数据库表导出到excel

数据库表导出到excel:前置知识1 ALL_TAB_COLS
数据库表导出到excel:前置知识2 Quartz基本使用
数据库表导出到excel:前置知识3 项目封装的Quartz实现动态定时任务
数据库表导出到excel:前置知识4 业务和效果

	发起清单下载

control层InventoryDownloadLogController

/*
* 
*/
package com.njry.sjzl.busi.rest;import com.njry.annotation.Log;
import com.njry.sjzl.busi.domain.InventoryDownloadLog;
import com.njry.sjzl.busi.service.InventoryDownloadLogService;
import com.njry.sjzl.busi.domain.vo.InventoryDownloadLogQueryCriteria;
import lombok.RequiredArgsConstructor;
import java.util.List;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;
import io.swagger.annotations.*;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.njry.utils.PageResult;/**
* @author wj
* @date 2024-06-20
**/
@RestController
@RequiredArgsConstructor
@Api(tags = "清单任务下载表管理")
@RequestMapping("/api/inventoryDownloadLog")
public class InventoryDownloadLogController {private final InventoryDownloadLogService inventoryDownloadLogService;@Log("导出数据")@ApiOperation("导出数据")@GetMapping(value = "/download")@PreAuthorize("@el.check('inventoryDownloadLog:list')")public void exportInventoryDownloadLog(HttpServletResponse response, InventoryDownloadLogQueryCriteria criteria) throws IOException {inventoryDownloadLogService.download(inventoryDownloadLogService.queryAll(criteria), response);}@Log("下载文件")@ApiOperation("下载文件")@GetMapping(value = "/downloadFile")@PreAuthorize("@el.check('inventoryDownloadLog:list')")public void exportInventoryDownloadLogFile(HttpServletResponse response, InventoryDownloadLogQueryCriteria criteria) throws IOException {String attachmentId = criteria.getAttachmentId();inventoryDownloadLogService.downloadFile(attachmentId, response);}@GetMapping@Log("查询清单任务下载日志表")@ApiOperation("查询清单任务下载日志表")@PreAuthorize("@el.check('inventoryDownloadLog:list')")public ResponseEntity<PageResult<InventoryDownloadLog>> queryInventoryDownloadLog(InventoryDownloadLogQueryCriteria criteria, Page<Object> page){return new ResponseEntity<>(inventoryDownloadLogService.queryAll(criteria,page),HttpStatus.OK);}@PostMapping@Log("新增清单任务下载日志表--发起-----------调度任务异步把table数据变成文件")@ApiOperation("新增清单任务下载日志表--发起-----------调度任务异步把table数据变成文件")@PreAuthorize("@el.check('inventoryDownloadLog:add')")public ResponseEntity<Object> createInventoryDownloadLog(@Validated @RequestBody InventoryDownloadLog resources){inventoryDownloadLogService.create(resources);return new ResponseEntity<>(HttpStatus.CREATED);}//    @PutMapping
//    @Log("修改清单任务下载日志表")
//    @ApiOperation("修改清单任务下载日志表")
//    @PreAuthorize("@el.check('inventoryDownloadLog:edit')")
//    public ResponseEntity<Object> updateInventoryDownloadLog(@Validated @RequestBody InventoryDownloadLog resources){
//        inventoryDownloadLogService.update(resources);
//        return new ResponseEntity<>(HttpStatus.NO_CONTENT);
//    }@DeleteMapping@Log("删除清单任务下载日志表")@ApiOperation("删除清单任务下载日志表")@PreAuthorize("@el.check('inventoryDownloadLog:del')")public ResponseEntity<Object> deleteInventoryDownloadLog(@RequestBody List<Long> ids) {inventoryDownloadLogService.deleteAll(ids);return new ResponseEntity<>(HttpStatus.OK);}
}

service层

/*
*
*/
package com.njry.sjzl.busi.service;import com.njry.sjzl.busi.domain.InventoryDownloadLog;
import com.njry.sjzl.busi.domain.vo.InventoryDownloadLogQueryCriteria;
import java.util.Map;
import java.util.List;
import java.io.IOException;
import javax.servlet.http.HttpServletResponse;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.IService;
import com.njry.utils.PageResult;/**
* @description 服务接口
* @author wj
* @date 2024-06-20
**/
public interface InventoryDownloadLogService extends IService<InventoryDownloadLog> {/*** 查询数据分页* @param criteria 条件* @param page 分页参数* @return PageResult*/PageResult<InventoryDownloadLog> queryAll(InventoryDownloadLogQueryCriteria criteria, Page<Object> page);/*** 查询所有数据不分页* @param criteria 条件参数* @return List<InventoryDownloadLogDto>*/List<InventoryDownloadLog> queryAll(InventoryDownloadLogQueryCriteria criteria);/*** 创建* @param resources /*/void create(InventoryDownloadLog resources);//    /**
//    * 编辑
//    * @param resources /
//    */
//    void update(InventoryDownloadLog resources);/*** 多选删除* @param ids /*/void deleteAll(List<Long> ids);/*** 导出数据* @param all 待导出的数据* @param response /* @throws IOException /*/void download(List<InventoryDownloadLog> all, HttpServletResponse response) throws IOException;/*** 导出文件* @param attachmentId 文件名* @param response /* @throws IOException /*/void downloadFile(String attachmentId, HttpServletResponse response) throws IOException;}

实现层impl(主要看create方法)

