<!--EasyExcel相關(guān)依賴(lài)-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>easyexcel</artifactId>
    <version>3.0.5</version>
</dependency>

@Data
@NoArgsConstructor
@AllArgsConstructor
@TableName("stu_info")
@ApiModel("學(xué)生信息")
//@ExcelIgnoreUnannotated 沒(méi)有注解的字段都不轉(zhuǎn)換
public class StuInfo {

    private static final long serialVersionUID = 1L;
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    /**
     * 姓名
     */
    // 設(shè)置字體，此處代表使用斜體
//    @ContentFontStyle(italic = BooleanEnum.TRUE)
    // 設(shè)置列寬度的注解,注解中只有一個(gè)參數(shù)value，value的單位是字符長(zhǎng)度，最大可以設(shè)置255個(gè)字符
    @ColumnWidth(10)
    // @ExcelProperty 注解中有三個(gè)參數(shù)value,index,converter分別代表表名，列序號(hào)，數(shù)據(jù)轉(zhuǎn)換方式
    @ApiModelProperty("姓名")
    @ExcelProperty(value = "姓名",order = 0)
    @ExportHeader(value = "姓名",index = 1)
    private String name;
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    /**
     * 年齡
     */
//    @ExcelIgnore不將該字段轉(zhuǎn)換成Excel
    @ExcelProperty(value = "年齡",order = 1)
    @ApiModelProperty("年齡")
    @ExportHeader(value = "年齡",index = 2)
    private Integer age;
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    /**
     * 身高
     */
    //自定義格式-位數(shù)
//    @NumberFormat("#.##%")
    @ExcelProperty(value = "身高",order = 2)
    @ApiModelProperty("身高")
    @ExportHeader(value = "身高",index = 4)
    private Double tall;
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    /**
     * 自我介紹
     */
    @ExcelProperty(value = "自我介紹",order = 3)
    @ApiModelProperty("自我介紹")
    @ExportHeader(value = "自我介紹",index = 3,ignore = true)
    private String selfIntroduce;
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    /**
     * 圖片信息
     */
    @ExcelProperty(value = "圖片信息",order = 4)
    @ApiModelProperty("圖片信息")
    @ExportHeader(value = "圖片信息",ignore = true)
    private Blob picture;
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    /**
     * 性別
     */
    @ExcelProperty(value = "性別",order = 5)
    @ApiModelProperty("性別")
    private Integer gender;
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    /**
     * 入學(xué)時(shí)間
     */
    //自定義格式-時(shí)間格式
    @DateTimeFormat("yyyy-MM-dd HH:mm:ss:")
    @ExcelProperty(value = "入學(xué)時(shí)間",order = 6)
    @ApiModelProperty("入學(xué)時(shí)間")
    private String intake;
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    /**
     * 出生日期
     */
    @ExcelProperty(value = "出生日期",order = 7)
    @ApiModelProperty("出生日期")
    private String birthday;
}

