SpringBoot文件下载（1）——生成下载

素颜马尾好姑娘i 2023-02-21 09:07 184阅读 0赞

1）.引入Excel工具类，在pom.xml中输入：

<dependency>
                <groupId>com.sargeraswang.util</groupId>
                <artifactId>excel-util</artifactId>
                <version>1.2.1</version>
            </dependency>
            <dependency>
                <groupId>org.apache.poi</groupId>
                <artifactId>poi-ooxml</artifactId>
                <version>3.9</version>
            </dependency>
            <dependency>
                <groupId>org.apache.poi</groupId>
                <artifactId>poi</artifactId>
                <version>3.9</version>
            </dependency>

2).新建.Java文件:HandleFile

package com.tfjybj.rbac.util;
    
    import org.apache.poi.hssf.usermodel.*;
    import org.apache.poi.ss.usermodel.HorizontalAlignment;
    
    import javax.servlet.http.HttpServletResponse;
    import java.io.FileOutputStream;
    import java.io.OutputStream;
    import java.net.URLEncoder;
    import java.util.List;
    import java.util.Map;
    
    public class HandleFile{
    
        /**
         * Excel内容设置
         *
         * @param excelMap
         */
        public static HSSFWorkbook createExcel(Map<String, Object> excelMap) {
    
            HSSFWorkbook workbook = new HSSFWorkbook();
            String sheetName = excelMap.get("sheetName").toString();
            HSSFSheet sheet = workbook.createSheet(sheetName);
    
            //只考虑一个sheet的情况
            HSSFRow row = sheet.createRow(0);
            //设置列宽，setColumnWidth的第二个参数要乘以256，这个参数的单位是1/256个字符宽度
            sheet.setColumnWidth(1, 12 * 256);
            sheet.setColumnWidth(3, 17 * 256);
    
            //表头设置为居中加粗
            HSSFCellStyle style = workbook.createCellStyle();
            HSSFFont font = workbook.createFont();
            font.setBold(true);
    //        font.setBoldweight((short) 14);
            style.setAlignment(HorizontalAlignment.CENTER);
            style.setFont(font);
            //是否生成序号，序号从1开始
            boolean isSerial = (boolean) excelMap.get("isSerial");
            //获取表头列表
            List<String> headerList = (List<String>) excelMap.get("header");
            HSSFCell cell;
    
            //生成表头
            int headRow=0;
            if (isSerial){
                //设置第一个列为序号列
                cell = row.createCell(0);
                cell.setCellValue("序号");
                cell.setCellStyle(style);
                headRow = 1;
    
            }
            for (String header : headerList) {
                cell = row.createCell(headRow);
                cell.setCellValue(header);
                cell.setCellStyle(style);
                headRow++;
            }
    
            //往Excel中插入数据
            List<List<String>> data = (List<List<String>>) excelMap.get("data");
    
            int rowNum = 1;
            //需要生成序号
            if (isSerial){
                //表头字段包含序号一列
                int headSize = headerList.size() + 1;
                for (List<String> obj:data){
                    HSSFRow currRow = sheet.createRow(rowNum);
                    for (int i=1;i<headSize;i++){
                        currRow.createCell(0).setCellValue(rowNum);
                        currRow.createCell(i).setCellValue(obj.get(i-1));
                    }
                    rowNum++;
                }
                //无需生成序号
            }else{
                int headSize = headerList.size();
                for (List<String> obj:data){
                    HSSFRow currRow = sheet.createRow(rowNum);
                    for (int i=0;i<headSize;i++){
                        currRow.createCell(i).setCellValue(obj.get(i));
                    }
                    rowNum++;
                }
            }
    
            return workbook;
        }
    
        /**
         * 生成excel文件
         *
         * @param filename
         * @param workbook
         * @throws Exception
         */
        public static void buildExcelFile(String filename, HSSFWorkbook workbook) throws Exception {
            FileOutputStream fos = new FileOutputStream(filename);
            workbook.write(fos);
            fos.flush();
            fos.close();
        }
    
        /**
         * 浏览器下载excel
         *
         * @param filename
         * @param workbook
         * @param response
         * @throws Exception
         */
        public static void buildExcelDocument(String filename, HSSFWorkbook workbook, HttpServletResponse response) throws Exception {
            response.setContentType("application/vnd.ms-excel");
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(filename, "utf-8"));
            OutputStream outputStream = response.getOutputStream();
            workbook.write(outputStream);
            outputStream.flush();
            outputStream.close();
        }
    
    
    }

3）.主要代码

@GetMapping(value = "/createExcel")
        public String createExcel(HttpServletResponse response) throws Exception {
            //定义excelMap，存放excel中的信息
            Map<String, Object> excelMap = new HashMap<>();
            // 1.设置Excel表头
            List<String> headerList = new ArrayList<>();
            headerList.add("user_code");
            headerList.add("姓名");
            headerList.add("邮件");
            headerList.add("手机号");
            excelMap.put("header", headerList);
    
            // 2.是否需要生成序号，序号从1开始(true-生成序号 false-不生成序)
            excelMap.put("isSerial", false);
    
            // 3.sheet名
            String sheetName = "用户信息表";
            excelMap.put("sheetName", sheetName);
    
    
            // 4.需要放入Excel中的数据
            List<User> rows = new ArrayList<>();
            // 实例化用户
            User tempUser = new User();
            // 给用户添加属性值
            tempUser.setUserCode("17716577777");
            tempUser.setName("张三");
            tempUser.setEmail("zhangsan@163.com");
            tempUser.setPhone("17712331222");
            rows.add(tempUser);
    
            List<List<String>> data = new ArrayList<>();
    
            for (User user : rows) {
                // 所有的数据顺序必须和表头一一对应
                // list存放每一行的数据（让所有的数据类型都转换成String，这样就无需担心Excel表格中数据不对）
                List<String> list = new ArrayList<>();
                list.add(String.valueOf(user.getUserCode()));
                list.add(String.valueOf(user.getName()));
                list.add(String.valueOf(user.getEmail()));
                list.add(String.valueOf(user.getPhone()));
                //data存放全部的数据
                data.add(list);
            }
            excelMap.put("data", data);
    
            //Excel文件内容设置
            HSSFWorkbook workbook = HandleFile.createExcel(excelMap);
            //文件名
            String fileName = "Excel.xls";
    
            //生成excel文件
            HandleFile.buildExcelFile(fileName, workbook);
    
            //浏览器下载excel
            HandleFile.buildExcelDocument(fileName, workbook, response);
    
            return "down excel";
    
        }

各块代码的功能：

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