springboot导出（POI）

POI官方文档

引入依赖

        
        
            org.apache.poi
            poi
            4.1.2
        
        
            org.apache.poi
            poi-ooxml
            4.1.2
        
        
            org.apache.poi
            poi-ooxml-schemas
            4.1.2
        

定义注解

        我们结合自定义注解，让导出使用起来更方便简洁且更容易扩展。

@ExcelField

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelField {

    /**
     * 字段名
     */
    String name() default "";

    /**
     * 字段顺序
     */
    int order() default 1;

    /**
     * 单元格宽度
     */
    int width() default 100;

    /**
     * 日期格式
     */
    String dateFormat() default "yyyy-MM-dd HH:mm:ss";
}

@ExcelHeader 

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
public @interface ExcelHeader {

    /**
     * 文件名称
     * @return
     */
    String fileName() default "导出文件";

    /**
     * sheet页名称
     * @return
     */
    String sheetName() default "sheet1";

    /**
     * 表头是否加粗
     * @return
     */
    boolean headBold() default false;

    /**
     * 表头颜色
     * @return
     */
    IndexedColors headColor() default IndexedColors.GREEN;
}

编写POI导出工具类

public class ExcelExportUtil {

    /*
     * @description: 导出 

     * @create: 2023/9/12 16:28 

     * @param response
     * @param data
     * @param clazz
     * @return void
     */
    public static void export(HttpServletResponse response, List data, Class clazz){
        if(ObjectUtils.isEmpty(response) || ObjectUtils.isEmpty(data)){
            return;
        }
        //解析表头
        ExcelHeader excelHeader = getExcelHeader(clazz);
        if(ObjectUtils.isEmpty(excelHeader)){
            return;
        }
        //解析字段
        List keyList = new ArrayList<>();
        List excelFieldList = new ArrayList<>();
        getExcelFields(clazz, keyList, excelFieldList);
        if(ObjectUtils.isEmpty(keyList)){
            return;
        }
        //创建workbook，SXSSFWorkbook支持大数据量导出
        Workbook workbook = new SXSSFWorkbook();
        //创建sheet
        Sheet sheet = workbook.createSheet(excelHeader.sheetName());
        //创建表头
        Row row = createHeader(workbook, sheet, excelHeader, excelFieldList);
        //写入数据
        setData(data, sheet, keyList, excelFieldList);
        //输出文件
        try {
            String fileName = URLEncoder.encode(excelHeader.fileName(), "UTF-8");
            response.setContentType("application/octet-stream");
            response.setHeader("content-disposition", "attachment;filename=" + new String(fileName.getBytes("ISO8859-1")));
            response.setHeader("filename", fileName);
            workbook.write(response.getOutputStream());
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                workbook.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /*
     * @description: 设置数据 

     * @create: 2023/9/13 9:33 

     * @param data
     * @param sheet
     * @param keyList
     * @return void
     */
    private static void setData(List data, Sheet sheet, List keyList, List excelFieldList){
        List> dataList = convertDataToJson(data);
        Map rowData;
        String dataKey;
        Object value;
        ExcelField excelField;
        for (int i = 0; i < dataList.size(); i++) {
            Row row = sheet.createRow(i+1);
            rowData = dataList.get(i);
            for (int j = 0; j < keyList.size(); j++) {
                dataKey = keyList.get(j);
                value = rowData.get(dataKey);
                if(ObjectUtils.isEmpty(value)){
                    continue;
                }
                Cell cell = row.createCell(j);
                cell.setCellValue(value.toString());
            }
        }
    }

