crud-development

CRUD 开发指南

通用模板。如果项目有专属技能（如 leniu-crud ），优先使用。

核心规范

三层架构

层职责命名示例

Controller 接收请求、参数校验、路由分发 OrderController

Service 业务逻辑、事务管理 OrderService / OrderServiceImpl

Mapper 数据访问（ORM 映射） OrderMapper

标准包结构

[你的包名]/ ├── controller/ # 控制器 ├── service/ │ └── impl/ # 服务实现 ├── mapper/ # 数据访问层 ├── entity/ # 实体类 ├── dto/ # 请求参数对象 ├── vo/ # 响应视图对象 ├── enums/ # 枚举常量 └── config/ # 模块配置

代码示例

Entity（实体类）

package [你的包名].entity;

import com.baomidou.mybatisplus.annotation.*; import lombok.Data; import java.time.LocalDateTime;

@Data @TableName("t_order") public class Order {

@TableId(type = IdType.ASSIGN_ID)
private Long id;

private String orderNo;

private Integer status;

private Long amount;

@TableField(fill = FieldFill.INSERT)
private String createBy;

@TableField(fill = FieldFill.INSERT)
private LocalDateTime createTime;

@TableField(fill = FieldFill.INSERT_UPDATE)
private String updateBy;

@TableField(fill = FieldFill.INSERT_UPDATE)
private LocalDateTime updateTime;

@TableLogic(value = "0", delval = "1")
private Integer deleted;

}

DTO（请求参数）

package [你的包名].dto;

import jakarta.validation.constraints.*; import lombok.Data;

@Data public class OrderCreateDTO {

@NotBlank(message = "订单号不能为空")
private String orderNo;

@NotNull(message = "金额不能为空")
@Min(value = 1, message = "金额必须大于0")
private Long amount;

}

package [你的包名].dto;

import lombok.Data;

@Data public class OrderQueryDTO {

private String orderNo;

private Integer status;

private Integer pageNum = 1;

private Integer pageSize = 10;

}

VO（响应对象）

package [你的包名].vo;

import lombok.Data; import java.time.LocalDateTime;

@Data public class OrderVO {

private Long id;

private String orderNo;

private Integer status;

private Long amount;

private LocalDateTime createTime;

}

Mapper

package [你的包名].mapper;

import com.baomidou.mybatisplus.core.mapper.BaseMapper; import [你的包名].entity.Order; import org.apache.ibatis.annotations.Mapper;

@Mapper public interface OrderMapper extends BaseMapper<Order> { }

Service

package [你的包名].service;

import com.baomidou.mybatisplus.extension.service.IService; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import [你的包名].entity.Order; import [你的包名].dto.OrderCreateDTO; import [你的包名].dto.OrderQueryDTO; import [你的包名].vo.OrderVO;

public interface IOrderService extends IService<Order> {

Long createOrder(OrderCreateDTO dto);

void updateOrder(Long id, OrderCreateDTO dto);

OrderVO getOrderDetail(Long id);

Page&#x3C;OrderVO> pageQuery(OrderQueryDTO query);

}

package [你的包名].service.impl;

import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper; import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl; import [你的包名].dto.OrderCreateDTO; import [你的包名].dto.OrderQueryDTO; import [你的包名].entity.Order; import [你的包名].mapper.OrderMapper; import [你的包名].service.IOrderService; import [你的包名].vo.OrderVO; import lombok.RequiredArgsConstructor; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; import org.springframework.util.StringUtils;

@Service @RequiredArgsConstructor public class OrderServiceImpl extends ServiceImpl<OrderMapper, Order> implements IOrderService {

@Override
@Transactional(rollbackFor = Exception.class)
public Long createOrder(OrderCreateDTO dto) {
    Order order = new Order();
    // 使用 [你的对象转换工具] 或手动赋值
    order.setOrderNo(dto.getOrderNo());
    order.setAmount(dto.getAmount());
    order.setStatus(0);
    this.save(order);
    return order.getId();
}

