package com.lxyer.excel.poi;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.poifs.filesystem.OfficeXmlFileException;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.lang.reflect.Field;
import java.text.SimpleDateFormat;
import java.util.*;

/**
	下载示例
	private static boolean downloadExcel(Workbook wb, String xlsName, HttpServletRequest request, HttpServletResponse response) throws IOException{
			if(request.getHeader("user-agent").indexOf("MSIE") != -1) {
				xlsName = java.net.URLEncoder.encode(xlsName,"utf-8") + ".xls";
			} else {
			    xlsName = new String(xlsName.getBytes("utf-8"),"iso-8859-1")+ ".xls";
			}
			OutputStream os = response.getOutputStream();
			response.setContentType("application/vnd.ms-excel");
			response.setHeader("Content-disposition", "attachment;filename="+xlsName);

			wb.write(os);
			return true;
	}

 * 使用poi报表导出工具类
 * 把poi的一个调用接口抽出来，便于导出功能的管理
 * @author LiangXianYou lxy208@126.com
 * @param
 *
 */
public class ExcelKit {

    /**
     * Excels导出多个sheet
     *
     * @author LiangXianYou
     * @date 2015-6-16 下午5:56:56
     */
    //map:data,sheetName,hds,hdNames,xlsName;
    public static <T> Workbook exportExcels(List<Map<String, Object>> list) throws Exception {

        Workbook wb = new XSSFWorkbook();            //创建工作薄
        for (int i = 0; i < list.size(); i++) {
            Map<String, Object> map = list.get(i);
            Sheet sheet = wb.createSheet();                //创建工作表
            String sheetName = (String) map.get("sheetName");
            wb.setSheetName(i, sheetName);
            //写入表头---Excel的第一行数据
            Row nRow = sheet.createRow(0);                //创建行
            String[] hdNames = (String[]) map.get("hdNames");
            for (int j = 0; j < hdNames.length; j++) {
                Cell nCell = nRow.createCell(j);            //创建单元格
                nCell.setCellValue(hdNames[j]);
            }

            //写入每一行数据---一条记录就是一行数据
            @SuppressWarnings("unchecked")
            List<T> data = (List<T>) map.get("data");
            String[] hds = (String[]) map.get("hds");
            for (int j = 0; j < data.size(); j++) {
                for (int k = 0; k < hds.length; k++) {
                    Object o = getFieldValue(data.get(j), hds[k]);    //得到列的值
                    data2Excel(sheet, o, j + 1, k);                    //将值写入Excel
                }
            }
        }

        return wb;
    }

    /**
     * 参数说明：
     * list：list数据集合
     * hdNames：表头需要显示的名称
     * hds：表头对应的对象属性名称，和 hdNames一一对应
     * xlsName：导出Excel的预定义名称
     * request:	HttpServletRequest
     * response：HttpServletResponse
     * 通过数据构建Excel
     *
     * @throws Exception
     * @author LiangXianYou
     * @date 2015-3-13 上午11:00:30
     */
    public static <T> Workbook exportExcel(List<T> list, String[] hdNames, String[] hds) throws Exception {

        Workbook wb = new XSSFWorkbook();            //创建工作薄
        Sheet sheet = wb.createSheet();                //创建工作表
        sheet.autoSizeColumn((short) 0);            //自适应宽度
        //写入表头---Excel的第一行数据
        Row nRow = sheet.createRow(0);                //创建行
        for (int i = 0; i < hdNames.length; i++) {
            Cell nCell = nRow.createCell(i);            //创建单元格
            nCell.setCellValue(hdNames[i]);
        }

        //写入每一行数据---一条记录就是一行数据
        for (int i = 0; i < list.size(); i++) {
            for (int j = 0; j < hds.length; j++) {
                Object o = getFieldValue(list.get(i), hds[j]); //得到列的值
                data2Excel(sheet, o, i + 1, j); //将值写入Excel
            }
        }
        return wb;
    }


