package com.cn.greemes.common.util;
import cn.hutool.core.collection.CollUtil;
import cn.hutool.core.io.IoUtil;
import cn.hutool.core.util.IdUtil;
import cn.hutool.poi.excel.BigExcelWriter;
import cn.hutool.poi.excel.ExcelUtil;
import org.apache.poi.ss.usermodel.Cell;
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.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.net.URLEncoder;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.atomic.AtomicInteger;
/**
 * 文件操作
 */
public class FileUtil {
    public static final String SYS_TEM_DIR =System.getProperty("java.io.tmpdir")+ File.separator;
    public  void downloadExcel(List<Map<String, String>> list, HttpServletResponse response) throws IOException {
        String tempPath = SYS_TEM_DIR + IdUtil.fastSimpleUUID() + ".xlsx";
        File file = new File(tempPath);
        BigExcelWriter writer = ExcelUtil.getBigWriter(file);
        // 一次性写出内容，使用默认样式，强制输出标题
        writer.write(list, true);
        SXSSFSheet sheet = (SXSSFSheet)writer.getSheet();
        //上面需要强转SXSSFSheet  不然没有trackAllColumnsForAutoSizing方法
        sheet.trackAllColumnsForAutoSizing();
        //列宽自适应
       // writer.autoSizeColumnAll();
        //response为HttpServletResponse对象
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
        //test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码
        response.setHeader("Content-Disposition", "attachment;filename=file.xlsx");
        ServletOutputStream out = response.getOutputStream();
        // 终止后删除临时文件
        file.deleteOnExit();
        writer.flush(out, true);
        //此处记得关闭输出Servlet流
        IoUtil.close(out);
    }
    public  void downloadExcelBySXSSF(List<Map<String, String>> list, HttpServletResponse response) throws IOException {
        String tempPath = SYS_TEM_DIR + IdUtil.fastSimpleUUID() + ".xlsx";
        File file = new File(tempPath);
        //2.创建工作簿
         SXSSFWorkbook workbook = new SXSSFWorkbook();
        //3.构造sheet
        Sheet sheet =workbook.createSheet();
        //创建表头
        Row row = sheet.createRow(0);
        Map<String,String> mapfirst = list.get(0);
        String listHead = null;
        AtomicInteger headersAi = new AtomicInteger();
        for (String key : mapfirst.keySet()) {
           Cell cell = row.createCell(headersAi.getAndIncrement());
           cell.setCellValue(key);
        }
        AtomicInteger datasAi = new AtomicInteger(1);
        Cell cell =null;
        for(Map<String, String> map : list){
            Row dataRow = sheet.createRow(datasAi.getAndIncrement());
            int i=0;
            for (String key : map.keySet()) {
                Cell cell1 = dataRow.createCell(datasAi.getAndIncrement());
                String value= (String)map.get(key);
                cell = dataRow.createCell(i);
                cell1.setCellValue(value);
                i++;
            }
        }
        String fileName = URLEncoder.encode("用户信息.xlsx", "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());
    }
}