好用的 easyExcel 工具类

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.ExcelWriter;
import com.alibaba.excel.context.AnalysisContext;
import com.alibaba.excel.event.AnalysisEventListener;
import com.alibaba.excel.metadata.Head;
import com.alibaba.excel.read.metadata.ReadSheet;
import com.alibaba.excel.write.handler.WriteHandler;
import com.alibaba.excel.write.merge.AbstractMergeStrategy;
import com.alibaba.excel.write.metadata.WriteSheet;
import com.alibaba.excel.write.metadata.fill.FillConfig;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.ibatis.session.ResultHandler;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.RegionUtil;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.*;
import java.util.function.BiConsumer;


@Slf4j
public class ExcelUtils {

    private static final String FILE_SUFFIX = ".xlsx";

    /**
     * 导出excel
     * @param response
     * @param fileName  文件名
     * @param sheetName sheet名
     * @param list      数据 list为空返回 空Excel
     */
    public static void export(HttpServletResponse response, String fileName, String sheetName, List<?> list, Class<?> zlass) throws Exception {
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        String fileNameCode = URLEncoder.encode(fileName, "utf-8").replaceAll("\+", "%20");
        response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileNameCode + FILE_SUFFIX);
        EasyExcel.write(response.getOutputStream(), zlass)
                .sheet(sheetName).doWrite(list);
    }

    /**
     * excel导出 批注
     * @param response
     * @param fileName 文件名
     * @param list 导出数据
     * @param writeHandler 批注拦截器
     */
    public static void export(HttpServletResponse response, String fileName,
                              List list, WriteHandler writeHandler, Class zlass) throws Exception {
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        String fileNameCode = URLEncoder.encode(fileName, StandardCharsets.UTF_8);
        response.setHeader("Content-disposition", "attachment;filename=" + fileNameCode + FILE_SUFFIX);
        EasyExcel.write(response.getOutputStream(), zlass)
                .inMemory(Boolean.TRUE).registerWriteHandler(writeHandler)
                .sheet(fileName).doWrite(list);
    }

    public static void fill(ExcelWriter excelWriter, FillConfig fillConfig, Object data, String sheetName){
        WriteSheet writeSheet= EasyExcel.writerSheet().build();
        if (sheetName != null) {
            writeSheet.setSheetName(sheetName);
        }
        excelWriter.fill(data, fillConfig, writeSheet);
    }

    /**
     * 目前仅支持mybatis的流处理
     * @param query 查询条件的bean
     * @param consumer DAO对应的方法
     * @param excelWriter 由于分层的原因这个需要手动构造来传
     *                    参考构造
     *                    ExcelWriter excelWriter = EasyExcel.write(os, OrderDownloadDTO.class).build();
     * @param <T>
     * @param <S>
     */
    public static <T,S> void bigDataExport(T query, BiConsumer<T, ResultHandler<S>> consumer,
                                           ExcelWriter excelWriter) {
        try {
            WriteSheet[] writeSheet = new WriteSheet[] {
                    EasyExcel.writerSheet(0, "sheet").build()
            };
            List<S> list = new ArrayList<>(1000);
            // 0 代表当前的条数，等于100万时会被置为0
            // 1 代表已经有多少个一百万
            int [] c = new int[2];
            consumer.accept(query, data -> {
                c[0]++;
                list.add(data.getResultObject());
                if ((c[0] % 1000) == 0) {
                    excelWriter.write(list, writeSheet[0]);
                    list.clear();
                    if (c[0] == 1000000) {
                        c[1]++;
                        writeSheet[0] = EasyExcel.writerSheet(c[1], "sheet" + c[1]).build();
                        c[0] = 0;
                    }
                }
            });
            //可能有剩余的数据
            excelWriter.write(list, writeSheet[0]);
        } finally {
            excelWriter.finish();
        }
    }

    /**
     * 导出Excel
     * @param response
     * @param fileName 文件名
     * @param list 导出数据
     * @return void
     */
    public static void export(HttpServletResponse response, String fileName, List<?> list, Class<?> zlass) throws Exception {
        export(response, fileName, fileName, list, zlass);
    }

