一 操作案例

1.1 pom文件

        <dependency>
            <groupId>net.sf.jett</groupId>
            <artifactId>jett-core</artifactId>
            <version>0.11.0</version>
        </dependency>

1.2 代码

 /**
   * @author liujianfu
   * @description       导出 环保指标查询日，月，年数据
   * @date 2022/12/1 16:39
   * @param [response]
   * @return void
   */
    @RequestMapping("/export")
    public void  exportEnvCycleExcel(HttpServletResponse response) {
        Map<String, Object> resultMap = new HashMap<String, Object>();
        resultMap.put("titleName","环保指标报表");
        resultMap.put("reportDate", DateUtils.dateToStr(new Date(),"yyyy-MM-dd"));
        //List<Student> studentsList=new ArrayList<>();
          List<Map> studentsList=new ArrayList<>();
        for(int k=0;k<5;k++){
            Map<String,Object> map=new LinkedHashMap<>();
            map.put("id",k);
            map.put("name","李四"+k);
            map.put("age",(k+1)*2);
            studentsList.add(map);
        }
        resultMap.put("dataList",studentsList);
        buildExcelReport( resultMap, response);
    }



    /**
     * @author liujianfu
     * @description       封装excel
     * @date 2022/11/8 10:42
     * @param [resultMap]
     * @return void
     */
    public void  buildExcelReport(Map<String, Object> resultMap, HttpServletResponse response){
        String modelFile="d:/model-test.xlsx";
        try (InputStream is = new FileInputStream(new File(modelFile));) {
            Workbook workbook = new ExcelTransformer().transform(is, resultMap);
           buildExcelDocument("环保_"+System.currentTimeMillis()+".xlsx", workbook, response);


        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    /**
     * @author liujianfu
     * @description       数据流的输出
     * @date 2022/11/8 10:42
     * @param [filename, workbook, response]
     * @return void
     */
    protected static void buildExcelDocument(String filename, Workbook workbook, HttpServletResponse response)
            throws Exception {
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        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();
    }

1.3 excel模板

<jt:forEach items="${dataList}" var="t"> ${t.id}    ${t.name}   ${t.age}</jt:forEach>

1.4 导出效果