使用Java反射 泛型做一个导出excel通用工具类

前两天做了一个导出excel的功能,当时图省事就用了公司的框架直接导了,后来上线以后客户反应说导出的excel文件打不开,原因居然是office不兼容,WPS兼容,所以我就用poi写了一个
下面展示一些 内联代码片。

 // 封装excel
        HSSFWorkbook hssfWorkbook = new HSSFWorkbook();
        HSSFSheet sheet = hssfWorkbook.createSheet("流程台账");
        Row row = sheet.createRow(0);
        //设置标题
        if (row != null) {
            row.createCell(0).setCellValue("流程ID");
            row.createCell(1).setCellValue("需求编号");
            row.createCell(2).setCellValue("标题");
            row.createCell(3).setCellValue("当前节点");
            row.createCell(4).setCellValue("当前审批人");
            row.createCell(5).setCellValue("申请人");
            row.createCell(6).setCellValue("联系电话");
            row.createCell(7).setCellValue("申请日期");
            row.createCell(8).setCellValue("申请人部门");
            row.createCell(9).setCellValue("申请人科室");
            row.createCell(10).setCellValue("当前应用系统");
        

           if (allProcessaccounts != null && allProcessaccounts.size() > 0) {
            for (int i = 0; i < allProcessaccounts.size(); i++) {
                ImdDemandProcessaccounts p = allProcessaccounts.get(i);
                rowIndex++;
                Row rowF = sheet.createRow(rowIndex);
                // 添加第一层
                rowF.createCell(0).setCellValue(p.getHeadDocumentId());
                rowF.createCell(1).setCellValue(p.getDocNum());
                rowF.createCell(2).setCellValue(p.getDemTitle());
                rowF.createCell(3).setCellValue(p.getNodeName());
                rowF.createCell(4).setCellValue(p.getApproveUserName());
                rowF.createCell(5).setCellValue(p.getEmployeeName());
                rowF.createCell(6).setCellValue(p.getTelPhone());
                rowF.createCell(7).setCellValue(p.getApplyDate());
                rowF.createCell(8).setCellValue(p.getOrgName());
                rowF.createCell(9).setCellValue(p.getOrganizeAllName());
                rowF.createCell(10).setCellValue(p.getCutSystem());

这种方法虽然简单,但是不够复用,属于硬编码,我后来又有一些大量导出excel的需求,我就决定来写个工具类了,设计了半天,决定用Java特性反射和泛型来做,上代码

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface Details {
	//详情
    String value();
    //是否导出
    boolean isExport();
}

@Data
@Table(value = "EXTICT_INFO_QUERY_V")
public class ExtictInfoQuery extends MpaasBasePojo {

    @Details(value = "出门证单号",isExport = true)
    @Style(displayName = "出门证单号", width = "25")
    @Column(value = "DOC_NUMBER")
    private String docNumber;

    @Details(value = "DOCUMENT_ID",isExport = true)
    @Column(value = "DOCUMENT_ID")
    private Long documentId;

    @Details(value = "资产所属单位/发货单位",isExport = true)
    @Style(displayName = "资产所属单位/发货单位", width = "25")
    @Column(value = "ASSETS_AFF_UNIT")
    private String assetsAffUnit;

public class ExportUtil <T>{
    public void exportDate2(Object o, List<T> allProcessaccounts, HttpServletResponse response) {
        try {
            HSSFWorkbook wb = getHSSFWorkbook(o, allProcessaccounts, response);
            if (wb == null) {
                return;
            }
            //写入response
            response.reset();
            response.setContentType("application/vnd.ms-excel;charset=utf-8");
            response.addHeader("Content-Disposition", "attachment; filename=" + URLEncoder.encode("excel.xls", "UTF8"));
            ServletOutputStream fileOut = response.getOutputStream();
            wb.write(fileOut);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public HSSFWorkbook getHSSFWorkbook(Object o, List<T> allProcessaccounts, HttpServletResponse response) throws NoSuchFieldException, IllegalAccessException {
        //滤空
        if (allProcessaccounts == null || allProcessaccounts.isEmpty()) {
            return null;
        }
        //反射获取属性
        Field[] fields = o.getClass().getDeclaredFields();
        //创建备用集合,用来存放需要展示的字段
        ArrayList<Field> fields1 = new ArrayList<>();
        for (Field field : fields) {
            //获取自定义注解对象
            Details annotation = o.getClass().getDeclaredField(field.getName()).getAnnotation(Details.class);
            //判断当前字段是否需要导出
            if (annotation.isExport()) {
                //新增进备用集合
                fields1.add(field);
            }
        }
        // 封装excel
        HSSFWorkbook hssfWorkbook = new HSSFWorkbook();
        //创建sheet页
        HSSFSheet sheet = hssfWorkbook.createSheet();
        Row row = sheet.createRow(0);
        if (row != null) {
            for (int i = 0; i < fields1.size(); i++) {
                //获取字段详情解释
                Details annotation = o.getClass().getDeclaredField(fields1.get(i).getName()).getAnnotation(Details.class);
                //添加标题并赋值
                row.createCell(i).setCellValue(annotation.value());
            }
        }
        //设置变量,便于后续方便给文本框更改样式
        int rowIndex = 0;
        //滤空
        if (allProcessaccounts != null && allProcessaccounts.size() > 0) {
            for (int i = 0; i < allProcessaccounts.size(); i++) {
                T p = allProcessaccounts.get(i);
                rowIndex++;
                //新增sheet页
                Row rowF = sheet.createRow(rowIndex);
                for (int j = 0; j < fields1.size(); j++) {
                    //获取反射过来的属性对象
                    Field field = fields1.get(j);
                    //把成员变量变为公有化
                    field.setAccessible(true);
                    //获取集合中成员变量的值
                    Object o1 = field.get(p);
                    //滤空赋值
                    if (o1 != null) {
                        rowF.createCell(j).setCellValue(o1.toString());
                    } else {
                        rowF.createCell(j).setCellValue("");
                    }
                }
            }
        }
        //设置样式
        for (int i = 0; i <= rowIndex; i++) {
            sheet.setColumnWidth(i, 20 * 256);
        }
        return hssfWorkbook;
    }
}