    /**
     * 读取excel文件
     * @param file 文件
     * @param clazz 模板类
     * @return java.util.List
     */
    public  static <T> List<T> read(MultipartFile file, Class<T> clazz) {
        try {
            return EasyExcel.read(new BufferedInputStream(file.getInputStream())).head(clazz).sheet()
                    .doReadSync();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * Excel多sheet导出
     * @param data must not null
     * @param sheetNames enable is null
     * @param outputStream
     */
    public static void writeExcel(List<List> data, List<String> sheetNames, OutputStream outputStream) {
        if(data == null) {
            throw new RuntimeException("数据不存在");
        }
        if(sheetNames != null && data.size() != sheetNames.size()) {
            throw new RuntimeException("sheet数据数量和sheet名称数量不相等");
        }
        ExcelWriter excelWriter = EasyExcel.write(outputStream).build();
        for(int i = 0;i < data.size();i++) {
            List d = data.get(i);
            if(d != null && d.size() > 0) {
                WriteSheet ws = EasyExcel.writerSheet().sheetNo(i)
                        .sheetName(sheetNames == null ? "sheet" + i : sheetNames.get(i))
                        .head(d.get(0).getClass()).build();
                excelWriter.write(d, ws);
            }
        }
        excelWriter.finish();
    }

    public static List<LinkedHashMap<Integer, Object>> readExcel(InputStream inputStream) {
        return EasyExcel.read(inputStream).headRowNumber(0).autoCloseStream(true).doReadAllSync();
    }

    public static List<LinkedHashMap<Integer, Object>> readExcel(InputStream inputStream, String sheetName) {
        return EasyExcel.read(inputStream).headRowNumber(0).autoCloseStream(true).sheet(sheetName).doReadSync();
    }

    public static List<LinkedHashMap<Integer, Object>> readExcel(InputStream inputStream, Integer sheetIndex) {
        return EasyExcel.read(inputStream).headRowNumber(0).autoCloseStream(true).sheet(sheetIndex).doReadSync();
    }

    public static Map<String, List<LinkedHashMap<Integer, Object>>> readNameExcel(InputStream inputStream, List<ReadSheet> readSheets) {
        SyncManySheetNameReadListener syncReadListener = new SyncManySheetNameReadListener();
        EasyExcel.read(inputStream).headRowNumber(0).registerReadListener(syncReadListener).autoCloseStream(true)
                .build().read(readSheets).finish();
        return syncReadListener.getMap();
    }

    public static Map<String, List<LinkedHashMap<Integer, Object>>> readNameExcel(InputStream inputStream) {
        SyncManySheetNameReadListener syncReadListener = new SyncManySheetNameReadListener();
        EasyExcel.read(inputStream).headRowNumber(0).registerReadListener(syncReadListener).autoCloseStream(true)
                .doReadAll();
        return syncReadListener.getMap();
    }

    public static Map<Integer, List<LinkedHashMap<Integer, Object>>> readIndexExcel(InputStream inputStream, List<ReadSheet> readSheets) {
        SyncManySheetIndexReadListener syncReadListener = new SyncManySheetIndexReadListener();
        EasyExcel.read(inputStream).headRowNumber(0).registerReadListener(syncReadListener).autoCloseStream(true)
                .build().read(readSheets).finish();
        return syncReadListener.getMap();
    }

    public static Map<String, List<LinkedHashMap<Integer, Object>>> readExcel(List<String> sheetNames, InputStream is) {
        Map<String, List<LinkedHashMap<Integer, Object>>> data;
        if(DataUtils.isEmpty(sheetNames)) {
            data = new HashMap<>();
            data.put("", readExcel(is));
        } else {
            List<ReadSheet> list = new ArrayList<>();
            for(String name : sheetNames) {
                list.add(new ReadSheet(null, name));
            }
            data = readNameExcel(is, list);
        }
        return data;
    }

    public static String getAsString(LinkedHashMap<Integer, Object> cell, int i) {
        Object o = cell.get(i);
        if(o == null) {
            return null;
        }
        return o.toString();
    }