/*
*
*/
package com.njry.sjzl.busi.service.impl;import cn.hutool.core.date.DateTime;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.njry.config.FileProperties;
import com.njry.sjzl.busi.attachment.domain.Attachment;
import com.njry.sjzl.busi.attachment.domain.vo.AttachmentQueryCriteria;
import com.njry.sjzl.busi.attachment.mapper.AttachmentMapper;
import com.njry.sjzl.busi.domain.Inventory;
import com.njry.sjzl.busi.domain.InventoryAuth;
import com.njry.sjzl.busi.domain.InventoryDownloadLog;
import com.njry.sjzl.busi.domain.vo.InventoryQueryCriteria;
import com.njry.sjzl.busi.mapper.AtomBusiCategoryMapper;
import com.njry.sjzl.busi.mapper.InventoryAuthMapper;
import com.njry.sjzl.busi.mapper.InventoryMapper;
import com.njry.sjzl.busi.task.GenerateExcelTask;
import com.njry.sjzl.busi.task.vo.TransferVo;
import com.njry.utils.*;
import lombok.RequiredArgsConstructor;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.njry.sjzl.busi.service.InventoryDownloadLogService;
import com.njry.sjzl.busi.domain.vo.InventoryDownloadLogQueryCriteria;
import com.njry.sjzl.busi.mapper.InventoryDownloadLogMapper;
import org.apache.poi.util.IOUtils;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;import java.io.File;
import java.io.FileInputStream;
import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.*;
import java.io.IOException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;/**
* @description 服务实现
* @author wj
* @date 2024-06-20
**/
@Service
@RequiredArgsConstructor
public class InventoryDownloadLogServiceImpl extends ServiceImpl<InventoryDownloadLogMapper, InventoryDownloadLog> implements InventoryDownloadLogService {private final InventoryDownloadLogMapper inventoryDownloadLogMapper;private final InventoryMapper inventoryMapper;private final AttachmentMapper attachmentMapper;private final FileProperties properties;//    递归查询所属资产private final AtomBusiCategoryMapper atomBusiCategoryMapper;@Overridepublic PageResult<InventoryDownloadLog> queryAll(InventoryDownloadLogQueryCriteria criteria, Page<Object> page){IPage<InventoryDownloadLog> all = inventoryDownloadLogMapper.findAll(criteria, page);List<InventoryDownloadLog> records = all.getRecords();//        根据每条数据类的busiSort递归向下查找归属业务分类(回显)if(records.size() > 0 ){for (int i = 0; i < records.size(); i++) {Set<String> taskSetResult  = new LinkedHashSet<>();Long categoryId = records.get(i).getCategoryId();if(categoryId != null){List<String> subCategory = atomBusiCategoryMapper.findSubCategory(categoryId);String currentCategoryName = atomBusiCategoryMapper.findCategoryNameByCateforyId(categoryId);taskSetResult.addAll(subCategory);taskSetResult.add(currentCategoryName);String temp = "";for(String item : taskSetResult){temp += ","+item;}String result = temp.substring(1);records.get(i).setCategoryName(result);}}}return PageUtil.toPage(all);}@Overridepublic List<InventoryDownloadLog> queryAll(InventoryDownloadLogQueryCriteria criteria){return inventoryDownloadLogMapper.findAll(criteria);}@Override@Transactional(rollbackFor = Exception.class)public void create(InventoryDownloadLog resources) {
//        前端发起只传inventoryId,别的基本数据这里查完赋值Long inventoryId = resources.getInventoryId();Inventory inventory = inventoryMapper.queryDetailByInventoryId(inventoryId);resources.setInventoryName(inventory.getInventoryName());resources.setCategoryId(inventory.getCategoryId());//        新增的时候把操作人和操作时间Timestamp timestamp = DateTime.now().toTimestamp();
//        String username = "System";
//        try {username = SecurityUtils.getCurrentUsername();}catch (Exception ignored){}
//        操作人resources.setOperId(SecurityUtils.getCurrentUserId());resources.setOperDate(timestamp);
//        状态：0 待生成  2 正在生成  1 数据生成完成resources.setStatus(2);
//        正在生成没有附件idresources.setAttachmentId("");Long seq = inventoryDownloadLogMapper.getSeq();resources.setId(seq);save(resources);
//        异步生成文件(查询数据转成excel文件)Long currentUserId = SecurityUtils.getCurrentUserId();//        获取系统定义的文件路径String dirPath = properties.getPath().getInventory();//系统文件路径下inventoryString separator = properties.getPath().getSeparator();//获取系统分隔符
//        /inventory/日期/Date currentDate = new Date();SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM");String currentYearMonth = formatter.format(currentDate);System.out.println(currentYearMonth);dirPath += currentYearMonth + separator;//        生成需要的参数加入队列TransferVo transferVo = new TransferVo();transferVo.setDirPath(dirPath);transferVo.setFileSuffix("xlsx");transferVo.setSeq(seq);transferVo.setInventoryId(inventoryId);transferVo.setSeparator(separator);
//        transferVo.setTableHead(tableHead);//费时间,放在异步里面
//        transferVo.setMaps(maps);//费时间,放在异步里面transferVo.setCurrentUserId(currentUserId);GenerateExcelTask.addDataList(transferVo);}//    @Override
//    @Transactional(rollbackFor = Exception.class)
//    public void update(InventoryDownloadLog resources) {
//        InventoryDownloadLog inventoryDownloadLog = getById(resources.getId());
//        inventoryDownloadLog.copy(resources);
//        saveOrUpdate(inventoryDownloadLog);
//    }@Override@Transactional(rollbackFor = Exception.class)public void deleteAll(List<Long> ids) {removeBatchByIds(ids);}@Overridepublic void download(List<InventoryDownloadLog> all, HttpServletResponse response) throws IOException {List<Map<String, Object>> list = new ArrayList<>();for (InventoryDownloadLog inventoryDownloadLog : all) {Map<String,Object> map = new LinkedHashMap<>();map.put("唯一标识  序列", inventoryDownloadLog.getLogId());map.put("清单ID", inventoryDownloadLog.getInventoryId());map.put("清单名称", inventoryDownloadLog.getInventoryName());map.put("归属业务类别   T_atom_busi_category.CATEGORY_ID", inventoryDownloadLog.getCategoryId());map.put("操作人", inventoryDownloadLog.getOperId());map.put("操作时间", inventoryDownloadLog.getOperDate());map.put("状态：0 发起任务  2 正在生成  1 数据生成完成", inventoryDownloadLog.getStatus());map.put("附件编号", inventoryDownloadLog.getAttachmentId());map.put("提醒手机号码", inventoryDownloadLog.getMobile());list.add(map);}FileUtil.downloadExcel(list, response);}//        将文件转成响应流给前端@Overridepublic void downloadFile(String attachmentId, HttpServletResponse response) throws IOException {
//        根据文件id查找文件所在位置   文件名String fileName = "";String dirPath = "";String separator = properties.getPath().getSeparator();//获取系统分隔符AttachmentQueryCriteria attachmentQueryCriteria = new AttachmentQueryCriteria();attachmentQueryCriteria.setAttachmentId(attachmentId);Attachment attachment = attachmentMapper.queryAllWithCondition(attachmentQueryCriteria);if(attachment != null){dirPath = attachment.getAttachmentPath();fileName = attachment.getFileName();}
//        因为保存的时候是在默认路径下加一个watermarkPath文件夹下生成同名的文件,这里取得时候也得取水印的文件String watermarkPath = dirPath + "watermarkPath" + separator;FileInputStream watermarkFileInput = null;//response为HttpServletResponse对象response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");//test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码response.setHeader("Content-Disposition", "attachment;filename=file.xlsx");ServletOutputStream out = response.getOutputStream();File watermarkFile = new File(watermarkPath, fileName);watermarkFileInput = new FileInputStream(watermarkFile);IOUtils.copy(watermarkFileInput,out);watermarkFile.deleteOnExit();watermarkFileInput.close();}
}