    /*
     * @description: 创建表头 

     * @create: 2023/9/12 17:28 

     * @param workbook
     * @param sheet
     * @param excelFieldList
     * @return org.apache.poi.ss.usermodel.Row
     */
    private static Row createHeader(Workbook workbook, Sheet sheet, ExcelHeader excelHeader,List excelFieldList){
        //创建行
        Row row = sheet.createRow(0);
        //创建行样式
        CellStyle cellStyle = workbook.createCellStyle();
        //单元格颜色
        cellStyle.setFillForegroundColor(excelHeader.headColor().getIndex());
        cellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        //水平居中
        cellStyle.setAlignment(HorizontalAlignment.CENTER);
        //字体
        Font font =  workbook.createFont();
        font.setBold(excelHeader.headBold());
        font.setFontName("宋体");
        cellStyle.setFont(font);
        for (int i = 0; i < excelFieldList.size(); i++) {
            ExcelField excelField = excelFieldList.get(i);
            Cell cell = row.createCell(i);
            cell.setCellValue(excelField.name());
            cell.setCellStyle(cellStyle);
            sheet.setColumnWidth(i+1, excelField.width() * 10 );
        }
        return row;
    }

    /*
     * @description: 获取excel头注解信息 

     * @create: 2023/9/12 10:28 

     * @param clazz
     * @return com.springboot.demo.base.annotation.ExcelHeader
     */
    private static ExcelHeader getExcelHeader(Class clazz){
        ExcelHeader excelHeader = clazz.getAnnotation(ExcelHeader.class);
        return excelHeader;
    }

    /*
     * @description: 获取excel字段注解信息 

     * @create: 2023/9/12 10:31 

     * @param clazz
     * @return java.util.List
     */
    private static void getExcelFields(Class clazz, List keyList, List excelFieldList){
        Field[] fields = clazz.getDeclaredFields();
        if(ObjectUtils.isEmpty(fields)){
            return;
        }
        Map keyMap = new HashMap<>();
        for(Field field : fields){
            ExcelField excelField = field.getAnnotation(ExcelField.class);
            if(ObjectUtils.isNotEmpty(excelField)){
                keyMap.put(excelField.name(), field.getName());
                excelFieldList.add(excelField);
            }
        }
        if(ObjectUtils.isNotEmpty(excelFieldList)){
            excelFieldList = excelFieldList.stream().sorted(Comparator.comparing(ExcelField::order)).collect(
                Collectors.toList());
        }
        for (ExcelField excelField : excelFieldList) {
            keyList.add(keyMap.get(excelField.name()));
        }
    }

    /*
     * @description: 将数据转未json 

     * @create: 2023/9/13 10:00 

     * @param data
     * @return java.util.List>
     */
    private static List> convertDataToJson(List data){
        ObjectMapper objectMapper = new ObjectMapper();
        //日期格式
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        //设置时区
        objectMapper.setTimeZone(TimeZone.getTimeZone("Asia/Shanghai"));
        //序列化-忽略null值的属性
        objectMapper.setSerializationInclusion(Include.NON_NULL);
        //序列化-允许序列化空对象
        objectMapper.disable(SerializationFeature.FAIL_ON_EMPTY_BEANS);
        List> dataList = objectMapper.convertValue(data, List.class);
        return dataList;
    }
}

测试

Test.java

@Data
@ExcelHeader(fileName = "导出文件.xlsx")
public class Test {

    @ExcelField(name = "字段1", width = 500, order = 1)
    private String field1 = "撒大声地撒分都是";

    @ExcelField(name = "字段2", width = 400, order = 2)
    private Integer field2 = 11;

    @ExcelField(name = "字段3", width = 300, order = 5)
    private Double field3;

    @ExcelField(name = "字段4", width = 700, order = 10)
    private BigDecimal field4 = new BigDecimal("12312312312.222");

    @ExcelField(name = "字段5", width = 600, order = 3)
    private Date field5 = new Date();
}

TestController.java

@Api(tags = "测试")
@RestController
@RequestMapping("/test")
public class TestController {

    @ApiOperation("test")
    @PostMapping("/test")
    public void test(HttpServletResponse response){
        Test test = new Test();
        List list = new ArrayList<>();
        for (int i = 0; i < 10000; i++) {
            list.add(test);
        }
        ExcelExportUtil.export(response, list, Test.class);
    }
}

输出结果