Java Spring使用poi导出Excel

安装各种Excel依赖包

<!--        Excel-->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>3.17</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>3.17</version>
        </dependency>
<!--        other tool-->
        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.9</version>
        </dependency>
        <dependency>
            <groupId>commons-collections</groupId>
            <artifactId>commons-collections</artifactId>
            <version>3.2.2</version>
        </dependency>

编写一个Excel工具类。

package com.x.x.util;

import java.awt.image.BufferedImage;
import java.io.*;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import javax.imageio.ImageIO;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.collections.CollectionUtils;
import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.CharUtils;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.lang3.math.NumberUtils;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.http.MediaType;
import org.springframework.web.multipart.MultipartFile;

import com.cross1000.wx_qjh.model.ExcelColumn;

public class ExcelUtils {

    private final static Logger log = LoggerFactory.getLogger(ExcelUtils.class);

    private final static String EXCEL2003 = "xls";
    private final static String EXCEL2007 = "xlsx";

    public static <T> List<T> readExcel(String path, Class<T> cls, MultipartFile file) {

        String fileName = file.getOriginalFilename();
        if (!fileName.matches("^.+\\.(?i)(xls)$") && !fileName.matches("^.+\\.(?i)(xlsx)$")) {
            log.error("上传文件格式不正确");
        }
        List<T> dataList = new ArrayList<>();
        Workbook workbook = null;
        try {
            InputStream is = file.getInputStream();
            if (fileName.endsWith(EXCEL2007)) {
//                FileInputStream is = new FileInputStream(new File(path));
                workbook = new XSSFWorkbook(is);
            }
            if (fileName.endsWith(EXCEL2003)) {
//                FileInputStream is = new FileInputStream(new File(path));
                workbook = new HSSFWorkbook(is);
            }
            if (workbook != null) {
                //类映射  注解 value-->bean columns
                Map<String, List<Field>> classMap = new HashMap<>();
                List<Field> fields = Stream.of(cls.getDeclaredFields()).collect(Collectors.toList());
                fields.forEach(
                        field -> {
                            ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                            if (annotation != null) {
                                String value = annotation.value();
                                if (StringUtils.isBlank(value)) {
                                    return;//return起到的作用和continue是相同的 语法
                                }
                                if (!classMap.containsKey(value)) {
                                    classMap.put(value, new ArrayList<>());
                                }
                                field.setAccessible(true);
                                classMap.get(value).add(field);
                            }
                        }
                );
                //索引-->columns
                Map<Integer, List<Field>> reflectionMap = new HashMap<>(16);
                //默认读取第一个sheet
                Sheet sheet = workbook.getSheetAt(0);

                boolean firstRow = true;
                for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
                    Row row = sheet.getRow(i);
                    //首行  提取注解
                    if (firstRow) {
                        for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
                            Cell cell = row.getCell(j);
                            String cellValue = getCellValue(cell);
                            if (classMap.containsKey(cellValue)) {
                                reflectionMap.put(j, classMap.get(cellValue));
                            }
                        }
                        firstRow = false;
                    } else {
                        //忽略空白行
                        if (row == null) {
                            continue;
                        }
                        try {
                            T t = cls.newInstance();
                            //判断是否为空白行
                            boolean allBlank = true;
                            for (int j = row.getFirstCellNum(); j <= row.getLastCellNum(); j++) {
                                if (reflectionMap.containsKey(j)) {
                                    Cell cell = row.getCell(j);
                                    String cellValue = getCellValue(cell);
                                    if (StringUtils.isNotBlank(cellValue)) {
                                        allBlank = false;
                                    }
                                    List<Field> fieldList = reflectionMap.get(j);
                                    fieldList.forEach(
                                            x -> {
                                                try {
                                                    handleField(t, cellValue, x);
                                                } catch (Exception e) {
                                                    log.error(String.format("reflect field:%s value:%s exception!", x.getName(), cellValue), e);
                                                }
                                            }
                                    );
                                }
                            }
                            if (!allBlank) {
                                dataList.add(t);
                            } else {
                                log.warn(String.format("row:%s is blank ignore!", i));
                            }
                        } catch (Exception e) {
                            log.error(String.format("parse row:%s exception!", i), e);
                        }
                    }
                }
            }
        } catch (Exception e) {
            log.error(String.format("parse excel exception!"), e);
        } finally {
            if (workbook != null) {
                try {
                    workbook.close();
                } catch (Exception e) {
                    log.error(String.format("parse excel exception!"), e);
                }
            }
        }
        return dataList;
    }