生成的文件位置

/** */
package com.njry.config;import lombok.Data;
import com.njry.utils.ElConstant;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;/*** @author njry*/
@Data
@Configuration
@ConfigurationProperties(prefix = "file")
public class FileProperties {/** 文件大小限制 */private Long maxSize;/** 头像大小限制 */private Long avatarMaxSize;private ElPath mac;private ElPath linux;private ElPath windows;public ElPath getPath(){
//        System.getProperty() 方法用于获取系统属性的值String os = System.getProperty("os.name");if(os.toLowerCase().startsWith(ElConstant.WIN)) {return windows;} else if(os.toLowerCase().startsWith(ElConstant.MAC)){return mac;}return linux;}@Datapublic static class ElPath{private String path;private String avatar;private String inventory;private String separator;}
}

配置文件里写

# 文件存储路径
file:mac:path: ~/file/avatar: ~/avatar/inventory: /file/inventory/separator: /linux:path: /home/eladmin/file/avatar: /home/eladmin/avatar/inventory: /eladmin/file/inventory/separator: /windows:path: D:\sjzl\file\avatar: D:\sjzl\avatar\
#    inventory: D:\sjzl\file\inventory\ ## 不设置固定路径,相对路径自动找到项目所在盘位置inventory: \sjzl\file\inventory\separator: \# 文件大小 /MmaxSize: 100avatarMaxSize: 5

mapper层

/*
* 
*/
package com.njry.sjzl.busi.mapper;import com.njry.sjzl.busi.domain.InventoryDownloadLog;
import com.njry.sjzl.busi.domain.vo.InventoryDownloadLogQueryCriteria;
import java.util.List;
import java.util.Map;import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Mapper;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;/**
* @author wj
* @date 2024-06-20
**/
@Mapper
public interface InventoryDownloadLogMapper extends BaseMapper<InventoryDownloadLog> {IPage<InventoryDownloadLog> findAll(@Param("criteria") InventoryDownloadLogQueryCriteria criteria, Page<Object> page);List<InventoryDownloadLog> findAll(@Param("criteria") InventoryDownloadLogQueryCriteria criteria);List<String> findTableHead(@Param("tableName") String tableName,@Param("owner")  String owner);List<Map<String, Object>> commonSql(@Param("selectColumnSql") String selectColumnSql,@Param("tableName") String tableName,@Param("whereSql") String whereSql);Long getSeq();
}

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.njry.sjzl.busi.mapper.InventoryDownloadLogMapper"><resultMap id="BaseResultMap" type="com.njry.sjzl.busi.domain.InventoryDownloadLog"><result column="LOG_ID" property="logId"/><result column="LOG_ID" property="id"/><result column="INVENTORY_ID" property="inventoryId"/><result column="INVENTORY_NAME" property="inventoryName"/><result column="CATEGORY_ID" property="categoryId"/><result column="OPER_ID" property="operId"/><result column="OPER_NAME" property="operName"/><result column="OPER_DATE" property="operDate"/><result column="STATUS" property="status"/><result column="ATTACHMENT_ID" property="attachmentId"/><result column="MOBILE" property="mobile"/></resultMap><sql id="Base_Column_List">LOG_ID, INVENTORY_ID, INVENTORY_NAME, CATEGORY_ID, OPER_ID, OPER_DATE, STATUS, ATTACHMENT_ID, MOBILE</sql><sql id="Prefix_Base_Column_List">tidl.LOG_ID, tidl.INVENTORY_ID, tidl.INVENTORY_NAME, tidl.CATEGORY_ID, tidl.OPER_ID, tidl.OPER_DATE, tidl.STATUS, tidl.ATTACHMENT_ID, tidl.MOBILE</sql><select id="findAll" resultMap="BaseResultMap">select tuser.name OPER_NAME,<include refid="Prefix_Base_Column_List"/>from T_INVENTORY_DOWNLOAD_LOG tidlleft join T_USER tuser on tuser.user_id = tidl.OPER_ID<where><if test="criteria.inventoryId != null">and tidl.INVENTORY_ID = #{criteria.inventoryId}</if><if test="criteria.inventoryName != null">and tidl.INVENTORY_NAME like concat('%'||#{criteria.inventoryName},'%')</if><if test="criteria.status != null">and tidl.STATUS = #{criteria.status}</if><if test="criteria.mobile != null">and tidl.MOBILE = #{criteria.mobile}</if></where></select><select id="findTableHead" resultType="java.lang.String">select a.column_name from all_tab_cols awhere a.table_name=upper(#{tableName}) and owner=#{owner} order by a.column_id</select><select id="commonSql" resultType="java.util.Map">select ${selectColumnSql} from ${tableName}<if test="whereSql != ''">where ${whereSql}</if></select><select id="getSeq" resultType="java.lang.Long">select  seq_T_INVENTORY_DOWNLOAD_LOG.nextval user_user_id from dual</select>
</mapper>

