【绝对好用】java poi 导入、导出excel（支持xsl、xslx）

约定不等于承诺〃 2022-10-06 04:48 109阅读 0赞

#  1、添加依赖 #

<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>

# 2、工具类 #

## ExcelColumn.java ##

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;
    
    @Target({ElementType.FIELD})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    public @interface ExcelColumn {
        /**
         * 列头名称
         * @return
         */
        String value() default "";
    
        /**
         *从1开始
         * @return
         */
        int col() default 0;
    }

## ExcelUtils.java ##

import org.apache.commons.collections4.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.HSSFWorkbook;
    import org.apache.poi.ss.usermodel.Cell;
    import org.apache.poi.ss.usermodel.CellStyle;
    import org.apache.poi.ss.usermodel.CellType;
    import org.apache.poi.ss.usermodel.DateUtil;
    import org.apache.poi.ss.usermodel.Font;
    import org.apache.poi.ss.usermodel.HorizontalAlignment;
    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.util.IOUtils;
    import org.apache.poi.xssf.streaming.SXSSFCell;
    import org.apache.poi.xssf.streaming.SXSSFRow;
    import org.apache.poi.xssf.streaming.SXSSFSheet;
    import org.apache.poi.xssf.streaming.SXSSFWorkbook;
    import org.apache.poi.xssf.usermodel.XSSFWorkbook;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.multipart.MultipartFile;
    
    import javax.servlet.ServletOutputStream;
    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.text.ParseException;
    import java.text.SimpleDateFormat;
    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.Properties;
    import java.util.concurrent.atomic.AtomicInteger;
    import java.util.stream.Collectors;
    
    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(MultipartFile file, Class<T> cls) throws IOException {
            InputStream inputStream = file.getInputStream();
            String fileName = file.getOriginalFilename();
            return readExcel(inputStream, fileName, cls);
        }
    
        public static <T> List<T> readExcel(InputStream inputStream, String fileName, Class<T> cls) {
            List<T> dataList = new ArrayList<>();
    
            Workbook workbook = null;
            try {
                if (fileName.endsWith(EXCEL2007)) {
                    workbook = new XSSFWorkbook(inputStream);
                }
                if (fileName.endsWith(EXCEL2003)) {
                    workbook = new HSSFWorkbook(inputStream);
                }
                if (workbook != null) {
                    //类映射  注解 value-->bean columns
                    Map<String, List<Field>> classMap = new HashMap<>();
                    Field[] fields = cls.getDeclaredFields();
                    for (Field field : fields) {
                        ExcelColumn annotation = field.getAnnotation(ExcelColumn.class);
                        if (annotation != null) {
                            String value = annotation.value();
                            if (StringUtils.isBlank(value)) {
                                continue;
                            }
                            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<>();
                    Sheet sheet = workbook.getSheetAt(0);//默认读取第一个sheet
    
                    boolean firstRow = true;
                    for (int i = sheet.getFirstRowNum(); i <= sheet.getLastRowNum(); i++) {
                        Row row = sheet.getRow(i);
    
                        if (firstRow) {//首行  提取注解
                            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 {
                            if (row == null) {//忽略空白行
                                continue;
                            }
    
                            try {
                                T t = cls.newInstance();
                                boolean allBlank = true;//判断是否为空白行
                                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);
                                        for (Field field : fieldList) {
                                            try {
                                                handleField(t, cellValue, field);
                                            } catch (Exception e) {
                                                log.error(String.format("reflect field:%s value:%s exception!", field.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("parse excel exception!", e);
            } finally {
                if (workbook != null) {
                    try {
                        workbook.close();
                    } catch (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);
            } else if (type.getSuperclass() == null || type.getSuperclass() == Number.class) {//数字类型
                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, getDateByStr(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 DateUtil.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(String path, List<T> dataList, Class<T> cls, String sheetName) {
            File file = new File(path);
            if (file.exists()) {
                file.delete();
            }
            try (Workbook wb = getExcelWorkbook(dataList, cls, sheetName);
                 FileOutputStream fos = new FileOutputStream(file);) {
                wb.write(fos);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    
        public static <T> void downloadExcel(HttpServletResponse response, String fileName, String sheetName, List<T> dataList, Class<T> cls) {
            try (SXSSFWorkbook workbook = getExcelWorkbook(dataList, cls, sheetName);
                 ServletOutputStream output = response.getOutputStream();) {
    