    private static <T> void handleField(T t, String value, Field field) throws Exception {
        Class<?> type = field.getType();
        if (type == null || type == void.class || StringUtils.isBlank(value)) {
            return;
        }
        if (type == Object.class) {
            field.set(t, value);
            //数字类型
        } else if (type.getSuperclass() == null || type.getSuperclass() == Number.class) {
            if (type == int.class || type == Integer.class) {
                field.set(t, NumberUtils.toInt(value));
            } else if (type == long.class || type == Long.class) {
                field.set(t, NumberUtils.toLong(value));
            } else if (type == byte.class || type == Byte.class) {
                field.set(t, NumberUtils.toByte(value));
            } else if (type == short.class || type == Short.class) {
                field.set(t, NumberUtils.toShort(value));
            } else if (type == double.class || type == Double.class) {
                field.set(t, NumberUtils.toDouble(value));
            } else if (type == float.class || type == Float.class) {
                field.set(t, NumberUtils.toFloat(value));
            } else if (type == char.class || type == Character.class) {
                field.set(t, CharUtils.toChar(value));
            } else if (type == boolean.class) {
                field.set(t, BooleanUtils.toBoolean(value));
            } else if (type == BigDecimal.class) {
                field.set(t, new BigDecimal(value));
            }
        } else if (type == Boolean.class) {
            field.set(t, BooleanUtils.toBoolean(value));
        } else if (type == Date.class) {
            //
            field.set(t, value);
        } else if (type == String.class) {
            field.set(t, value);
        } else {
            Constructor<?> constructor = type.getConstructor(String.class);
            field.set(t, constructor.newInstance(value));
        }
    }

    private static String getCellValue(Cell cell) {
        if (cell == null) {
            return "";
        }
        if (cell.getCellType() == Cell.CELL_TYPE_NUMERIC) {
            if (HSSFDateUtil.isCellDateFormatted(cell)) {
                return HSSFDateUtil.getJavaDate(cell.getNumericCellValue()).toString();
            } else {
                return new BigDecimal(cell.getNumericCellValue()).toString();
            }
        } else if (cell.getCellType() == Cell.CELL_TYPE_STRING) {
            return StringUtils.trimToEmpty(cell.getStringCellValue());
        } else if (cell.getCellType() == Cell.CELL_TYPE_FORMULA) {
            return StringUtils.trimToEmpty(cell.getCellFormula());
        } else if (cell.getCellType() == Cell.CELL_TYPE_BLANK) {
            return "";
        } else if (cell.getCellType() == Cell.CELL_TYPE_BOOLEAN) {
            return String.valueOf(cell.getBooleanCellValue());
        } else if (cell.getCellType() == Cell.CELL_TYPE_ERROR) {
            return "ERROR";
        } else {
            return cell.toString().trim();
        }

    }

    public static <T> void writeExcel(HttpServletResponse response, List<T> dataList, Class<T> cls) {
        Field[] fields = cls.getDeclaredFields();
        List<Field> fieldList = Arrays.stream(fields)
                .filter(field -> {
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null && annotation.col() > 0) {
                        field.setAccessible(true);
                        return true;
                    }
                    return false;
                }).sorted(Comparator.comparing(field -> {
                    int col = 0;
                    ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                    if (annotation != null) {
                        col = annotation.col();
                    }
                    return col;
                })).collect(Collectors.toList());

        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet sheet = wb.createSheet("Sheet1");
        AtomicInteger ai = new AtomicInteger();
        {
            Row row = sheet.createRow(ai.getAndIncrement());
            AtomicInteger aj = new AtomicInteger();
            //写入头部
            fieldList.forEach(field -> {
                ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                String columnName = "";
                if (annotation != null) {
                    columnName = annotation.value();
                }
                Cell cell = row.createCell(aj.getAndIncrement());

                CellStyle cellStyle = wb.createCellStyle();
                cellStyle.setFillForegroundColor(IndexedColors.WHITE.getIndex());

                Font font = wb.createFont();
                cellStyle.setFont(font);
                cell.setCellStyle(cellStyle);
                cell.setCellValue(columnName);
            });
        }
        if (CollectionUtils.isNotEmpty(dataList)) {
            dataList.forEach(t -> {
                Row row1 = sheet.createRow(ai.getAndIncrement());
                row1.setHeight((short) (15.625*150));