自己定义了一个任务调度然后可以启动调度
在这里插入图片描述

package com.njry.sjzl.busi.task;import cn.hutool.core.date.DateTime;
import com.njry.sjzl.busi.attachment.domain.Attachment;
import com.njry.sjzl.busi.attachment.mapper.AttachmentMapper;
import com.njry.sjzl.busi.domain.Inventory;
import com.njry.sjzl.busi.domain.InventoryAuth;
import com.njry.sjzl.busi.domain.InventoryDownloadLog;
import com.njry.sjzl.busi.mapper.InventoryAuthMapper;
import com.njry.sjzl.busi.mapper.InventoryDownloadLogMapper;
import com.njry.sjzl.busi.mapper.InventoryMapper;
import com.njry.sjzl.busi.task.vo.TransferVo;
import com.njry.utils.GenerateExcelToFile;
import com.njry.utils.SecurityUtils;
import lombok.RequiredArgsConstructor;
import org.springframework.security.core.context.SecurityContext;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Service;import java.io.IOException;
import java.sql.Timestamp;
import java.util.ArrayDeque;
import java.util.List;
import java.util.Map;
import java.util.Queue;@Service
@RequiredArgsConstructor
public class GenerateExcelTask {/*** 定义一个队列*/// 定义一个队列static Queue<TransferVo> queue = new ArrayDeque<>();private final AttachmentMapper attachmentMapper;private final InventoryDownloadLogMapper inventoryDownloadLogMapper;private final InventoryAuthMapper inventoryAuthMapper;private final InventoryMapper inventoryMapper;public static void addDataList(TransferVo transferVo){queue.offer(transferVo);}public static TransferVo pollDataList(){TransferVo poll = queue.poll();// poll 方法用于获取队列头部的元素并移除它return poll;}public void run(){System.out.println("在sjzl-busi下面的bean被任务调度");
//        异步生成exceltry {TransferVo transferVo = GenerateExcelTask.pollDataList();System.out.println("取出一个数据后队列长度:"+queue.size());if(transferVo != null){String dirPath = transferVo.getDirPath();
//                List<Map<String, Object>> maps = transferVo.getMaps();
//                List<String> tableHead = transferVo.getTableHead();String fileSuffix = transferVo.getFileSuffix();Long seq = transferVo.getSeq();Long currentUserId = transferVo.getCurrentUserId();Long inventoryId = transferVo.getInventoryId();String separator = transferVo.getSeparator();
//        根据清单inventoryId和当前用户判断拥有的权限(要不要放where条件)  清单用户权限T_INVENTORY_AUTH
//        AUTH_TYPE  权限类别：1 全量 不放where  2 单元 (清单选择的列名和权限里的单元编号作为where条件)
//        AREA_ID    单元编号InventoryAuth inventoryAuth = inventoryAuthMapper.findByUserIdAndInventoryId(currentUserId, inventoryId);Inventory inventory = inventoryMapper.queryDetailByInventoryId(inventoryId);Integer authType = inventoryAuth.getAuthType();Long areaId = inventoryAuth.getAreaId();String whereSql = "";if(authType == 2){String queryColName = inventory.getQueryColName();whereSql = queryColName + "=" + areaId;}String tableName = inventory.getTableName();
//        tableName = "t_organization";//写死测试
//                tableName = "atom_base_info";//写死测试分sheet
//                whereSql = "";//写死测试(配置的列名称不对)String owner = "NJDATA";//从配置里读取//        获取表的列名-------作为select  xxx,xxx,xxx,xxx from 表名
//        select a.column_name from all_tab_cols a
//        where a.table_name=upper('t_organization') and owner='NJDATA' order by a.column_id;List<String> tableHead = inventoryDownloadLogMapper.findTableHead(tableName, owner);String selectColumnSql = String.join(",",tableHead);//      通用查询sql,传入查询字段,表名和where条件(区分#{}和${}的时候了)List<Map<String, Object>> maps = inventoryDownloadLogMapper.commonSql(selectColumnSql, tableName, whereSql);//             将数据生成excel文件里面Map<String, Object> resultMap = GenerateExcelToFile.dataToExcel(maps, tableHead, dirPath, fileSuffix,separator);Attachment attachment = new Attachment();
//            将文件数据保存文件附件表 T_ATTACHMENTattachment.setAttachmentId(resultMap.get("attachmentId").toString());attachment.setFileName(resultMap.get("fileName").toString());attachment.setFileType(resultMap.get("fileType").toString());attachment.setFileExtension(resultMap.get("fileExtension").toString());attachment.setFileSize(resultMap.get("fileSize").toString());attachment.setAttachmentPath(resultMap.get("attachmentPath").toString());//        新增的时候把操作人和操作时间Timestamp timestampAgain = DateTime.now().toTimestamp();attachment.setOperDate(timestampAgain);//        操作人
//                SecurityContext context = SecurityContextHolder.getContext();
//                System.out.println("SecurityContext:这里可以获取到吗"+context);
//                attachment.setOperId(SecurityUtils.getCurrentUserId());attachment.setOperId(currentUserId);attachmentMapper.insert(attachment);
//            在文件生成记录T_INVENTORY_DOWNLOAD_LOG 修改文件生成状态 和添加附件编号InventoryDownloadLog inventoryDownloadLog = new InventoryDownloadLog();inventoryDownloadLog.setId(seq);inventoryDownloadLog.setAttachmentId(resultMap.get("attachmentId").toString());inventoryDownloadLog.setStatus(1);inventoryDownloadLogMapper.updateById(inventoryDownloadLog);//            发送短信通知用户生成结束}else{
//            这里应该降低任务执行调度的频率System.out.println("暂时没有可以执行的生成文件");}} catch (IOException e) {e.printStackTrace();}}
}

