Excel簡單工具類(導出)

package com.by.demo.utils;

import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.lang.reflect.Field;
import java.util.List;

/*
 *Ex生成
 * */
public class ExUtils {

    public static HSSFWorkbook ExCreate(List<String> tableNames, List<?> objects, Integer row, Integer col) throws Exception {
        // 1.創建一個workbook，對應一個Excel文件
        HSSFWorkbook hssfWorkbook = new HSSFWorkbook();
        // 2.在workbook中添加一個sheet，對應Excel中的一個sheet
        HSSFSheet hssfSheet = hssfWorkbook.createSheet();
        // 3.在sheet中添加表頭
        HSSFRow hssfRow = hssfSheet.createRow(0);
        // 4.創建單元格，設置值表頭，設置表頭居中
//        HSSFCellStyle hssfCellStyle = hssfWorkbook.createCellStyle();
//        hssfCellStyle.setAlignment();
        if (tableNames != null && tableNames.size() != 0) {
            for (int i = 0; i < tableNames.size(); i++) {
                hssfRow.createCell(i).setCellValue(tableNames.get(i));
            }
        }
        Field[] fields = null;
        Field ft = null;
        if (objects == null) {
            return hssfWorkbook;
        }
        if (tableNames == null || tableNames.size() == 0) {
            fields = objects.get(0).getClass().getDeclaredFields();
            for (int i = 0; i < fields.length; i++) {
                hssfRow.createCell(i).setCellValue(fields[i].getName().toString());
            }
        }
        for (int i = 0; i < objects.size(); i++) {
            hssfRow = hssfSheet.createRow(i + 1);
            fields = objects.get(i).getClass().getDeclaredFields();
            for (int j = 0; j < fields.length; j++) {
                ft = fields[j];
                ft.setAccessible(true);
                hssfRow.createCell(j).setCellValue(ft.get(objects.get(i)).toString());
            }
        }
        return hssfWorkbook;
    }

    public static void downex(String fileName, HttpServletResponse response, HSSFWorkbook hssfWorkbook) throws IOException {
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        hssfWorkbook.write(byteArrayOutputStream);
        byte[] bytes = byteArrayOutputStream.toByteArray();
        InputStream inputStream = new ByteArrayInputStream(bytes);
        response.reset(); // 必要地清除response中的緩存信息
        // 在瀏覽器提示用戶是保存還是下載
        response.setContentType("application/octet-stream; charset=UTF-8");// 根據個人需要,這個是下載文件的類型
        response.setHeader("Content-Disposition", "attachment;filename="
                + new String((fileName + ".xls").getBytes(), "iso-8859-1"));
        OutputStream outputStream = response.getOutputStream();
        byte[] content = new byte[1024];
        int length;
        while ((length = inputStream.read(content)) != -1) {
            outputStream.write(content, 0, length);
        }
        inputStream.close();
        outputStream.close();
    }

}