工作笔记【六】

任务1.对数据表进行CRUD操作

第一个任务首先是最基本的CRUD操作，很简单，直接放代码

package com.example.demo.demos.web.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;@Data
@NoArgsConstructor
@AllArgsConstructor
public class Column {private int id; //充电桩idprivate String number; //编号private String pileId; //对应充电站idprivate int voltageMin; //充电桩最小电压private int voltageMax; //充电桩最大电压private int voltage; //充电速率（1-快充 2-慢充）private int state; //充电桩状态（1-正常 2-故障）
}

package com.example.demo.demos.web.mapper;import com.example.demo.demos.web.pojo.Column;
import org.apache.ibatis.annotations.*;import java.util.List;@Mapper
public interface ColumnMapper {@Select("select * from `column`")List<Column> list();@Insert("insert into `column`(id,number,pile_id) values(#{id},#{number},#{pileId})")void insert(Column column);@Delete("delete from `column` where id = #{id}")void deleteById(Integer id);@Select("select count(*) from `column` where id = #{id}")String checkId(Integer id);@Update("update `column` set number = #{number} where id = #{id}")void update(Column column);@Select("select count(*) from `column` where number = #{number}")String checkNumberDuplicate(String number);
}

package com.example.demo.demos.web.controller;import com.example.demo.demos.web.pojo.Column;
import com.example.demo.demos.web.pojo.Result;
import com.example.demo.demos.web.service.ColumnService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;import java.util.List;
@RestController
@Slf4j
@RequestMapping("/column")
public class ColumnController {@Autowiredprivate ColumnService columnService;@GetMapping("/select")public Result getAllColumn() {log.info("查询全部充电桩信息");List<Column> columnList = columnService.list();return Result.success(columnList);}@PostMapping("/insert")public Result insertColumn(Column column) {log.info("新增充电桩：{}", column);columnService.add(column);return Result.success(column);}@DeleteMapping("/delete/{id}")public Result deleteColumn(@PathVariable Integer id) {log.info("根据id删除充电桩：{}",id);String ss = columnService.delete(id);return Result.success(ss);}@PutMapping("/update")public Result updateColumn(Column column) {log.info("修改充电桩信息：{}", column);String ss =  columnService.update(column);return Result.success(ss);}}

package com.example.demo.demos.web.service;import com.example.demo.demos.web.pojo.Column;import java.util.List;public interface ColumnService {List<Column> list();void add(Column column);String delete(Integer id);String update(Column column);
}

package com.example.demo.demos.web.service.impl;import com.example.demo.demos.web.mapper.ColumnMapper;
import com.example.demo.demos.web.pojo.Column;
import com.example.demo.demos.web.service.ColumnService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;import java.util.List;@Service
public class ColumnServiceImpl implements ColumnService {@Autowiredprivate ColumnMapper columnMapper;@Overridepublic List<Column> list(){List<Column> ss= columnMapper.list();return ss;}@Overridepublic void add(Column column){columnMapper.insert(column);}@Overridepublic String delete(Integer id){List<Column> ss= columnMapper.list();for (Column column:ss){if (column.getId() == id){columnMapper.deleteById(id);return "删除成功";}}return "删除失败，编号不存在";}@Overridepublic String update(Column column) {checkNumberDuplicate(column.getNumber());if (checkNumberDuplicate(column.getNumber())){columnMapper.update(column);return "修改成功";}return "修改失败，编号重复";}public boolean checkNumberDuplicate(String number){List<Column> ss= columnMapper.list();for (Column column : ss){if (column.getNumber().equals(number)){return false;}}return true;}
}

任务2：对删除和修改操作添加条件

第一个是根据id删除数据，要判断是否存在该id，就在mapper中添加一条：

 @Delete("delete from `column` where id = #{id}")void deleteById(Integer id);@Select("select count(*) from `column` where id = #{id}")String checkId(Integer id);

并且在ColumnServiceImpl添加一个判断语句：

@Overridepublic String delete(Integer id){List<Column> ss= columnMapper.list();for (Column column:ss){if (column.getId() == id){columnMapper.deleteById(id);return "删除成功";}}return "删除失败，编号不存在";}

这样就完成了对id的检查。

第二个是在修改数据信息时，number数据内容不能重复，同样在mapper中添加一条语句：

    @Update("update `column` set number = #{number} where id = #{id}")void update(Column column);@Select("select count(*) from `column` where number = #{number}")String checkNumberDuplicate(String number);

并且在ColumnServiceImpl添加一个判断语句和一个判断方法：

@Overridepublic String update(Column column) {checkNumberDuplicate(column.getNumber());if (checkNumberDuplicate(column.getNumber())){columnMapper.update(column);return "修改成功";}return "修改失败，编号重复";}public boolean checkNumberDuplicate(String number){List<Column> ss= columnMapper.list();for (Column column : ss){if (column.getNumber().equals(number)){return false;}}return true;}

这样就完成了条件限制。

任务3：添加拦截器拦截查询请求

新建一个filter包，用于存放拦截器文件。

@Component
public class SelectInterceptor implements HandlerInterceptor {private static final Logger logger = Logger.getLogger(String.valueOf(SelectInterceptor.class));@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {String path = request.getRequestURI();logger.info(path);if (path.contains("/select")) {logger.info("请求禁用，系统维护中");response.setContentType("text/plain;charset=UTF-8");response.getWriter().write("系统维护中");return false;} else {return true;}}
}

新建类SelectInterceptor，去进行拦截操作，return false表示禁用，禁用拦截后，在操作台打印出“请求禁用，系统维护中”，使用response返回提示信息。

另外还需要新建一个WebConfig注入拦截器

@Configuration
public class WebConfig implements WebMvcConfigurer {@Autowiredprivate SelectInterceptor selectInterceptor;@Overridepublic void addInterceptors(InterceptorRegistry registry) {registry.addInterceptor(selectInterceptor);}
}

这样就完成了任务3。

任务4：写一个上传文件的接口

这个其实很简单，基本和网上的示例差不多，稍加修改就好

这边的需求是将文件存至指定位置，并且使用当前时间为文件命名

package com.example.demo.demos.web.controller;import lombok.extern.flogger.Flogger;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
@Slf4j
@RestController
public class FileUploadController {@PostMapping("/upload")public ResponseEntity<String> uploadFile(MultipartFile file) {if (file.isEmpty()) {return new ResponseEntity<>(HttpStatus.BAD_REQUEST);}try {SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");String fileName = sdf.format(new Date()) + "_" + file.getOriginalFilename();String filePath = "D:/UploadTest/" + fileName;File dest = new File(filePath);file.transferTo(dest);log.info("文件上传成功，新文件名：" + fileName);return new ResponseEntity<>(HttpStatus.OK);} catch (IOException e) {log.info("文件上传失败");return new ResponseEntity<>(HttpStatus.INTERNAL_SERVER_ERROR);}}
}

另外，附上项目结构图