工具类(将数据库数据转成file保存)

package com.njry.utils;import cn.hutool.core.util.IdUtil;
import com.njry.config.FileProperties;
import com.njry.exception.BadRequestException;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;public class GenerateExcelToFile {/**** @param list  数据库查询出来的信息* @param tableHead  数据库的表头(简单表头)* @param dirPath  保存的文件路径* @param fileSuffix 生成的excel格式后缀* @param separator 生成的excel带水印格要多加一层文件路径* @throws IOException*/public static Map<String, Object> dataToExcel(List<Map<String, Object>> list,List<String> tableHead,String dirPath, String fileSuffix, String separator) throws IOException {Map<String, Object> resultMap = new HashMap<>();Workbook wb = null;FileInputStream tempInput = null;String watermarkPath = dirPath + "watermarkPath" + separator;int type = 3;//默认用type区分一个sheet有多少行if("xlsx".equals(fileSuffix)){wb = new XSSFWorkbook();type = 1;}if("xls".equals(fileSuffix)){wb = new HSSFWorkbook();type = 2;}Workbook exportWorkbook = export(wb, list, tableHead, type);String attachmentId = IdUtil.simpleUUID();String fileSize = "";String to_file_name = attachmentId + "." + fileSuffix;	// 结果文件名称
//        判断保存的文件路径是否存在,不存在就创建File outFileExist = new File(dirPath);if(!outFileExist.exists()){outFileExist.mkdirs();}File outFile = new File(dirPath, to_file_name);try {FileOutputStream outStream = new FileOutputStream(outFile);// 写入Workbook到文件exportWorkbook.write(outStream);
//            也可以通过流获取大小
//            long size = outStream.getChannel().size();// 强制刷新文件流，确保所有数据都被写入到文件中outStream.flush();// 获取文件对象File outputFile = new File(dirPath, to_file_name);long length = outputFile.length();fileSize =  length  + " bytes";outStream.close();} catch (Exception e) {throw new BadRequestException("导出结果文件异常：" + e);}//        将有数据的excel的文件再加水印File tempFile = new File(dirPath, to_file_name);tempInput = new FileInputStream(tempFile);XSSFWorkbook xSSFWorkbook = new XSSFWorkbook(tempInput);
//            将导出的数据加水印放到另一个文件watermarkPath里面File watermarkFileExist = new File(watermarkPath, to_file_name);PoiSecurity.addWatermarkToXlsx(new String[]{"test"},xSSFWorkbook,watermarkFileExist);xSSFWorkbook.close();tempInput.close();// 终止后删除临时文件tempFile.deleteOnExit();
//        处理文件信息返回resultMap.put("attachmentId",attachmentId);resultMap.put("fileName",to_file_name);resultMap.put("fileType","excel");resultMap.put("fileExtension",fileSuffix);resultMap.put("fileSize",fileSize);resultMap.put("attachmentPath",dirPath);return resultMap;}/**** @param wb 操作的Workbook* @param list 数据库查询出来的信息* @param tableHead 数据库的表头(简单表头)* @param type excel类型  xlsx  1   xls 2   -------区分sheet最大告诉* @return*/public static Workbook export(Workbook wb,List<Map<String, Object>> list, List<String> tableHead,int type) {HSSFWorkbook HSSwb = null;XSSFWorkbook XSSwb = null;
//        不定义sheet名字,自生成
//        Excel 2003及更早的版本中，行数上限是65,536行
//        2007开始，行数上限增加到了1,048,576行int maxRow = 49999;//去除一个表头行if(type == 1){maxRow = 1048575;//去除一个表头行XSSwb  = (XSSFWorkbook)wb;}if(type == 2){maxRow = 65535;//去除一个表头行HSSwb  = (HSSFWorkbook)wb;}maxRow = 49999;//去除一个表头行(无论啥格式默认都是50000一个sheet)
//        处理数据需要多少个sheetint size = list.size();int result = size / maxRow + 1;if(result == 0){result = 1;}
//        循环sheetfor (int i = 0; i < result; i++) {if(type == 1){XSSFSheet sheet = XSSwb.createSheet();//            处理每个sheet的表头XSSFRow row = sheet.createRow((short) 0);Cell cell = null;for (int j = 0; j < tableHead.size(); j++) {cell = row.createCell(j);
//                cell.setCellStyle(headStyle);cell.setCellValue(tableHead.get(j));}
//          写入数据for (int n = 0 + maxRow * i; n < maxRow * (i + 1); n++) {
//                判断数据list的大小是否大于要创建的行if(size - 1 >= n ){//下面list.get(n)就取不到数据,不应该继续创建行  size 14 get(n)时候 n只能到13row = sheet.createRow(n % maxRow + 1);Cell dataCell = null;for (int m = 0; m < tableHead.size(); m++) {dataCell = row.createCell(m);dataCell.setCellValue(StringUtils.notEmpty(list.get(n).get(tableHead.get(m))));}}}}if(type == 2){HSSFSheet sheet = HSSwb.createSheet();//            处理每个sheet的表头HSSFRow row = sheet.createRow((short) 0);Cell cell = null;for (int j = 0; j < tableHead.size(); j++) {cell = row.createCell(j);
//                cell.setCellStyle(headStyle);cell.setCellValue(tableHead.get(j));}
//          写入数据for (int n = 0 + maxRow * i; n < maxRow * (i + 1); n++) {
//                判断数据list的大小是否大于要创建的行if(size - 1 >= n ){//下面list.get(n)就取不到数据,不应该继续创建行  size 14 get(n)时候 n只能到13row = sheet.createRow(n % maxRow + 1);Cell dataCell = null;for (int m = 0; m < tableHead.size(); m++) {dataCell = row.createCell(m);dataCell.setCellValue(StringUtils.notEmpty(list.get(n).get(tableHead.get(m))));}}}}}return wb;}
}

