三. EasyExcel导入导出

一、概述

在日常java开发中，我们常用的excel处理工具为Apache POI或EasyExcel，EasyExcel相对于Apache POI就是简单易学，以下是工作总结的一些使用方法

二、EasyExcel导出

2.1 有模板导出

public class EasyExcelUtil {

    @Data
    @ColumnWidth(20) // 定义列宽
    public static class TestVO{
        @ExcelProperty( value = "姓名",index = 0)
        private String name;
        @ExcelProperty( value = "年龄",index = 1)
        private int age;
        @ExcelProperty( value = "学校",index = 2)
        private String school;
    }
     /**
     * 使用 模型 来写入Excel
     *
     * @param outputStream Excel的输出流
     * @param dataList         要写入的以 模型 为单位的数据
     * @param clazz        模型的类
     */
    public static void writeExcelWithModel(OutputStream outputStream, String sheetName, List dataList, Class clazz) {
       ExcelWriter excelWriter = EasyExcel.write(outputStream, clazz).autoTrim(true).autoCloseStream(true).excelType(ExcelTypeEnum.XLSX).build();
       WriteSheet writeSheet = EasyExcel.writerSheet(0, sheetName).build();
       excelWriter.write(dataList,writeSheet);
    }
    public static void main(String[] args) throws Exception {
        OutputStream outputStream = null;
        outputStream = new FileOutputStream(new File("E:\\6.xls"));
        List dataList = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
            TestVO testVO = new TestVO();
            testVO.setAge(i + 20);
            testVO.setName("vo" + i);
            testVO.setSchool("school" + i);
            dataList.add(testVO);
        }
        String sheetName = "导出文件";
        writeExcelWithModel(outputStream, sheetName, dataList, TestVO.class);
    }
}

2.2 无模板导出

2.2.1 泛型参数类

@Data
public class ExportExcelParam extends BaseDTO  {
    /**
     * 查询参数
     */
    private T queryParam;
    /**
     * 导出标题
     */
    private ArrayList titleList;
    /**
     * 导出文件名字
     */
    private String fileName;
}

2.2.2 导出接口

// 
public interface ExportExcel {
    /**
     * 查询
     *
     * @param param
     * @return
     */
    List> queryExportData(ExportExcelParam param);

    /**
     * 获取多语言列名
     *
     * @param param
     * @return
     */
    List getMultilingualHeader(ExportExcelParam param);

    /**
     * 开始导出
     * @param param
     * @param response
     */
    void exportStart(ExportExcelParam param, HttpServletResponse response)throws IOException;

//    @Override
//    public void exportStart(ExportExcelParam vendorAssesFormDto, HttpServletResponse response) throws IOException {
//        // 获取导出的数据
//        List> dataList = queryExportData(vendorAssesFormDto);
//        // 标题
//        List head = getMultilingualHeader(vendorAssesFormDto);
//        // 文件名
//        String fileName = vendorAssesFormDto.getFileName();
//        // 开始导出
//        EasyExcelUtil.exportStart(response, dataList, head, fileName);
//    }
}

2.2.3 工具类

public class EasyExcelUtil {
     /**
     * @param outputStream 输出流
     * @param sheetName 定义sheet名称
     * @param headList sheet表头
     * @param lineList sheet行数据
     */
    public static void writeExcel(OutputStream outputStream,String sheetName,List headList,List> lineList){
        List> list = new ArrayList<>();
        if(headList != null){
            headList.forEach(h -> list.add(Collections.singletonList(h)));
        }
        EasyExcel.write(outputStream).head(list).sheet(sheetName).doWrite(lineList);
    }
    /**
     * 获取输出流
     * @param response
     * @param fileName
     * @return
     * @throws IOException
     */
    public static ServletOutputStream getServletOutputStream(HttpServletResponse response, String fileName) throws IOException {
        fileName = URLEncoder.encode(fileName, "UTF-8");
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf8");
        response.setHeader("Content-Disposition", "attachment; filename=" + fileName + ".xlsx");
        response.setHeader("Pragma", "public");
        response.setHeader("Cache-Control", "no-store");
        response.addHeader("Cache-Control", "max-age=0");
        return response.getOutputStream();
    }
    /**
     * 开始导出
     * @param response
     * @param dataList
     * @param head
     * @param fileName
     * @throws IOException
     */
    public static void exportStart(HttpServletResponse response, List> dataList, List head, String fileName) throws IOException {
        // 获取输出流
        ServletOutputStream outputStream = EasyExcelUtil.getServletOutputStream(response, fileName);
        // 导出文件
        EasyExcelUtil. writeExcel(outputStream, fileName ,head,dataList);
    }
}

2.2.4 使用示例

pubile class EasyExcelTest implements ExportExcel< TestVO >{
    @Override
    public List> queryExportData(ExportExcelParam testVO) {
    // 编写业务
    //注意返回数据类型List>里面的Object最好为String类型，例如Date类型会出错
    }
    @Override
    public List getMultilingualHeader(ExportExcelParam testVO) {
    // 编写业务
    }
    @Override
    public void exportStart(ExportExcelParam testVO, HttpServletResponse response) throws IOException {
        // 获取导出的数据
        List> dataList = queryExportData(testVO);
        // 标题
        List head = getMultilingualHeader(testVO);
        // 文件名
        String fileName = vendorImproveFormDto.getFileName();
        // 开始导出
        EasyExcelUtil.exportStart(response, dataList, head, fileName);
    }
}

三、EasyExcel导入

3.1有模型导入

public class EasyExcelUtil {
    @Data
    public static class TestVO{
        @ExcelProperty( value = "姓名",index = 0)
        private String name;
        @ExcelProperty( value = "年龄",index = 1)
        private int age;
        @ExcelProperty( value = "学校",index = 2)
        private String school;
    }
    /**
     * 使用 模型 来读取Excel
     * @param fileInputStream Excel的输入流
     * @param clazz 模型的类
     * @return 返回 模型 的列表(为object列表,需强转)
     */
    public static List