Elegant import and export Excel

Elegant import and export Excel

First, the configuration dependent pom, poi-ooxml version note is greater than or equal to less than 3.17 3.17,3.8 unavailable

    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>3.17</version>
    </dependency>
    <dependency>
        <groupId>cn.hutool</groupId>
        <artifactId>hutool-all</artifactId>
        <version>5.0.7</version>
    </dependency>

Excel then create corresponding Bean object:

    /**
     * @ClassName User
     * @Description TODO
     * @Author RickSun && iFillDream
     * @Date 2020/1/9 10:59
     * @Version 1.0
     */
    public class User {
    
        private String name;
    
        private Integer age;
    
        private String address;
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public Integer getAge() {
            return age;
        }
    
        public void setAge(Integer age) {
            this.age = age;
        }
    
        public String getAddress() {
            return address;
        }
    
        public void setAddress(String address) {
            this.address = address;
        }
    
        //我们重写了toString()方法
        @Override
        public String toString() {
            return "User{"  
                    "name='"   name   '\''  
                    ", age="   age  
                    ", address='"   address   '\''  
                    '}';
        }
    
        //创建构造方法时一定要创建一个空参构造器
        public User(String name, Integer age, String address) {
            this.name = name;
            this.age = age;
            this.address = address;
        }
    
        //空参构造器
        public User() {
            super();
        }
    }

Import Export tags as follows:

    package com.hmkj.ygyr.web.controller.pc;
    
    import cn.hutool.core.io.IoUtil;
    import cn.hutool.poi.excel.ExcelReader;
    import cn.hutool.poi.excel.ExcelUtil;
    import cn.hutool.poi.excel.ExcelWriter;
    
    import io.swagger.annotations.ApiOperation;
    import org.springframework.web.bind.annotation.*;
    
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServletResponse;
    import java.io.File;
    
    import java.util.*;
    
    
    
    @RestController
    @RequestMapping("/filldream/excel")
    public class PcAccountController{
    
        public static void main(String[] args)  {
            //导入Excel
            ExcelReader excelReader = ExcelUtil.getReader(new File("D:\\Pictures\\test\\filldream.xls"));
    //        ExcelUtil.getReader(InputStream); 也可通过流导入
            //读取为Map列表
            readToMap(excelReader);
            //读取为Bwan列表
            List<User> userList = readToBean(excelReader);
            //关闭
            excelReader.close();
            //导出到本地
            exportLocal(userList);
        }
    
        /**
         * 读取为Bean列表
         * @param excelReader
         * @return
         */
        public static List<User> readToBean(ExcelReader excelReader){
            System.out.println("----readToBean----");
            List<User> users = excelReader.readAll(User.class);
            users.forEach( user ->{
                System.out.println(user);
            });
            return users;
        }
    
    
        /**
         * 导出到本地
         * @param userList
         */
        public static void exportLocal(List<User> userList){
            // 通过工具类创建writer
            ExcelWriter writer = ExcelUtil.getWriter("D:\\Pictures\\test\\exportList.xlsx");
            // 一次性写出内容
            writer.write(userList);
            writer.setSheet("用户列表");
            // 关闭writer，释放内存
            writer.close();
        }
    
    
    
        @GetMapping("/export")
        @ApiOperation(value = "导出Excel")
        public void export(HttpServletResponse response)throws Exception {
            //初始化用户
            List<User> userList = new ArrayList<>(2);
            userList.add(new User("轻梦致新",2,"浙江"));
            userList.add(new User("轻梦致新",2,"杭州"));

            ServletOutputStream out = response.getOutputStream();
            ExcelWriter writer = new ExcelWriter(true,"用户表");
            writer.write(userList, true);
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
            response.setHeader("Content-Disposition","attachment;filename=ifilldream.xlsx");
            writer.flush(out, true);
            writer.close();
            IoUtil.close(out);
        }
    
    
        /**
         * 读取为Map列表
         * @param excelReader
         */
        public static void readToMap(ExcelReader excelReader){
            System.out.println("----readToMap----");
            List<Map<String, Object>> readAll = excelReader.readAll();
            for (Map<String, Object> map : readAll) {
                if(checkMap(map,"name")){
                    System.out.println(map.get("name").toString());
                }
                if(checkMap(map,"age")){
                    System.out.println(map.get("age").toString());
                }
                if(checkMap(map,"address")){
                    System.out.println(map.get("address").toString());
                }
            }
        }
    
        /**
         * 检验map是否含有指定字段
         * @param map
         * @param fieldName
         * @return
         */
        public static Boolean checkMap(Map<String, Object> map,String fieldName){
            return map.containsKey(fieldName) && map.get(fieldName) != null;
        }
    
    }

Download the file corruption problem solving tips have damage in accordance with user feedback after code generation download prompt Excel file can not be opened, after investigation, it may be a few questions:

(1) writer not properly closed and the flow out, increase the closed end of the code in the finally block. (2) extension mismatch. getWriter generated by default xls, Content-Disposition also should be xls, getWriter only if (true) can be used xlsx (3) Maven project stored in Excel (under src / main / resources) ClassPath in macro substitution result in damage to solve is to add filtering (reference: https: //blog.csdn.net/qq_42270377/article/details/92771349) (4) Excel file corruption prompt open, WPS can be opened. This is the Excel security control caused the solution, see: https: //blog.csdn.net/zm9898/article/details/99677626 In addition, you can also import so Excel:

@ApiOperation(value = "写入数据")
@PostMapping(value = "/readExcel")
public BaseResponse<Void> readExcel(@RequestParam(value = "file", required = true) MultipartFile file) throws IOException {
    /**
     * TODO do something
     * 可以使用以下方式导入
     */
    ExcelReader reader = ExcelUtil.getReader(file.getInputStream());
    /**
     * TODO do something
     */
    return new BaseResponse();
}

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