@Override
@Transactional(rollbackFor = Exception.class)
public void updateOrder(Long id, OrderCreateDTO dto) {
    Order order = this.getById(id);
    if (order == null) {
        throw new [你的业务异常类]("订单不存在");
    }
    order.setOrderNo(dto.getOrderNo());
    order.setAmount(dto.getAmount());
    this.updateById(order);
}

@Override
public OrderVO getOrderDetail(Long id) {
    Order order = this.getById(id);
    if (order == null) {
        throw new [你的业务异常类]("订单不存在");
    }
    OrderVO vo = new OrderVO();
    // 使用 [你的对象转换工具] 或手动赋值
    vo.setId(order.getId());
    vo.setOrderNo(order.getOrderNo());
    vo.setStatus(order.getStatus());
    vo.setAmount(order.getAmount());
    vo.setCreateTime(order.getCreateTime());
    return vo;
}

@Override
public Page&#x3C;OrderVO> pageQuery(OrderQueryDTO query) {
    Page&#x3C;Order> page = new Page&#x3C;>(query.getPageNum(), query.getPageSize());
    LambdaQueryWrapper&#x3C;Order> wrapper = new LambdaQueryWrapper&#x3C;Order>()
            .like(StringUtils.hasText(query.getOrderNo()), Order::getOrderNo, query.getOrderNo())
            .eq(query.getStatus() != null, Order::getStatus, query.getStatus())
            .orderByDesc(Order::getCreateTime);
    Page&#x3C;Order> result = this.page(page, wrapper);

    // 转换为 VO
    Page&#x3C;OrderVO> voPage = new Page&#x3C;>(result.getCurrent(), result.getSize(), result.getTotal());
    voPage.setRecords(result.getRecords().stream().map(order -> {
        OrderVO vo = new OrderVO();
        vo.setId(order.getId());
        vo.setOrderNo(order.getOrderNo());
        vo.setStatus(order.getStatus());
        vo.setAmount(order.getAmount());
        vo.setCreateTime(order.getCreateTime());
        return vo;
    }).toList());
    return voPage;
}

}

Controller

package [你的包名].controller;

import com.baomidou.mybatisplus.extension.plugins.pagination.Page; import [你的包名].dto.OrderCreateDTO; import [你的包名].dto.OrderQueryDTO; import [你的包名].service.IOrderService; import [你的包名].vo.OrderVO; import jakarta.validation.Valid; import lombok.RequiredArgsConstructor; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*;

@RestController @RequestMapping("/api/v1/orders") @RequiredArgsConstructor public class OrderController {

private final IOrderService orderService;

@PostMapping
public ResponseEntity&#x3C;Long> create(@Valid @RequestBody OrderCreateDTO dto) {
    return ResponseEntity.ok(orderService.createOrder(dto));
}

@PutMapping("/{id}")
public ResponseEntity&#x3C;Void> update(@PathVariable Long id,
                                   @Valid @RequestBody OrderCreateDTO dto) {
    orderService.updateOrder(id, dto);
    return ResponseEntity.ok().build();
}

@GetMapping("/{id}")
public ResponseEntity&#x3C;OrderVO> detail(@PathVariable Long id) {
    return ResponseEntity.ok(orderService.getOrderDetail(id));
}

@GetMapping
public ResponseEntity&#x3C;Page&#x3C;OrderVO>> page(OrderQueryDTO query) {
    return ResponseEntity.ok(orderService.pageQuery(query));
}

@DeleteMapping("/{id}")
public ResponseEntity&#x3C;Void> delete(@PathVariable Long id) {
    orderService.removeById(id);
    return ResponseEntity.ok().build();
}

}

常见错误

错误正确做法

Controller 里写业务逻辑业务逻辑放 Service 层

直接返回 Entity 给前端使用 VO 封装响应数据

用 Map 传递业务数据使用 DTO/VO 强类型对象

忘记加 @Transactional

写操作方法加事务注解

逻辑删除字段值搞反确认项目约定（通用：0=正常, 1=删除）

分页参数未设默认值 DTO 中给 pageNum/pageSize 默认值

Service 之间循环依赖提取公共 Service 或使用事件机制解耦

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