@Slf4j
public class UploadDataListener<T> implements ReadListener<T> {
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    /**
     * 每隔5條存儲(chǔ)數(shù)據(jù)庫(kù)，實(shí)際使用中可以100條，然后清理list ，方便內(nèi)存回收
     */
    private static final int BATCH_COUNT = 100;
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    /**
     * 緩存的數(shù)據(jù)
     */
    private List<T> cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
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    /**
     * Predicate用于過(guò)濾數(shù)據(jù)
     */
    private Predicate<T> predicate;
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    /**
     * 調(diào)用持久層批量保存
     */
    private Consumer<Collection<T>> consumer;
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    public UploadDataListener(Predicate<T> predicate, Consumer<Collection<T>> consumer) {
        this.predicate = predicate;
        this.consumer = consumer;
    }
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    public UploadDataListener(Consumer<Collection<T>> consumer) {
        this.consumer = consumer;
    }
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    /**
     * 如果使用了spring,請(qǐng)使用這個(gè)構(gòu)造方法。每次創(chuàng)建Listener的時(shí)候需要把spring管理的類(lèi)傳進(jìn)來(lái)
     *
     * @param demoDAO
     */
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    /**
     * 這個(gè)每一條數(shù)據(jù)解析都會(huì)來(lái)調(diào)用
     *
     * @param data    one row value. Is is same as {@link AnalysisContext#readRowHolder()}
     * @param context
     */
    @Override
    public void invoke(T data, AnalysisContext context) {
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        if (predicate != null && !predicate.test(data)) {
            return;
        }
        cachedDataList.add(data);
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        // 達(dá)到BATCH_COUNT了，需要去存儲(chǔ)一次數(shù)據(jù)庫(kù)，防止數(shù)據(jù)幾萬(wàn)條數(shù)據(jù)在內(nèi)存，容易OOM
        if (cachedDataList.size() >= BATCH_COUNT) {
            try {
                // 執(zhí)行具體消費(fèi)邏輯
                consumer.accept(cachedDataList);
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            } catch (Exception e) {
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                log.error("Failed to upload data!data={}", cachedDataList);
                throw new BizException("導(dǎo)入失敗");
            }
            // 存儲(chǔ)完成清理 list
            cachedDataList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
        }
    }
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    /**
     * 所有數(shù)據(jù)解析完成了 都會(huì)來(lái)調(diào)用
     *
     * @param context
     */
    @Override
    public void doAfterAllAnalysed(AnalysisContext context) {
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        // 這里也要保存數(shù)據(jù)，確保最后遺留的數(shù)據(jù)也存儲(chǔ)到數(shù)據(jù)庫(kù)
        if (CollUtil.isNotEmpty(cachedDataList)) {
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            try {
                // 執(zhí)行具體消費(fèi)邏輯
                consumer.accept(cachedDataList);
                log.info("所有數(shù)據(jù)解析完成！");
            } catch (Exception e) {
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                log.error("Failed to upload data!data={}", cachedDataList);
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                // 拋出自定義的提示信息
                if (e instanceof BizException) {
                    throw e;
                }
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                throw new BizException("導(dǎo)入失敗");
            }
        }
    }
}

@ApiOperation("只需要一個(gè)readListener，解決全部的問(wèn)題")
    @PostMapping("/update")
    @ResponseBody
    public R<String> aListener4AllExcel(MultipartFile file) throws IOException {
        try {
            EasyExcel.read(file.getInputStream(),
                            StuInfo.class,
                            new UploadDataListener<StuInfo>(
                                    list -> {
                                        // 校驗(yàn)數(shù)據(jù)
//                                        ValidationUtils.validate(list);
                                        // dao 保存···
                                        //最好是手寫(xiě)一個(gè)，不要使用mybatis-plus的一條條新增的邏輯
                                        service.saveBatch(list);
                                        log.info("從Excel導(dǎo)入數(shù)據(jù)一共 {} 行 ", list.size());
                                    }))
                    .sheet()
                    .doRead();
        } catch (IOException e) {
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            log.error("導(dǎo)入失敗", e);
            throw new BizException("導(dǎo)入失敗");
        }
        return R.success("SUCCESS");
    }

@ApiOperation("只需要一個(gè)readListener，解決全部的問(wèn)題")
    @PostMapping("/listenMapDara")
    @ResponseBody
    public R<String> listenMapDara(@ApiParam(value = "表編碼", required = true)
                                   @NotBlank(message = "表編碼不能為空")
                                   @RequestParam("tableCode") String tableCode,
                                   @ApiParam(value = "上傳的文件", required = true)
                                   @NotNull(message = "上傳文件不能為空") MultipartFile file) throws IOException {
        try {
            //根據(jù)tableCode獲取這張表的字段，可以作為insert與劇中的信息
            EasyExcel.read(file.getInputStream(),
                            new NonClazzOrientedListener(
                                    list -> {
                                        // 校驗(yàn)數(shù)據(jù)
//                                        ValidationUtils.validate(list);
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                                        // dao 保存···
                                        log.info("從Excel導(dǎo)入數(shù)據(jù)一共 {} 行 ", list.size());
                                    }))
                    .sheet()
                    .doRead();
        } catch (IOException e) {
            log.error("導(dǎo)入失敗", e);
            throw new BizException("導(dǎo)入失敗");
        }
        return R.success("SUCCESS");
    }