                Properties pro = System.getProperties();
                String encoding = pro.getProperty("file.encoding");
                response.reset();
                response.setCharacterEncoding(encoding);
                response.setContentType("application/vnd.ms-excel");
                response.setHeader("Access-Control-Expose-Headers", "Content-Disposition");
                response.setHeader("Content-Disposition", "attachment;filename="
                        + URLEncoder.encode(fileName, "UTF-8") + ".xlsx");
    
    
                IOUtils.write(workbook, output);
                output.flush();
            } catch (Exception ex) {
                ex.printStackTrace();
            }
    
        }
    
        public static <T> SXSSFWorkbook getExcelWorkbook(List<T> dataList, Class<T> cls, String sheetName) {
            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());
    
            SXSSFWorkbook wb = new SXSSFWorkbook(500);
            SXSSFSheet sheet = wb.createSheet(sheetName);
            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.setAlignment(HorizontalAlignment.CENTER);
    
                    Font font = wb.createFont();
                    cellStyle.setFont(font);
                    cell.setCellStyle(cellStyle);
                    cell.setCellValue(columnName);
                });
            }
    
            if (CollectionUtils.isNotEmpty(dataList)) {
                dataList.forEach(t -> {
                    SXSSFRow row = sheet.createRow(ai.getAndIncrement());
                    AtomicInteger aj = new AtomicInteger();
    
                    fieldList.forEach(field -> {
                        Class<?> type = field.getType();
    
                        Object value = "";
                        try {
                            value = field.get(t);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        SXSSFCell cell = row.createCell(aj.getAndIncrement());
    
                        if (value != null) {
                            if (type == Date.class) {
    //                            String dateValue = DateUtils.formatDate(DateUtils.stampToDate(Long.valueOf(value.toString())),"yyyy-MM-dd");;
    //                            cell.setCellValue(dateValue);
                                cell.setCellValue(stampToDate(Long.valueOf(value.toString())));
                            } else if (Number.class.isAssignableFrom(type)) {
                                cell.setCellType(CellType.NUMERIC);
                                if (type == Integer.class) {
                                    cell.setCellValue(Integer.valueOf(value.toString()));
                                } else if (type == Long.class) {
                                    cell.setCellValue(Long.valueOf(value.toString()));
                                } else if (type == Float.class) {
                                    cell.setCellValue(Float.valueOf(value.toString()));
                                } else if (type == Double.class) {
                                    cell.setCellValue(Double.valueOf(value.toString()));
                                } else if (type == BigDecimal.class) {
                                    cell.setCellValue(new BigDecimal(value.toString()).floatValue());
                                }
    
                            } else {
                                cell.setCellValue(value.toString());
                            }
                        }
                    });
                });
    
            }
    
            //冻结窗格
            sheet.createFreezePane(0, 1, 0, 1);
            return wb;
    
        }
    
        /**
         * 字符转日期
         *
         * @param dateStr
         * @return
         */
        public static Date getDateByStr(String dateStr) {
            SimpleDateFormat formatter = null;
            if (dateStr == null) {
                return null;
            } else if (dateStr.length() == 10) {
                formatter = new SimpleDateFormat("yyyy-MM-dd");
            } else if (dateStr.length() == 16) {
                formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm");
            } else if (dateStr.length() == 19) {
                formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            } else if (dateStr.length() > 19) {
                dateStr = dateStr.substring(0, 19);
                formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            } else {
                return null;
            }
            try {
                return formatter.parse(dateStr);
            } catch (ParseException e) {
                return null;
            }
        }
    
        /*
         * 将时间戳转换为时间
         */
        public static Date stampToDate(Long s) {
            Date date = new Date(s);
            return date;
        }
    
    }

#  3、使用方法 #

/**
        * 导入
        */
        private void importExcel(@RequestParam("file") MultipartFile file) throws IOException {
            List<Demo> excelList = ExcelUtils.readExcel(file, Demo.class);
        }
    
        /**
        * 导出
        */
        private void exportExcel(HttpServletResponse response) {
            List<Demo> exportList = new ArrayList<>();
            ExcelUtils.downloadExcel(response, "文件名", "sheet1", exportList, Demo.class);
        }
        
        
        static class Demo {
            @ExcelColumn(col = 1, value = "列1")
            private String column1;
            @ExcelColumn(col = 2, value = "列2")
            private String column2;
            @ExcelColumn(col = 3, value = "列3")
            private String column3;
    
            //忽略get、set代码
        }

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