    /**
     * 通过泛型实例对象得到某一字段值
     *
     * @author LiangXianYou
     * @date 2015-3-13 上午10:53:32
     */
    private static <T> Object getFieldValue(T t, String fieldName) throws Exception {
        Object v;

        if (t == null) {
            v = null;
        } else if (t instanceof Map) {
            v = ((Map) t).get(fieldName); //得到列的值
        } else {
            Field field = t.getClass().getDeclaredField(fieldName);
            field.setAccessible(true); //暴力反射
            v = field.get(t); //得到字段数据的值
        }

        return v;
    }

    /**
     * 将数据写到Excel中
     *
     * @author LiangXianYou
     * @date 2015-3-13 上午10:37:55
     */
    private static void data2Excel(Sheet sheet, Object o, Integer r, Integer c) {
        //通过获得sheet中的某一列，有得到，没有创建
        Row nRow = sheet.getRow(r);
        if (nRow == null) {
            nRow = sheet.createRow(r);
        }
        Cell nCell = nRow.createCell(c);

        //根据不同类型进行转化，如有其它类型没有考虑周全的，使用发现的时候添加
        if (o instanceof Integer) nCell.setCellValue((Integer) o);
        else if (o instanceof Double) nCell.setCellValue((Double) o);
        else if (o instanceof Float) nCell.setCellValue((Float) o);
        else if (o instanceof String) nCell.setCellValue((String) o);
        else if (o instanceof Date) nCell.setCellValue(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(o));
        else if (o instanceof Calendar) nCell.setCellValue((Calendar) o);
        else if (o instanceof Boolean) nCell.setCellValue((Boolean) o);
        else if (o == null) nCell.setCellValue("");
        else nCell.setCellValue(o + "");
    }

    //======================= 读取excel ===============================

    //read excel head
    public static Map readExcelHead(File file, String[] fields) throws IOException {
        List<Map> list = readExcel(file, fields, 1, null);
        return list.size() > 0 ? list.get(0) : new HashMap();
    }

    //read excel head by sheetName
    public static Map readExcelHead(File file, String[] fields, String sheetName) throws IOException {
        List<Map> list = readExcel(file, fields, 1, sheetName);
        return list.size() > 0 ? list.get(0) : new HashMap();
    }

    //read excel sheet[0]
    public static List<Map> readExcel(File file, String[] fields) throws IOException {
        return readExcel(file, fields, -1, null);
    }

    //read excel sheet[0] no fields
    public static List<Map> readExcel(File file) throws IOException {
        return readExcel(file, null, -1, null);
    }

    //read excel by sheetName
    public static List<Map> readExcel(File file, String[] fields, String sheetName) throws IOException {
        return readExcel(file, fields, -1, sheetName);
    }

    //read excel by sheetName no fields
    public static List<Map> readExcel(File file, String sheetName) throws IOException {
        return readExcel(file, null, -1, sheetName);
    }

    //read excel all sheet
    public static Map<String, List<Map>> readExcelAll(File file, String[] fields) throws IOException {
        return readExcelAll(file, fields, -1);
    }

    //read all excel no fields
    public static Map<String, List<Map>> readExcelAll(File file) throws IOException {
        return readExcelAll(file, null, -1);
    }

    //read excel sheet[0]
    private static List<Map> readExcel(File file, String[] fields, int lastRowNum, String sheetName) throws IOException {
        Workbook wk = getWorkbook(file);
        Sheet sheet = sheetName == null ? wk.getSheetAt(0) : wk.getSheet(sheetName);
        if (sheet == null) throw new OfficeXmlFileException("sheet[" + sheetName + "] can't findList");

        if (lastRowNum < 0 || lastRowNum > sheet.getLastRowNum()) {
            lastRowNum = sheet.getLastRowNum();
        }
        return readExcel(sheet, fields, lastRowNum);
    }

    /**
     * read excel all sheet,
     * can read excel 2007+ and 2007-
     *
     * @param file
     * @param fields
     * @param lastRowNum
     * @return
     * @throws IOException
     */
    private static Map<String, List<Map>> readExcelAll(File file, String[] fields, int lastRowNum) throws IOException {
        Workbook wk = getWorkbook(file);

        Map<String, List<Map>> data = new LinkedHashMap<>();
        //reading all sheet
        for (int i = 0; i < wk.getNumberOfSheets(); i++) {
            Sheet sheet = wk.getSheetAt(i);
            List<Map> maps = readExcel(sheet, fields, lastRowNum);

