ExcelUtil.java

package com.meishu.util.excel;

import com.baomidou.mybatisplus.core.toolkit.CollectionUtils;
import lombok.extern.slf4j.Slf4j;
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.HSSFDateUtil;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.http.MediaType;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.context.request.ServletRequestAttributes;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.stream.Collectors;
import java.util.stream.Stream;

/**
 * Excel工具
 *
 * @author DengMin
 * @date 2019/08/27 13:57
 **/
@Slf4j
public class ExcelUtil {

    private final static String EXCEL2003 = "xls";

    private final static String EXCEL2007 = "xlsx";

    /**
     * 导入excel文件
     * @param path
     * @param cls
     * @param file
     * @param <T>
     * @return
     */
    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.info("上传文件格式不正确");
//            throw new HTTPException(10022);
        }

        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) {
                Map<String, List<Field>> classMap = new HashMap<>();
                List<Field> fields = Stream.of(cls.getDeclaredFields()).collect(Collectors.toList());
                fields.forEach(field -> {
                    ExcelColumnUtil annotation = field.getAnnotation(ExcelColumnUtil.class);
                    if (annotation != null) {
                        String value = annotation.value();
                        if(StringUtils.isBlank(value)) {
                            return;
                        }

                        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<>();
                //默认读取第一个sheet
                Sheet sheet = workbook.getSheetAt(0);

                boolean firstRow = true;
                for (int i = 0; i <= sheet.getLastRowNum(); i++) {
                    Row row = sheet.getRow(i);
                    //提取标题
                    if (firstRow) {
                        for (int j = 0; 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 = 0; 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) {
                                            e.printStackTrace();
                                            log.error(String.format("reflect field:%s value:%s exception!", x.getName(), cellValue), e);
                                        }
                                    });
                                }
                            }

                            if(!allBlank) {
                                dataList.add(t);
                            }
                        } catch (Exception e) {
                            e.printStackTrace();
                            log.error(String.format("parse row:%s exception!", i), e);
                        }
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
            log.error(String.format("parse excel exception!"), e);
        } finally {
            if (workbook != null) {
                try {
                    workbook.close();
                } catch (Exception e) {
                    e.printStackTrace();
                    log.error(String.format("parse excel exception!"), e);
                }
            }
        }
        return dataList;
    }

    /**
     * 导出excel文件
     * @param list
     * @param cls
     * @param <T>
     */
    public static <T> void writeExcel(List<T> list, Class cls) {
        ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) RequestContextHolder.getRequestAttributes();
        HttpServletResponse response = servletRequestAttributes.getResponse();
        Field[] fields = cls.getDeclaredFields();
        List<Field> fieldList = Arrays.stream(fields).filter(field -> {
            ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
            if(annotation != null) {
                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());

        Workbook wb = new XSSFWorkbook();
        Sheet sheet = wb.createSheet();
        AtomicInteger ai = new AtomicInteger();
        {
            Row row = sheet.createRow(ai.getAndIncrement());
            AtomicInteger at = new AtomicInteger();
            fieldList.forEach(field -> {
                ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                String columnName = "";
                if (annotation != null) {
                    columnName = annotation.value();
                }
                Cell cell = row.createCell(at.getAndIncrement());
                CellStyle cellStyle = wb.createCellStyle();
                cellStyle.setFillForegroundColor(IndexedColors.PALE_BLUE.getIndex());
                Font font = wb.createFont();
                font.setBoldweight(Font.BOLDWEIGHT_BOLD);
                cellStyle.setFont(font);
                cell.setCellStyle(cellStyle);
                cell.setCellValue(columnName);
            });

            if (list != null) {
                list.forEach(data -> {
                    Row r = sheet.createRow(ai.getAndIncrement());
                    AtomicInteger a = new AtomicInteger();
                    fieldList.forEach(field -> {
                        try {
                            Class<?> type = field.getType();
                            Object value = field.get(data);
                            Cell cell = r.createCell(a.getAndIncrement());
                            if (value != null) {
                                cell.setCellValue(value.toString());
                            }
                        } catch (IllegalAccessException e) {
                            e.printStackTrace();
                        }
                    });
                });
                for (int i = 0; i < list.size(); i++) {
                    sheet.autoSizeColumn(i);
                }
            }
            String fileName = String.valueOf(new Date().getTime());
            buildExcelDocument(fileName + "." + EXCEL2007, wb, response);
        }
    }


    private static void setStyle(CellStyle cellStyle) {
        // 水平居中
        cellStyle.setAlignment(CellStyle.ALIGN_CENTER);
        // 垂直居中
        cellStyle.setVerticalAlignment(CellStyle.ALIGN_CENTER);
        // 边框
        cellStyle.setBorderTop(CellStyle.BORDER_THIN);
        // 边框
        cellStyle.setBorderLeft(CellStyle.BORDER_THIN);
        // 边框
        cellStyle.setBorderRight(CellStyle.BORDER_THIN);
        // 边框
        cellStyle.setBorderBottom(CellStyle.BORDER_THIN);
    }

    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 (DateUtil.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();
        }
    }

    private static void buildExcelDocument(String fileName, Workbook wb, HttpServletResponse response){
        try {
            response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
            response.setHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode(fileName, "utf-8"));
            response.flushBuffer();
            wb.write(response.getOutputStream());
        } catch (IOException e) {
            log.error(String.format("downLoad excel exception"), e);
        }
    }

    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) {
            log.error(String.format("downLoad excel exception"), e);
        }
    }
}