工具类PoiSecurity(之前贴过)

package com.njry.utils;import java.awt.*;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.*;
import java.security.GeneralSecurityException;import javax.imageio.ImageIO;import org.apache.poi.ooxml.POIXMLDocumentPart;
import org.apache.poi.openxml4j.exceptions.InvalidFormatException;
import org.apache.poi.openxml4j.opc.OPCPackage;
import org.apache.poi.openxml4j.opc.PackageAccess;
import org.apache.poi.openxml4j.opc.PackagePartName;
import org.apache.poi.openxml4j.opc.PackageRelationship;
import org.apache.poi.openxml4j.opc.TargetMode;
import org.apache.poi.poifs.crypt.EncryptionInfo;
import org.apache.poi.poifs.crypt.EncryptionInfoBuilder;
import org.apache.poi.poifs.crypt.EncryptionMode;
import org.apache.poi.poifs.crypt.Encryptor;
import org.apache.poi.poifs.crypt.binaryrc4.BinaryRC4EncryptionInfoBuilder;
import org.apache.poi.poifs.crypt.binaryrc4.BinaryRC4Encryptor;
import org.apache.poi.poifs.filesystem.POIFSFileSystem;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.*;
import org.springframework.core.io.ClassPathResource;public class PoiSecurity {public static void addWatermarkToXlsx(String[] content,XSSFWorkbook xssfworkbook,File outfile) throws IOException{ByteArrayOutputStream bytestream = createWaterMark(content,300,250);
//		XSSFWorkbook下面有几个sheetint sheetsize = xssfworkbook.getNumberOfSheets();for(int index=0;index<sheetsize;index++){XSSFSheet sheet = xssfworkbook.getSheetAt(index);XSSFWorkbook workbook = sheet.getWorkbook();
//			bytestream.toByteArray()(前置知识)
//			下面这一串看不懂(没看官网文档的下场)int pictureIdx = workbook.addPicture(bytestream.toByteArray(), Workbook.PICTURE_TYPE_PNG);POIXMLDocumentPart poixmlDocumentPart = workbook.getAllPictures().get(pictureIdx);PackagePartName ppn = poixmlDocumentPart.getPackagePart().getPartName();String relType = XSSFRelation.IMAGES.getRelation();PackageRelationship pr = sheet.getPackagePart().addRelationship(ppn, TargetMode.INTERNAL, relType, null);sheet.getCTWorksheet().addNewPicture().setId(pr.getId());}if(!outfile.exists()){File par = outfile.getParentFile();if(!par.exists()){par.mkdirs();}outfile.createNewFile();}FileOutputStream out = new FileOutputStream(outfile);xssfworkbook.write(out);out.close();}public static void addImageToXlsx(String[] content,XSSFWorkbook xssfworkbook,File outfile) throws IOException{int imgW = 300,imgH = 250;ByteArrayOutputStream bytestream = createWaterMark(content,imgW,imgH);byte[] bytes = bytestream.toByteArray();int sheetsize = xssfworkbook.getNumberOfSheets();for(int index=0;index<sheetsize;index++){XSSFSheet sheet = xssfworkbook.getSheetAt(index);int[] wh = getSheetWidthAndHeight(sheet);int width = wh[0];int height = wh[1];XSSFDrawing drawingPatriarch = sheet.createDrawingPatriarch();//根据宽高进行插入for(int i = 0;i< (width / imgW) + 1;i++) {	//x轴for(int j = 0; j <( height / imgH) + 1;j++){	//y轴int x = i * imgW;int y = j * imgH;//根据图片插入/*XSSFClientAnchor anchor = new XSSFClientAnchor(x,y,x+width,y+height,0,0,1,1);int pIndex = xssfworkbook.addPicture(bytes, Workbook.PICTURE_TYPE_PNG);drawingPatriarch.createPicture(anchor,pIndex);*/}}}if(!outfile.exists()){File par = outfile.getParentFile();if(!par.exists()){par.mkdirs();}outfile.createNewFile();}FileOutputStream out = new FileOutputStream(outfile);xssfworkbook.write(out);out.close();}/*** 获取sheet的宽高* @param sheet* @return*/private static int[] getSheetWidthAndHeight(Sheet sheet){float height = 0f;float width = 0f;int firstRowNum = sheet.getFirstRowNum();int lastRowNum = sheet.getLastRowNum();for (int i = firstRowNum; i < lastRowNum; i++) {Row row = sheet.getRow(i);if(i == firstRowNum){	//获取宽度short firstCellNum = row.getFirstCellNum();short lastCellNum = row.getLastCellNum();for(int j = firstCellNum;j<lastCellNum;j++){width = width + sheet.getColumnWidthInPixels(j);}}height = height+ row.getHeightInPoints();}return new int[]{Math.round(width),Math.round(height)};}private static ByteArrayOutputStream createWaterMark(String[] content,int width,int height) throws IOException {ClassPathResource resource = new ClassPathResource("font/simsun.ttc");//宋体InputStream resourceAsStream = null;Font font = null;try{resourceAsStream = resource.getInputStream();font = Font.createFont(Font.TRUETYPE_FONT, resourceAsStream);font = font.deriveFont(20f);}catch (Exception e){throw new IOException("PoiSecurity createWaterMark error",e);} finally {if(resourceAsStream!=null){resourceAsStream.close();}}
//		(前置知识)BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);// 获取bufferedImage对象
//        设置字体(前置知识)Graphics2D g2d = image.createGraphics(); // 获取Graphics2d对象(前置知识)
//		这里实在看不懂,为啥销毁后用BufferedImage重新获取Graphics2d对象image = g2d.getDeviceConfiguration().createCompatibleImage(width, height, Transparency.TRANSLUCENT);g2d.dispose();g2d = image.createGraphics();g2d.setColor(new java.awt.Color(0, 0, 0, 40));//设置字体颜色和透明度，最后一个参数为透明度(前置知识)g2d.setStroke(new BasicStroke(1)); // 设置字体g2d.setFont(font); // 设置字体类型  加粗 大小g2d.rotate(-0.5, (double) image.getWidth() / 2, (double) image.getHeight() / 2);//设置倾斜度
//		要想得到表示屏幕设备字体属性的对象(前置知识)FontRenderContext context = g2d.getFontRenderContext();
//        循环设置水印文字位置(看不懂)for (int i = 0; i < content.length; i++) {
//        	返回包围字符串的矩形(前置知识)if(content[i] == null){continue;}Rectangle2D bounds = font.getStringBounds(content[i], context);
//            宽度double x = (width - bounds.getWidth()) / 2;
//            高度double y = (height - bounds.getHeight()) / 2;
//            上坡度double ascent = -bounds.getY();double baseY = y + ascent;// 写入水印文字原定高度过小，所以累计写水印，增加高度g2d.drawString(content[i], (int) x, (int) baseY+(30*i));}// 设置透明度(前置知识)
//        g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER));g2d.setComposite(AlphaComposite.getInstance(AlphaComposite.DST_OVER));// 释放对象g2d.dispose();
//		ByteArrayOutputStream(前置知识)ByteArrayOutputStream os = new ByteArrayOutputStream();
//		BufferedImage –> byte[](前置知识)ImageIO.write(image, "png", os);return os;}public static void encXlsx(String paasword,File file) throws InvalidFormatException, IOException, GeneralSecurityException{try (POIFSFileSystem fs = new POIFSFileSystem()) {EncryptionInfo info = new EncryptionInfo(EncryptionMode.agile);// EncryptionInfo info = new EncryptionInfo(EncryptionMode.agile, CipherAlgorithm.aes192, HashAlgorithm.sha384, -1, -1, null);Encryptor enc = info.getEncryptor();enc.confirmPassword(paasword);// Read in an existing OOXML file and write to encrypted output stream// don't forget to close the output stream otherwise the padding bytes aren't addedtry (OPCPackage opc = OPCPackage.open(file, PackageAccess.READ_WRITE);OutputStream os = enc.getDataStream(fs)) {opc.save(os);}// Write out the encrypted versiontry (FileOutputStream fos = new FileOutputStream(file)) {fs.writeFilesystem(fos);}}}}