@Slf4j
public class NonClazzOrientedListener implements ReadListener<Map<Integer, String>> {
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    /**
     * 每隔5條存儲(chǔ)數(shù)據(jù)庫(kù)，實(shí)際使用中可以100條，然后清理list ，方便內(nèi)存回收
     */
    private static final int BATCH_COUNT = 100;
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    private List<List<Object>> rowsList = ListUtils.newArrayListWithExpectedSize(BATCH_COUNT);
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    private List<Object> rowList = new ArrayList<>();
    /**
     * Predicate用于過(guò)濾數(shù)據(jù)
     */
    private Predicate<Map<Integer, String>> predicate;
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    /**
     * 調(diào)用持久層批量保存
     */
    private Consumer<List> consumer;
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    public NonClazzOrientedListener(Predicate<Map<Integer, String>> predicate, Consumer<List> consumer) {
        this.predicate = predicate;
        this.consumer = consumer;
    }
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    public NonClazzOrientedListener(Consumer<List> consumer) {
        this.consumer = consumer;
    }
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    /**
     * 添加deviceName標(biāo)識(shí)
     */
    private boolean flag = false;
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    @Override
    public void invoke(Map<Integer, String> row, AnalysisContext analysisContext) {
        consumer.accept(rowsList);
        rowList.clear();
        row.forEach((k, v) -> {
            log.debug("key is {},value is {}", k, v);
            rowList.add(v == null ? "" : v);
        });
        rowsList.add(rowList);
        if (rowsList.size() > BATCH_COUNT) {
            log.debug("執(zhí)行存儲(chǔ)程序");
            log.info("rowsList is {}", rowsList);
            rowsList.clear();
        }
    }
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    @Override
    public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        consumer.accept(rowsList);
        if (CollUtil.isNotEmpty(rowsList)) {
            try {
                log.debug("執(zhí)行最后的程序");
                log.info("rowsList is {}", rowsList);
            } catch (Exception e) {
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                log.error("Failed to upload data!data={}", rowsList);
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                // 拋出自定義的提示信息
                if (e instanceof BizException) {
                    throw e;
                }
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                throw new BizException("導(dǎo)入失敗");
            } finally {
                rowsList.clear();
            }
        }
    }

 /**
     * 這里會(huì)一行行的返回頭
     *
     * @param headMap
     * @param context
     */
    @Override
    public void invokeHead(Map<Integer, ReadCellData<?>> headMap, AnalysisContext context) {
        //該方法必然會(huì)在讀取數(shù)據(jù)之前進(jìn)行
        Map<Integer, String> columMap = ConverterUtils.convertToStringMap(headMap, context);
        //通過(guò)數(shù)據(jù)交互拿到這個(gè)表的表頭
//        Map<String,String> columnList=dao.xxxx();
        Map<String, String> columnList = new HashMap();
        columMap.forEach((key, value) -> {
            if (columnList.containsKey(value)) {
                filterList.add(key);
            }
        });
        //過(guò)濾到了只存在表里面的數(shù)據(jù)，順序就不用擔(dān)心了，可以直接把filterList的數(shù)據(jù)用于排序，可以根據(jù)mybatis做一個(gè)動(dòng)態(tài)sql進(jìn)行應(yīng)用
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        log.info("解析到一條頭數(shù)據(jù):{}", JSON.toJSONString(columMap));
        // 如果想轉(zhuǎn)成成 Map<Integer,String>
        // 方案1： 不要implements ReadListener 而是 extends AnalysisEventListener
        // 方案2： 調(diào)用 ConverterUtils.convertToStringMap(headMap, context) 自動(dòng)會(huì)轉(zhuǎn)換
    }

    public <T> void commonExport(String fileName, List<T> data, Class<T> clazz, HttpServletResponse response) throws IOException {
        if (CollectionUtil.isEmpty(data)) {
            data = new ArrayList<>();
        }
        //設(shè)置標(biāo)題
        fileName = URLEncoder.encode(fileName, "UTF-8");
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream()).head(clazz).sheet("sheet1").doWrite(data);
    }

public void exportFreely(String fileName, List<List<Object>> data, List<List<String>> head, HttpServletResponse response) throws IOException {
        if (CollectionUtil.isEmpty(data)) {
            data = new ArrayList<>();
        }
        //設(shè)置標(biāo)題
        fileName = URLEncoder.encode(fileName, "UTF-8");
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        response.setHeader("Content-disposition", "attachment;filename=" + fileName + ".xlsx");
        EasyExcel.write(response.getOutputStream()).head(head).sheet("sheet1").doWrite(data);
    }