利用模板方法模式导出Excel文件

poi版本为3.15，jdk为1.7（poi 4.1.0与jdk1.7不兼容）

数据库表与测试结果

页面按钮（其中在页面加载完毕函数中为按钮绑定点击事件，点击事件请求后台，后台以流的方式响应用户一个文件）

 Controller

@RequestMapping(value = "/exportExcel")
@ResponseBody
public void exportExcel(@RequestParam Map<String, Object> params, Model model, HttpServletRequest request, HttpServletResponse resp) {
	itemContentService.export(params, request, resp);
}

 service接口

package com.alphajuns.ssm.service;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.Map;

public interface ItemContentService {

    public void export(Map<String, Object> params, HttpServletRequest request, HttpServletResponse resp);

}

service实现类

package com.alphajuns.ssm.service.impl;

import com.alphajuns.ssm.service.ItemContentService;
import com.alphajuns.ssm.service.ItemContentSheetService;
import com.alphajuns.ssm.util.AbstractExcelHelper;
import com.alphajuns.ssm.util.AbstractExcelSheetHelper;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.Map;

@Service
public class ItemContentServiceImpl extends AbstractExcelHelper implements ItemContentService {

    @Autowired
    ItemContentSheetService itemContentSheetService;

    @Override
    public void export(Map<String, Object> params, HttpServletRequest request, HttpServletResponse resp) {
        exportExcel(params, request, resp);
    }

    @Override
    protected void init() {
        if (excelSheets == null || excelSheets.size() == 0) {
            synchronized (this) {
                if (excelSheets == null || excelSheets.size() == 0) {
                    excelSheets = new ArrayList<AbstractExcelSheetHelper>();
                    excelSheets.add((AbstractExcelSheetHelper) itemContentSheetService);
                }
            }
        }
    }

    @Override
    protected String getSheetName() {
        return "分类列表";
    }

    @Override
    protected Map<String, String> getMainHeader() {
        return null;
    }

    @Override
    protected String getFilename(Map<String, Object> params) {
        Date date = new Date();
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
        String time = df.format(date);
        return "分类列表_" + time + ".xls";
    }

    @Override
    protected List<Map<String, ?>> getMainRecord(Map<String, Object> params) {
        return null;
    }
}

抽象的Excel帮助类

package com.alphajuns.ssm.util;

import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

/**
 * 导出excel的帮助类
 *
 */
public abstract class AbstractExcelHelper {
    protected List<AbstractExcelSheetHelper> excelSheets;

    public void exportExcel(Map<String, Object> params, HttpServletRequest request, HttpServletResponse resp) {
        resp.setContentType("application/msexcel");
        resp.setCharacterEncoding("UTF-8");
        OutputStream out = null;
        String filename = getFilename(params);

        init();

        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet(getSheetName());
        int nextRow = insertMainRecord(getMainRecord(params), getMainHeader(), workbook, sheet, 0);

        int i = 0;
        for(AbstractExcelSheetHelper excelSheet: excelSheets) {
            excelSheet.createSheet(params, workbook, i, i == 0 ? nextRow : 0);
            i++;
        }

        try {
            String agent = (String)request.getHeader("USER-AGENT");
            if(agent != null && agent.toLowerCase().indexOf("firefox") > 0) {
                resp.setHeader("Content-Disposition","attachment; filename=" + new String(filename.getBytes("GB2312"),"ISO-8859-1"));
            } else {
                resp.setHeader("Content-Disposition","attachment; filename=" + URLEncoder.encode(filename, "UTF-8"));
            }

            out = resp.getOutputStream();
            workbook.write(out);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.flush();
                workbook.close();
                out.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    protected abstract void init();

    protected abstract String getSheetName();

    protected abstract Map<String, String> getMainHeader();

    protected abstract String getFilename(Map<String, Object> params);

    protected abstract List<Map<String,?>> getMainRecord(Map<String, Object> params);

    private int insertMainRecord(List<Map<String,?>> mapList, Map<String, String> header, HSSFWorkbook workbook, HSSFSheet sheet, int startRow) {
        int headerByRow = 3;
        HSSFCellStyle headerStyle = PoiExcelUtils.createTitleCellStyle(workbook);
        HSSFCellStyle contentStyle = PoiExcelUtils.createContentCellStyle(workbook);
        if (mapList == null || mapList.size() == 0) return startRow;
        Map<String, ?> map = mapList.get(0);
        int i = 0;
        int columnIdx = 0;
        HSSFCell headCell = null;
        HSSFCell contentCell = null;
        HSSFRow row = null;

        for (Entry<String, String> entry : header.entrySet()) {
            if (i % headerByRow == 0) {
                columnIdx = 0;
                row = sheet.createRow(startRow);
                startRow++;
            }
            headCell = row.createCell(columnIdx++);
            headCell.setCellValue(entry.getValue());
            headCell.setCellStyle(headerStyle);
            Object object = map.get(entry.getKey());
            contentCell = row.createCell(columnIdx++);
            if (object == null) {
                contentCell.setCellValue("");
            } else {
                contentCell.setCellValue(String.valueOf(object));
            }
            contentCell.setCellStyle(contentStyle);
            i++;
        }

        return ++startRow;
    }
}

抽象的Excel Sheet帮助类

package com.alphajuns.ssm.util;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import org.apache.log4j.Logger;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