本文来自互联网用户投稿，该文观点仅代表作者本人，不代表本站立场。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如若转载，请注明出处：http://www.mzph.cn/web/39524.shtml

如若内容造成侵权/违法违规/事实不符，请联系多彩编程网进行投诉反馈email:809451989@qq.com，一经查实，立即删除！

相关文章

iPhone白苹果怎么修复？4个方法解决你的烦恼！

iPhone白苹果怎么修复？4个方法解决你的烦恼！

其实iPhone手机出现“白苹果”这事&#xff0c;如果是iPhone轻度用户&#xff0c;可能大家一辈子都不会遇到一次。但如果是iPhone重度用户、越狱爱好者、软件收集狂&#xff0c;可能就会遇到了。 白苹果&#xff0c;一般指iOS设备出现软、硬件故障&#xff0c;卡在一个类似于启…
阅读更多...
EVM-MLIR：以MLIR编写的EVM

EVM-MLIR：以MLIR编写的EVM

1. 引言 EVM_MLIR&#xff1a; 以MLIR编写的EVM。 开源代码实现见&#xff1a; https://github.com/lambdaclass/evm_mlir&#xff08;Rust&#xff09; 为使用MLIR和LLVM&#xff0c;将EVM-bytecode&#xff0c;转换为&#xff0c;machine-bytecode。LambdaClass团队在2周…
阅读更多...
Entity Framework EF Migration 迁移

Entity Framework EF Migration 迁移

针对Code First来说关注的只有实体类。当需求变更时只需要添加新的实体类或者在实体类中添加、删除、修改属性即可。但是修改完成之后要如何将修改同步到数据库中&#xff1f; migration 机制就出现了 ●启用Migrations 　　●通过Add-Migration添加Migration 　　●Update-D…
阅读更多...
k8s kubectl top pod报错error Metrics API not available

k8s kubectl top pod报错error Metrics API not available

文章目录 1、场景2、解决方法1、确认Metrics Server是否已经在集群中安装2、安装metric-server组件2.1、组件地址2.2、组件与K8S集群版本对应关系2.3、apply资源清单文件2.4、验证Metrics Server正常工作 1、场景 在使用kubectl top pod 命令时遇到了error: Metrics API not a…
阅读更多...
大语言模型融合知识图谱的问答系统研究

大语言模型融合知识图谱的问答系统研究

文章目录 题目摘要方法实验消融实验 题目 大语言模型融合知识图谱的问答系统研究 论文地址&#xff1a;http://fcst.ceaj.org/CN/10.3778/j.issn.1673-9418.2308070 项目地址&#xff1a;https://github.com/zhangheyi-1/llmkgqas-tcm/ 摘要 问答系统&#xff08;Question Ans…
阅读更多...
【持续更新】vs 编译过程中的问题及其解决方案

【持续更新】vs 编译过程中的问题及其解决方案

独立寒秋&#xff0c;湘江北去&#xff0c;橘子洲头。 目录 问题 1 &#xff1a; 无法查看或者打开 PDB 文件。 问题 2 &#xff1a; 命令提示符中查看运行结果&#xff0c;控制台闪退。 问题 3 &#xff1a; 某功能的判断条件&#xff1a;int val > 1e9&#xff0c;逻辑…
阅读更多...
领导高水平，在管人上都会做这3点，让下属忠心耿耿

领导高水平，在管人上都会做这3点，让下属忠心耿耿

领导高水平&#xff0c;在管人上都会做这3点&#xff0c;让下属忠心耿耿 第一点&#xff1a;给到有面子 作为一个领导&#xff0c;一定要在另一方面给自己的下属做最大努力的争取&#xff0c;只有把利益给到位&#xff0c;让你的下属有面子&#xff0c;才能够真正的赢得下属的心…
阅读更多...
命令行运行git reflog（reference log）报错的解决办法

命令行运行git reflog（reference log）报错的解决办法

文章目录 1. 检查 Git 是否已安装2. 检查 PATH 环境变量3. 重新安装 Git 在Git中&#xff0c; reflog的英文全称是 “ reference log”。意思是 引用日志&#xff08;参考日志&#xff09;。它记录了本地仓库中HEAD和分支引用所指向的提交的变更历史。这包括了你所有的提交&…
阅读更多...
澳大利亚新闻.科技.汽车.旅行.商业类单发媒体