                AtomicInteger aj = new AtomicInteger();
                fieldList.forEach(field -> {
                    Class<?> type = field.getType();
                    Object value = "";
                    try {
                        value = field.get(t);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                    Cell cell = row1.createCell(aj.getAndIncrement());
                    if (value != null) {
//                        转换字段
                        String targetStr = value.toString();
//                        需要载入的图片文件,需要判定是不是图片,在这里使用了字符串中包含的内容进行了判定,可以根据后缀或者是定义模型中直接指定
                        if (targetStr.contains("/upload/")) {
                            setPhoto(wb, sheet, aj.get(), ai.get(), targetStr);
                        } else {
                            cell.setCellValue(targetStr);
                        }

                    }
                });
            });
        }
        //冻结窗格
        wb.getSheet("Sheet1").createFreezePane(0, 1, 0, 1);
        //浏览器下载excel
        buildExcelDocument("汇总.xls", wb, response);
        //生成excel文件
//        buildExcelFile(".\\default.xlsx",wb);
    }

    /**
     * 浏览器下载excel
     *
     * @param fileName
     * @param wb
     * @param response
     */

    private static void buildExcelDocument(String fileName, Workbook wb, HttpServletResponse response) {
        try {
            response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
            response.setHeader("Content-Disposition", "attachment;filename=" + URLEncoder.encode(fileName, "utf-8"));
            response.flushBuffer();
            wb.write(response.getOutputStream());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 生成excel文件
     *
     * @param path 生成excel路径
     * @param wb
     */
    private static void buildExcelFile(String path, Workbook wb) {

        File file = new File(path);
        if (file.exists()) {
            file.delete();
        }
        try {
            wb.write(new FileOutputStream(file));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * @Title: @Description: excel生成图片工具 @param @return @throws
     * 听说这个地方需要单例,createDrawingPatriarch只能有一个
     * 但是为啥我每次调用都可以呢
     */
    private static void setPhoto(HSSFWorkbook workbook, HSSFSheet sheet, int a, int b, String file) {
        HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
        BufferedImage bufferImg = null;
        ByteArrayOutputStream byteArrayOut = new ByteArrayOutputStream();
        try {
            sheet.setColumnWidth((a-1),(252*80));
//            临时这么一写,可以读配置,需要将http转换为本地的文件才可以进行读写
            file = file.replace("图片地址", "D:/file/java/public/");
            File l = new File(file);

            bufferImg = ImageIO.read(l);
//              bufferImg = ImageIO.read(new File(ClassUtils.getDefaultClassLoader().getResource("static").getPath()
//              + temperatureRecord.getPhotoUrl()));
            ImageIO.write(bufferImg, "jpg", byteArrayOut);
            // anchor主要用于设置图片的属性
            HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0, 1023, 255, (short) (a-1), b-1, (short) (a-1), b-1);
            // 插入图片
            patriarch.createPicture(anchor,
                    workbook.addPicture(byteArrayOut.toByteArray(), HSSFWorkbook.PICTURE_TYPE_JPEG));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

定义一个注解接口。

package com.x.x.model;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 自定义实体类所需要的bean(Excel属性标题、位置等)
 *
 * @author Lynch
 *
 */
@Target({ElementType.FIELD})
@Retention(RetentionPolicy.RUNTIME)
@Documented
//自定义注解自动继承了java.lang.annotation.Annotation接口
public @interface ExcelColumn {
    /**
     * Excel标题
     *
     * @return
     * @author Lynch
     */
    String value() default "";

    /**
     * Excel从左往右排列位置
     *
     * @return
     * @author Lynch
     */
    int col() default 0;
}

定义一个Excel写入的model,如下所示。

package com.x.x.model;

import lombok.Data;

import java.time.LocalDateTime;

@Data
public class User {
    @ExcelColumn(value = "唯一序号",col = 1)
    private Integer UUid;
    @ExcelColumn(value = "用户id",col = 2)
    private Integer userId;
    @ExcelColumn(value = "提交时间",col = 16)
    private LocalDateTime createdAt;

}

工具类的调用

    /**
     * 导出Excel文件,当前未确认的订单为准
     */
    @GetMapping("/export-user-excel")
    public void exportUserExcel(HttpServletRequest request, HttpServletResponse response) {
        // list数据模型
        List<UserInfo> userList = new ArrayList<>();
        for (WxUserRebackRecord item : userList) {
            QueryWrapper<UserInfo> bankInfoQueryWrapper = new QueryWrapper<>();
            UserInfo userNeedCash = new UserNeedCash();
            UserInfo.setUUid("id");
            UserInfo.setUserId("uid");
            UserInfo.setCreatedAt("time");
            userList.add(userNeedCash);
        }
        ExcelUtils.writeExcel(response, userNeedCashList, UserNeedCash.class);
        System.out.println("____________________Excel complete_________________");
    }

链接