #{warehouseManager,jdbcType=VARCHAR},
              </if>
              <if test="phone != null">
                  phone = #{phone,jdbcType=VARCHAR},
              </if>
              <if test="departmentId != null">
                  department_id = #{departmentId,jdbcType=VARCHAR},
              </if>
              <if test="warehouseStatus != null">
                  warehouse_status = #{warehouseStatus,jdbcType=INTEGER},
              </if>
              up_time = now(),
              <if test="upUid != null">
                  up_uid = #{upUid,jdbcType=INTEGER},
              </if>
          </set>
          where id = #{id,jdbcType=INTEGER}
      </update>
  

终极大法 ： 看别人是怎么写的，Ctrl c ctrl v ，然后改一改