            //move head
            if (lastRowNum < 0 && maps.size() > 0) {
                maps.remove(0);
            }
            data.put(sheet.getSheetName(), maps);
        }
        return data;
    }

    /**
     * read excel
     *
     * @author Lxyer 2016/8/1 10:32.
     */
    private static List<Map> readExcel(Sheet sheet, String[] fields, int lastRowNum) throws OfficeXmlFileException {
        if (lastRowNum < 0 || lastRowNum > sheet.getLastRowNum()) {
            lastRowNum = sheet.getLastRowNum();
        }

        if (fields == null || fields.length == 0) {
            return readExcel(sheet, lastRowNum);
        }

        List<Map> list = new ArrayList<>();
        int t = 0;
        r:
        for (int i = 0; i <= lastRowNum; i++) {
            Row row = sheet.getRow(i);
            if (row == null) continue;
            short cellNum = row.getLastCellNum();
            //空跳过/连续三行为空结束
            if (isEmptyRow(row, fields.length)) {
                if (t++ > 3) break;
                continue;
            }

            Map map = new HashMap();
            for (int j = 0; j < cellNum && j < fields.length; j++) {
                Cell cell = row.getCell(j);
                if (cell == null) {
                    map.put(fields[j], "");
                    continue;
                }

                if (cell.getCellTypeEnum() == CellType.NUMERIC) {
                    map.put(fields[j], (long) cell.getNumericCellValue() + "");
                } else {
                    map.put(fields[j], cell.getStringCellValue());
                }
            }
            list.add(map);
        }
        return list;
    }

    /**
     * @author Lxyer 2016/9/21 00:38.
     */
    private static List<Map> readExcel(Sheet sheet, int lastRowNum) throws OfficeXmlFileException {
        List<Map> list = new ArrayList<>();
        if (lastRowNum < 0 || lastRowNum > sheet.getLastRowNum()) {
            lastRowNum = sheet.getLastRowNum();
        }

        int t = 0;
        r:
        for (int i = 0; i <= lastRowNum; i++) {
            Row row = sheet.getRow(i);
            if (row == null) continue;
            short cellNum = row.getLastCellNum();
            //空跳过/连续三行为空结束
            if (isEmptyRow(row, 3)) {
                if (t++ > 3) break;
                continue;
            }

            Map map = new HashMap();
            for (int j = 0; j < cellNum; j++) {
                String field = (char) ((j / 26 == 0 ? ' ' : 'a') + j / 26) + "" + (char) ('a' + j % 26);
                field = field.replace(" ", "");
                Cell cell = row.getCell(j);
                if (cell == null) {
                    map.put(field, "");
                    continue;
                }

                if (cell.getCellTypeEnum() == CellType.NUMERIC) {
                    map.put(field, (long) cell.getNumericCellValue() + "");
                } else {
                    map.put(field, cell.getStringCellValue());
                }
            }
            list.add(map);
        }
        return list;
    }

    //空跳过/连续三行为空结束
    private static boolean isEmptyRow(Row row, int len) {
        for (int i = 0; i < row.getLastCellNum() && i < len; i++) {
            Cell cell = row.getCell(i);//列
            if (cell != null) {
                if (cell.getCellTypeEnum() != CellType.NUMERIC && cell.getStringCellValue() != null && !cell.getStringCellValue().isEmpty()) {
                    return false;
                } else if (cell.getCellTypeEnum() == CellType.NUMERIC && cell.getNumericCellValue() != 0) {
                    return false;
                }
            }
        }
        return true;
    }

    //get all sheet names
    public static List<String> getSheetNames(File file) throws IOException {
        Workbook wk = getWorkbook(file);
        List<String> sheetNames = new ArrayList<>();
        for (int i = 0; i < wk.getNumberOfSheets(); i++) {
            sheetNames.add(wk.getSheetAt(i).getSheetName());
        }
        return sheetNames;
    }

    private static Workbook getWorkbook(File file) throws IOException {
        Workbook wk;
        try {
            wk = new HSSFWorkbook(new FileInputStream(file));//if excel version 2007+ will throws OfficeXmlFileException
        } catch (OfficeXmlFileException e) {
            wk = new XSSFWorkbook(new FileInputStream(file));
        }

        return wk;
    }

}