/**
 * 导出excel sheet的帮助类
 *
 */
public abstract class AbstractExcelSheetHelper {
    /**
     * logger
     */
    private Logger logger = Logger.getLogger(AbstractExcelSheetHelper.class);
    public void createSheet(Map<String, Object> params, HSSFWorkbook workbook, int sheetNo, int startRow) {
        HSSFSheet sheet = null;
        int rows = 5000;
        if (sheetNo == 0) {
            sheet = workbook.getSheetAt(sheetNo);
        } else {
            sheet = workbook.createSheet(getSheetName());
        }

        Map<String, String> header = getHeader(params);

        int nextRow = insertHeaders(header, workbook, sheet, startRow);

        prepareParams(params);
        params.put("rows", rows);
        params.put("page", 1);
        /*params.put("isHandelStart", "Y");*/
        List<Map<String,?>> mapList = getRecords(params);
        int totalCount = 0;
        if(mapList!=null&&!mapList.isEmpty()){
            if (mapList.get(0).containsKey("TOTALCOUNT")) {
                Number nTotalCount = (Number) mapList.get(0).get("TOTALCOUNT");
                totalCount = nTotalCount.intValue();
            } else {
                totalCount = mapList.size();
            }
        }
        String reportMaxRow = "20000";
        int intReportMaxRow = 20000;
        if(reportMaxRow!=null && !reportMaxRow.trim().equals("")){
            intReportMaxRow = Integer.parseInt(reportMaxRow.trim());
        }
        if(totalCount>intReportMaxRow){
            String errMsg = "不能导出大于"+intReportMaxRow+"条的数据，请缩小选择范围！";
            HSSFCell contentCell = null;
            HSSFRow row = sheet.createRow(startRow);
            contentCell = row.createCell(0);
            contentCell.setCellValue(errMsg);
            logger.error(errMsg);
            return;
            //throw new ReportBusinessException(errMsg);
        }

        nextRow = this.insertRecords(mapList, header, workbook, sheet, nextRow);
        int totalPage = (int) Math.ceil((double)totalCount / rows);
        for (int i = 1; i < totalPage; i++) {
            params.put("page", i + 1);
            mapList = getRecords(params);
            nextRow = this.insertRecords(mapList, header, workbook, sheet, nextRow);
        }

        autoSizeColumn(header, sheet);
    }

    protected abstract Map<String, String> getHeader(Map<String,Object> params);

    protected abstract String getSheetName();

    protected abstract List<Map<String,?>> getRecords(Map<String, Object> params);

    protected abstract void prepareParams(Map<String, Object> params);

    private int insertHeaders(Map<String, String> header, HSSFWorkbook workbook, HSSFSheet sheet, int startRow) {
        HSSFCellStyle headerStyle = PoiExcelUtils.createTitleCellStyle(workbook);
        HSSFRow headerRow = sheet.createRow(startRow);
        HSSFCell headCell = null;
        int i = 0;
        for (Entry<String, String> entry : header.entrySet()) {
            headCell = headerRow.createCell(i);
            headCell.setCellValue(entry.getValue());
            headCell.setCellStyle(headerStyle);
            i++;
        }
        return ++startRow;
    }

    protected int insertRecords(List<Map<String,?>> mapList, Map<String, String> header, HSSFWorkbook workbook, HSSFSheet sheet, int startRow) {
        HSSFCellStyle contentStyle = PoiExcelUtils.createContentCellStyle(workbook);
        HSSFCell contentCell = null;
        for (Map<String, ?> map : mapList) {
            HSSFRow row = sheet.createRow(startRow);
            int cellIndex = 0;
            for (Entry<String, String> entry : header.entrySet()) {
                contentCell = row.createCell(cellIndex);
                Object object = map.get(entry.getKey());
                if (object == null) {
                    contentCell.setCellValue("");
                } else {
                    contentCell.setCellValue(String.valueOf(object));
                }
                contentCell.setCellStyle(contentStyle);
                cellIndex++;
            }
            startRow++;
        }

        return startRow;
    }

    protected void autoSizeColumn(Map<String, String> header, HSSFSheet sheet) {
        for (int i = 0; i < header.size(); i++) {
            sheet.autoSizeColumn(i);
        }
    }
}

某个类的抽象的Excel Sheet

package com.alphajuns.ssm.service;

import com.alphajuns.ssm.util.AbstractExcelSheetHelper;

public abstract class ItemContentSheetService extends AbstractExcelSheetHelper {
}

 Excel Sheet的具体实现类

package com.alphajuns.ssm.service.impl;

import com.alphajuns.ssm.mybatis.ItemMapper;
import com.alphajuns.ssm.service.ItemContentSheetService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

@Service
public class ItemContentSheetServiceImpl extends ItemContentSheetService {

    @Autowired
    private ItemMapper itemMapper;

    @Override
    protected Map<String, String> getHeader(Map<String, Object> params) {
        Map<String, String> header = new LinkedHashMap<String, String>();
        header.put("id", "类目ID");
        header.put("parent_id", "父类目ID");
        header.put("title", "分类名称");
        header.put("status", "状态");
        header.put("sort_order", "排列序号");
        header.put("is_parent", "是否为父类目");
        header.put("created", "创建时间");
        header.put("updated", "更新时间");
        return header;
    }

    @Override
    protected String getSheetName() {
        return "详情列表";
    }

    @Override
    protected List<Map<String, ?>> getRecords(Map<String, Object> params) {
        return itemMapper.queryItemContentCategory(params);
    }

    @Override
    protected void prepareParams(Map<String, Object> params) {

    }
}

mapper接口

List<Map<String,?>> queryItemContentCategory(Map<String, Object> params);

 mapper.xml

<select id="queryItemContentCategory" resultType="map">
        select * from tb_content_category
    </select>
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原文地址：https://www.cnblogs.com/alphajuns/p/13155867.html