自定义注解实现Execl的导入导出

自定义注解实现Execl导入导出

悲伤，我是Java开发程序员，竟然被说是做运维的了。我是开发开发开发！！！！

写个笔记，记录一下以前的execl导入导出功能代码

pom坐标

此处使用常规版本3.9，未使用4.0版本，原因部分API已删除或过时

	<dependency>
			<groupId>org.apache.poi</groupId>
			<artifactId>poi-ooxml</artifactId>
			<version>3.9</version>
	</dependency>

自定义注解

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.FIELD)
public @interface ExcelAttribute {
    /** 对应的列名称 */
    String name() default "";

    /** 列序号 */
    int sort();

    /** 字段类型对应的格式 */
    String format() default "";

}

导入工具类

public class ExcelImportUtil<T> {
	//泛型实体clzz
    private Class clazz;
    private Field fields[];
	
    public ExcelImportUtil(Class clazz) {
        this.clazz = clazz;
        fields = clazz.getDeclaredFields();
    }

    /**
     * 基于注解读取excel
     *rowIndex 开始行号
     *cellIndex开始单元格
     */
    public List<T> readExcel(InputStream is, int rowIndex, int cellIndex) {
        List<T> list = new ArrayList<T>();
        T entity = null;
        try {
            XSSFWorkbook workbook = new XSSFWorkbook(is);
            Sheet sheet = workbook.getSheetAt(0);
            // 不准确
            int rowLength = sheet.getPhysicalNumberOfRows();
//            System.out.println(sheet.getLastRowNum());
            for (int rowNum = rowIndex; rowNum <= rowLength; rowNum++) {
                Row row = sheet.getRow(rowNum);
                if (row!=null){

                    entity = (T) clazz.newInstance();
                    for (int j = cellIndex; j < row.getPhysicalNumberOfCells(); j++) {
                        Cell cell = row.getCell(j);
                        for (Field field : fields) {
                            if (field.isAnnotationPresent(ExcelAttribute.class)) {
                                field.setAccessible(true);
                                ExcelAttribute ea = field.getAnnotation(ExcelAttribute.class);
                                if (j == ea.sort()) {
                                    field.set(entity, covertAttrType(field, cell));
                                }
                            }
                        }
                    }
                    list.add(entity);


                }

            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return list;
    }


    /**
     * 类型转换 将cell 单元格格式转为 字段类型
     */
    private Object covertAttrType(Field field, Cell cell) throws Exception {
        String fieldType = field.getType().getSimpleName();
        if ("String".equals(fieldType)) {
            return getValue(cell);
        } else if ("Date".equals(fieldType)) {
            return new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").parse(getValue(cell));
        } else if ("int".equals(fieldType) || "Integer".equals(fieldType)) {
            return Integer.parseInt(getValue(cell));
        } else if ("double".equals(fieldType) || "Double".equals(fieldType)) {
            return Double.parseDouble(getValue(cell));
        } else {
            return null;
        }
    }


    /**
     * 格式转为String
     *
     * @param cell
     * @return
     */
    public String getValue(Cell cell) {
        if (cell == null) {
            return "";
        }
        switch (cell.getCellType()) {
            case Cell.CELL_TYPE_STRING:
                return cell.getRichStringCellValue().getString().trim();
            case Cell.CELL_TYPE_NUMERIC:
                if (DateUtil.isCellDateFormatted(cell)) {
                    Date dt = DateUtil.getJavaDate(cell.getNumericCellValue());
                    return new SimpleDateFormat("yyyy-MM-dd hh:mm:ss").format(dt);
                } else {
                    // 防止数值变成科学计数法
                    String strCell = "";
                    Double num = cell.getNumericCellValue();
                    BigDecimal bd = new BigDecimal(num.toString());
                    if (bd != null) {
                        strCell = bd.toPlainString();
                    }
                    // 去除 浮点型 自动加的 .0
                    if (strCell.endsWith(".0")) {
                        strCell = strCell.substring(0, strCell.indexOf("."));
                    }
                    return strCell;
                }
            case Cell.CELL_TYPE_BOOLEAN:
                return String.valueOf(cell.getBooleanCellValue());
            default:
                return "";
        }
    }
}

导出工具类

public class ExcelExportUtil<T> {
	 // 开始行号
    private int rowIndex;
    //风格索引，使用哪一行最为模板风格
    private int styleIndex;
    //泛型 实体clzz
    private Class clazz;
    private Field fields[];

    public ExcelExportUtil(Class clazz, int rowIndex, int styleIndex) {
        this.clazz = clazz;
        this.rowIndex = rowIndex;
        this.styleIndex = styleIndex;
        fields = clazz.getDeclaredFields();
    }

    /**
     * 基于注解导出
     *is execl模板
     *objs 数据
     *fileName 文件名
     */
    public void export(HttpServletResponse response, InputStream is, List<T> objs, String fileName) throws Exception {

        XSSFWorkbook workbook = new XSSFWorkbook(is);
        Sheet sheet = workbook.getSheetAt(0);

        CellStyle[] styles = getTemplateStyles(sheet.getRow(styleIndex));

        AtomicInteger datasAi = new AtomicInteger(rowIndex);
        for (T t : objs) {
            Row row = sheet.createRow(datasAi.getAndIncrement());
            for (int i = 0; i < styles.length; i++) {
                Cell cell = row.createCell(i);
                cell.setCellStyle(styles[i]);
                for (Field field : fields) {
                    if (field.isAnnotationPresent(ExcelAttribute.class)) {
                        field.setAccessible(true);
                        ExcelAttribute ea = field.getAnnotation(ExcelAttribute.class);
                        if (i == ea.sort()) {
                            if (field.get(t)==null){
                                continue;
                            }
                            cell.setCellValue(field.get(t).toString());
                        }
                    }
                }
            }
        }
        fileName = URLEncoder.encode(fileName, "UTF-8");
        response.setContentType("application/octet-stream");
        response.setHeader("content-disposition", "attachment;filename=" + new String(fileName.getBytes("ISO8859-1")));
        response.setHeader("filename", fileName);
        workbook.write(response.getOutputStream());
    }
      public CellStyle[] getTemplateStyles(Row row) {
        CellStyle[] styles = new CellStyle[row.getLastCellNum()];
        for (int i = 0; i < row.getLastCellNum(); i++) {
            styles[i] = row.getCell(i).getCellStyle();
        }
        return styles;
    }
}

使用方法

//导出方法
List<User> data=new ArrayList<User>();   
ExcelExportUtil<User> excelExportUtil = new ExcelExportUtil<>(User.class, 1, 0);
        ClassPathResource classPathResource = new ClassPathResource("templates/user.xlsx");
        try ( InputStream inputStream =classPathResource.getInputStream()) {
            excelExportUtil.export(response, data, "导出结果.xlsx");
        } catch (Exception e) {
            e.printStackTrace();
        }

//导入方法
 ExcelImportUtil<User> excelUtil = new ExcelImportUtil<User>(User.class);
 List<User> userList = excelUtil.readExcel(file.getInputStream(), 1, 0);