    public static String getAsStringEmptyToNull(LinkedHashMap<Integer, Object> cell, int i) {
        String t = getAsString(cell, i);
        if(StringUtils.isBlank(t)) {
            return null;
        }
        return t;
    }

    private static class SyncManySheetNameReadListener extends AnalysisEventListener<Object> {
        private Map<String, List<LinkedHashMap<Integer, Object>>> map = new HashMap<>();

        public SyncManySheetNameReadListener() { }

        @Override
        public void invoke(Object object, AnalysisContext context) {
            map.computeIfAbsent(context.readSheetHolder().getSheetName(),
                    a -> new ArrayList<>()).add((LinkedHashMap<Integer, Object>) object);
        }

        @Override
        public void doAfterAllAnalysed(AnalysisContext context) { }

        public Map<String, List<LinkedHashMap<Integer, Object>>> getMap() {
            return this.map;
        }

    }


    private static class SyncManySheetIndexReadListener extends AnalysisEventListener<Object> {
        private Map<Integer, List<LinkedHashMap<Integer, Object>>> map = new HashMap<>();

        public SyncManySheetIndexReadListener() { }

        @Override
        public void invoke(Object object, AnalysisContext context) {
            map.computeIfAbsent(context.readSheetHolder().getSheetNo(),
                    a -> new ArrayList<>()).add((LinkedHashMap<Integer, Object>) object);
        }

        @Override
        public void doAfterAllAnalysed(AnalysisContext context) { }

        public Map<Integer, List<LinkedHashMap<Integer, Object>>> getMap() {
            return this.map;
        }

    }

    public static class MergeCell extends AbstractMergeStrategy {

        @Override
        protected void merge(Sheet sheet, Cell cell, Head head, Integer relativeRowIndex) {
            if(relativeRowIndex == null || relativeRowIndex == 0) {
                return;
            }
            int rowIndex = cell.getRowIndex();
            int colIndex = cell.getColumnIndex();
            sheet = cell.getSheet();
            Row preRow = sheet.getRow(rowIndex - 1);
            Cell preCell = preRow.getCell(colIndex);
            List<CellRangeAddress> list = sheet.getMergedRegions();
            for(int i = 0;i < list.size();i++) {
                CellRangeAddress cellRangeAddress = list.get(i);
                if(cellRangeAddress.containsRow(preCell.getRowIndex()) &&
                    cellRangeAddress.containsColumn(preCell.getColumnIndex())) {
                    int lastColIndex = cellRangeAddress.getLastColumn();
                    int firstColIndex = cellRangeAddress.getFirstColumn();
                    CellRangeAddress cra = new CellRangeAddress(cell.getRowIndex(), cell.getRowIndex(),
                            firstColIndex, lastColIndex);
                    sheet.addMergedRegion(cra);
                    RegionUtil.setBorderBottom(BorderStyle.THIN, cra, sheet);
                    RegionUtil.setBorderLeft(BorderStyle.THIN, cra, sheet);
                    RegionUtil.setBorderRight(BorderStyle.THIN, cra, sheet);
                    RegionUtil.setBorderTop(BorderStyle.THIN, cra, sheet);
                }
            }
        }
    }
}

模版导出 excel 使用例子

    @Test
    public void test7() throws Exception {
        InputStream is = FileUtil.getInJarFileStream("invoice.xls");
        ExcelWriter writer = EasyExcel.write("/Users/abc/Desktop/test.xls")
                .registerWriteHandler(new ExcelUtils.MergeCell())
                .withTemplate(is).build();
        InvoiceInfoDTO dto = FillBeanUtil.randomFillBean(InvoiceInfoDTO.class);
        ExcelUtils.fill(writer, null, dto, "invoice");
        dto.getDetails().add(FillBeanUtil.randomFillBean(InvoiceDetailEntity.class));
        FillConfig config =
                FillConfig.builder().forceNewRow(true).build();
        ExcelUtils.fill(writer, config, dto.getDetails(), "invoice");
        writer.finish();
    }