澳大利亚新闻.科技.汽车.旅行.商业类单发媒体

每日简报Daily Bulletin 澳大利亚西部时间ModernAustralian.com 澳大利亚垂直新闻.科技.汽车.旅行.商业类媒体&#xff0c;ModernAustralian.com是澳大利亚西部地区的一家权威媒体平台&#xff0c;提供全面的新闻报道、科技资讯、汽车信息、旅行指南、商业动态等内容。每日简报…
阅读更多...
liunx文件系统，日志分析

liunx文件系统，日志分析

文章目录 1.inode与block1.1 inode与block概述1.2 inode的内容1.3 文件存储1.4 inode的大小1.5 inode的特殊作用 2.硬链接与软链接2.1链接文件分类 3.恢复误删除的文件3.1 案例:恢复EXT类型的文件3.2 案例:恢复XFS类型的文件3.2.1 xfsdump使用限制 4.分析日志文件4.1日志文件4.…
阅读更多...
element-ui Tree之懒加载叶子节点强制设置父级半选效果

element-ui Tree之懒加载叶子节点强制设置父级半选效果

效果&#xff1a; 前言&#xff1a; 我们是先只展示一级的&#xff0c;二级的数据是通过点击之后通过服务器获取数据&#xff0c;并不是全量数据直接一起返回回来的。 问题&#xff1a; 当你设置了默认选中的子节点&#xff0c;但是由于刚进入页面此时tree中数据暂是没有这个…
阅读更多...
A*——AcWing 179. 八数码

A*——AcWing 179. 八数码

A* 定义 A* 算法是一种在图形或地图中寻找最短路径的启发式搜索算法。它通过综合考虑起始节点到当前节点的实际代价和当前节点到目标节点的预估代价&#xff0c;来决定下一步的搜索方向。 运用情况 路径规划&#xff1a;如在地图导航中为车辆、行人规划最优路线。游戏开发&…
阅读更多...
学会python——用python制作一个登录和注册窗口（python实例十八）

学会python——用python制作一个登录和注册窗口（python实例十八）

目录 1.认识Python 2.环境与工具 2.1 python环境 2.2 Visual Studio Code编译 3.登录和注册窗口 3.1 代码构思 3.2 代码实例 3.3 运行结果 4.总结 1.认识Python Python 是一个高层次的结合了解释性、编译性、互动性和面向对象的脚本语言。 Python 的设计具有很强的可读…
阅读更多...
免杀笔记 ---＞ PE

免杀笔记 ---＞ PE

本来是想先把Shellcode Loader给更新了的&#xff0c;但是涉及到一些PE相关的知识&#xff0c;所以就先把PE给更了&#xff0c;后面再把Shellcode Loader 给补上。 声明&#xff1a;本文章内容来自于B站小甲鱼 1.PE的结构 首先我们要讲一个PE文件&#xff0c;就得知道它的结构…
阅读更多...
SPI四种模式--极性与相位

SPI四种模式--极性与相位

SPI的四种模式&#xff1a;相位和极性 极性 定义时钟空闲状态&#xff1a; CPOL0&#xff1a;时钟线在空闲状态为低电平 CPOL1&#xff1a;时钟线在空闲状态为高电平 这个设置决定了设备不进行通信时时钟线的状态。 兼容性&#xff1a; 不同的SPI设备可能需要不同的时钟极性…
阅读更多...
【Linux开发实战指南】基于TCP、进程数据结构与SQL数据库：构建在线云词典系统（含注册、登录、查询、历史记录管理功能及源码分享）

【Linux开发实战指南】基于TCP、进程数据结构与SQL数据库：构建在线云词典系统（含注册、登录、查询、历史记录管理功能及源码分享）

目录 项目演示&#xff1a; 1. 主界面 技术讲解&#xff1a; TCP连接 进程的并发 链表 SQLite3 IO对文件的读写 功能实现 实现逻辑 我遇到的问题&#xff1a; 服务器端代码思路解析 必要条件 步骤详解 客户端代码思路解析 步骤详解 服务器源码如下&#xff1a;…
阅读更多...
windows电脑如何运行python的定时任务

windows电脑如何运行python的定时任务

这里需要使用&#xff1a;windows系统设置-控制面板里的计划任务 1.打开计划任务之后&#xff0c;选择&#xff1a;创建基本任务 2.填写名称&#xff0c;这里根据自己具体的项目需求填写&#xff0c;然后点击下一步。 3.选择每日&#xff0c;再点击下一步 4.设置时间&…
阅读更多...
科普文：linux I/O原理、监控、和调优思路

科普文：linux I/O原理、监控、和调优思路

Linux 文件系统 磁盘和文件系统的关系&#xff1a; 磁盘为系统提供了最基本的持久化存储。 文件系统则在磁盘的基础上&#xff0c;提供了一个用来管理文件的树状结构。 文件系统工作原理 索引节点和目录项 文件系统&#xff0c;本身是对存储设备上的文件&#xff0c;进行…
阅读更多...
多维度多场景文档门户，鸿翼ECM文档云打造文档管理新范式

多维度多场景文档门户，鸿翼ECM文档云打造文档管理新范式

​在现代企业运营中&#xff0c;内容协作的效率直接影响到组织的整体表现和竞争力。传统的文档管理系统都是通过目录结构的方式进行文件管理&#xff0c;在实际业务中无法满足用户多视角、多维度、多场景的文档业务需求。因此&#xff0c;搭建结合文档体系的业务门户是许多企业…
阅读更多...
策略模式入门：基本概念与应用

策略模式入门：基本概念与应用

目录 策略模式策略模式结构策略模式应用场景策略模式优缺点练手题目题目描述输入描述输出描述题解 策略模式 策略模式&#xff0c;又称政策模式&#xff0c;是一种行为型设计模式&#xff0c;它能让你定义一系列算法&#xff0c;并将每种算法分别放入独立的类中&#xff0c;以…
阅读更多...
推荐文章
最新文章

Copyright @ 2022~2023