Excel导出工具类（笔记）

package com.meatball.utils;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
 * @author 清风怎不知意
 * @Title: ExcelExportUtils
 * @Package com.meatball.utils
 * @Description: TODO(Excel导出工具)
 * @date 2018/8/23 9:10
 */
public class ExcelExportUtils {
    private static final Logger log = LoggerFactory.getLogger(ExcelImportUtils.class);
    //表单标题
    private  String title;
    private  Workbook workbook;
    private  SXSSFSheet sheet;
    //表格样式
    private  Map,CellStyle> styles;
    //头部标题
    private static List headList;
    //获取数据的方法
    private  List methodList;
    //需要导出的内容
    private List contents;
    //每一列数据最长的字段长度
    private List width;
    /**
     * @Description: TODO(导出Excel)
     * @param response
     * @param headerList 表头标题列表，按实际顺序传入 eg:["title","name","age","sex"]
     * @param methodList 表格对应内容请求方法列表，按表头顺序传入 eg:["标题","姓名","年龄","性别"]
     * @param contentList 数据列表，最大支持1000000行
     * @param title 表格标题
     * @throws
     */
    public  void exportExcel(HttpServletResponse response, List headerList, List methodList,List contentList,String title){
        if(contentList==null || contentList.size()<=0){
            try {
                response.sendError(500,"没有数据！");
            } catch (IOException e) {
                e.printStackTrace();
            }
            return;
        }
        if(contentList.size()>1000000){
            try {
                response.sendError(500,"数据量过大，单次导出量不得超过一百万条！");
            } catch (IOException e) {
                e.printStackTrace();
            }
            return;
        }
        this.contents = contentList;
        this.headList = headerList;
        this.methodList = methodList;
        this.title = title;
        //初始化表格
        initSheet();
        //初始化表头
        creatSheetHead();
        //填充数据
        try {
            fillSheetData();
        } catch (IllegalAccessException e) {
            //私有属性或方法不能访问
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            //方法名有错
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            //类实例化失败
            e.printStackTrace();
        }
        //调整列宽
        for(int i= 0 ;i;i++){
            sheet.setColumnWidth(i,(width.get(i)+4)*256);
        }
        //导出数据
        try {
            export(response);
        } catch (IOException e) {
            //导出失败
            e.printStackTrace();
        }
    }
    /**
     * @Description: TODO(初始化表单)
     * @param
     * @throws
     */
    private void initSheet(){
        //内存写入10000条数据，其余写入磁盘，防止内存溢出
        workbook = new SXSSFWorkbook(10000);
        styles = createStyles(workbook);
        sheet = (SXSSFSheet) workbook.createSheet(title);
        sheet.setDisplayGridlines(false);
        sheet.setPrintGridlines(false);
        sheet.setFitToPage(true);
        sheet.setHorizontallyCenter(true);
        sheet.createFreezePane(0, 1, 0, 1);
        PrintSetup printSetup = sheet.getPrintSetup();
        printSetup.setLandscape(true);
    }
    /**
     * @Description: TODO(创建表格样式)
     * @param wb
     * @throws
     */
    private Map,CellStyle> createStyles(Workbook wb){
, CellStyle> styles = new HashMap, CellStyle>();
        Font headFont = wb.createFont();
        headFont.setFontHeightInPoints((short) 12);
        headFont.setColor(IndexedColors.BLACK.getIndex());
        Font cellFont = wb.createFont();
        cellFont.setFontHeightInPoints((short) 10);
        cellFont.setColor(IndexedColors.BLACK.getIndex());
        CellStyle headCellStyle = createBorderedStyle(wb);
        headCellStyle.setWrapText(true);
        headCellStyle.setAlignment(HorizontalAlignment.CENTER);
        headCellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        headCellStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT
                .getIndex());
        headCellStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        headCellStyle.setFont(cellFont);
        styles.put("head", headCellStyle);
        CellStyle headTitleStyle = createBorderedStyle(wb);
        headTitleStyle.setWrapText(true);
        headTitleStyle.setAlignment(HorizontalAlignment.CENTER);
        headTitleStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        headTitleStyle.setFillForegroundColor(IndexedColors.GREY_25_PERCENT
                .getIndex());
        headTitleStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);
        headTitleStyle.setFont(headFont);
        styles.put("headTitle", headTitleStyle);
        CellStyle cellStyle = createBorderedStyle(wb);
        cellStyle.setWrapText(true);
        cellStyle.setAlignment(HorizontalAlignment.CENTER);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        cellStyle.setFont(cellFont);
        styles.put("cell", cellStyle);
        CellStyle urlStyle = createBorderedStyle(wb);
        Font urlFont = wb.createFont();
        urlFont.setColor(IndexedColors.BLUE.getIndex());
        urlFont.setUnderline(HSSFFont.U_SINGLE);
        urlStyle.setFont(urlFont);
        cellStyle.setWrapText(true);
        cellStyle.setAlignment(HorizontalAlignment.CENTER);
        cellStyle.setVerticalAlignment(VerticalAlignment.CENTER);
        styles.put("urlStyle", urlStyle);
        return styles;
    }
    /**
     * @Description: TODO(创建边框样式)
     * @param wb
     * @throws
     */
    private CellStyle createBorderedStyle(Workbook wb) {
        CellStyle style = wb.createCellStyle();
        style.setBorderRight(BorderStyle.THIN);
        style.setRightBorderColor(IndexedColors.BLACK.getIndex());
        style.setBorderBottom(BorderStyle.THIN);
        style.setBottomBorderColor(IndexedColors.BLACK.getIndex());
        style.setBorderLeft(BorderStyle.THIN);
        style.setLeftBorderColor(IndexedColors.BLACK.getIndex());
        style.setBorderTop(BorderStyle.THIN);
        style.setTopBorderColor(IndexedColors.BLACK.getIndex());
        return style;
    }
    /**
     * @Description: TODO(创建表头)
     * @param
     * @throws
     */
    private void creatSheetHead(){
        Row headRow = sheet.createRow(0);
        CellStyle headCellStyle = styles.get("head");
        for(int i = 0;i<headList.size();i++){
            Cell headCell = headRow.createCell(i);
            headCell.setCellValue(headList.get(i));
            headCell.setCellStyle(headCellStyle);
        }
    }
    /**
     * @Description: TODO(填充数据 )
     * @param
     * @throws
     */
    private void fillSheetData() throws IllegalAccessException, InstantiationException, NoSuchMethodException, InvocationTargetException {
        int rowNum = 1;
        width = new ArrayList<>();
        CellStyle cellStyle = styles.get("cell");
        Class clazz = contents.get(0).getClass();
        for(int i = 0;i<contents.size();i++){
            Object obj = contents.get(i);
            Row row = sheet.createRow(i+rowNum);
            row.setHeightInPoints(2*sheet.getDefaultRowHeightInPoints());
            for(int j= 0;j<methodList.size();j++){
                if(methodList.get(j)==null || "".equalsIgnoreCase(methodList.get(j)))
                    continue;
                Method method = clazz.getMethod(methodList.get(j));
                Cell itemCell = row.createCell(j);
                String s = method.invoke(obj) == null ? "" : String.valueOf(method.invoke(obj));
                if(width.size()>=(j+1)){
                    width.set(j,width.get(j)>s.length() ? width.get(j) : s.length());
                }else {
                    width.add(s.length());
                }
                itemCell.setCellValue(s);
                itemCell.setCellStyle(cellStyle);
            }
        }
    }
    /**
     * @Description: TODO(导出数据)
     * @param response
     * @throws
     */
    private void export(HttpServletResponse response) throws IOException {
        response.setContentType("application/vnd.ms-excel");
        String excelFileName = title + ".xlsx";
        response.addHeader("Content-Disposition", "attachment;filename="
                + new String(excelFileName.getBytes("GB2312"), "iso8859-1"));
        OutputStream ouputStream = response.getOutputStream();
        workbook.write(ouputStream);
        ouputStream.flush();
        ouputStream.close();
    }
}