使用Java導出Excel案例詳解

package com.wy.common.util;

import java.io.IOException;
import java.io.OutputStream;
import java.util.List;
import java.util.Map;

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.hssf.util.Region;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;

//這是一個導出Excel的工具類
public class ExportExcelUtils{
/**
* 這是一個通用的方法,將一個map集合作爲表格內容輸入到excel中
*
* @param title
* 表格標題名
* @param headers
* 表格屬性列名數組
* @param rows
* 需要顯示的數據集合,row爲List

@SuppressWarnings("deprecation")
public void exportExcel(String title, String[] headers,List<Map> rows, String[] rowkeys, OutputStream out) {
    // 聲明一個工作薄
    HSSFWorkbook workbook = new HSSFWorkbook();
    // 生成一個表格
    HSSFSheet sheet = workbook.createSheet(title);
    // 設置表格默認列寬度爲15個字節
    sheet.setDefaultColumnWidth((short) 25);
    if(rows!=null && rows.size()>0 ){
        //判斷傳入集合數據，如爲空即不填充數據導出空Excel
        /** ----------- 生成標題     ------------*/
        //第一行寫入標題
        HSSFFont fontTitle = workbook.createFont();
        HSSFCellStyle titleStyle = workbook.createCellStyle();
        titleStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        titleStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
        fontTitle.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        fontTitle.setFontHeightInPoints((short) 16);
        titleStyle.setFont(fontTitle);
        if(headers!=null){
            //這裏作非空驗證
            sheet.addMergedRegion(new Region(0,(short)0,0,(short)(headers.length-1)));
        }
        HSSFRow rowTitle = sheet.createRow(0);
        rowTitle.setHeight((short)500);
        HSSFCell cellTitle = rowTitle.createCell(0);
        cellTitle.setCellStyle(titleStyle);
        cellTitle.setCellValue(title);

        /** ----------- 生成表頭     ------------*/
        HSSFFont fontHeader = workbook.createFont();
        fontHeader.setBoldweight(Font.BOLDWEIGHT_BOLD);
        HSSFCellStyle cstyleHeader =workbook.createCellStyle();
        cstyleHeader.setFont(fontHeader);
        cstyleHeader.setAlignment(CellStyle.ALIGN_CENTER);
        cstyleHeader.setBorderBottom(CellStyle.BORDER_THIN);
        cstyleHeader.setBorderLeft(CellStyle.BORDER_THIN);
        cstyleHeader.setBorderRight(CellStyle.BORDER_THIN);
        cstyleHeader.setBorderTop(CellStyle.BORDER_THIN);
        HSSFRow row = sheet.createRow(1);
        for (short i = 0; i < headers.length; i++) {
            HSSFCell cell = row.createCell(i);
            //cell.setCellStyle(style);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            cell.setCellStyle(cstyleHeader);
            cell.setCellValue(text);
        }

        /** ----------- 生成數據行     ------------*/
        int index = 2;
        HSSFFont fontData = workbook.createFont();
        fontData.setBoldweight(Font.BOLDWEIGHT_NORMAL);
        HSSFCellStyle cstyleData =workbook.createCellStyle();
        cstyleData.setBorderBottom(CellStyle.BORDER_THIN);
        cstyleData.setBorderLeft(CellStyle.BORDER_THIN);
        cstyleData.setBorderRight(CellStyle.BORDER_THIN);
        cstyleData.setBorderTop(CellStyle.BORDER_THIN);
        cstyleData.setFont(fontData);
        cstyleData.setAlignment(CellStyle.ALIGN_CENTER);

        /*      HSSFCellStyle cstyleData1 =workbook.createCellStyle();
        cstyleData1.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        cstyleData1.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        cstyleData1.setBorderRight(HSSFCellStyle.BORDER_THIN);
        cstyleData1.setBorderTop(HSSFCellStyle.BORDER_THIN);
        cstyleData1.setFont(fontData);
        cstyleData1.setAlignment(HSSFCellStyle.ALIGN_LEFT);*/
        for(Map row1 : rows){
            row = sheet.createRow(index);
            //獲取map的所有需要導入到excel中數據key值
            for(int i = 0 ; i < rowkeys.length ; i++){
                HSSFCell cell = row.createCell(i);
                cell.setCellStyle(cstyleData);
                String key = rowkeys[i];
                String cellValue="";
                if(row1.get(key)!=null){
                    cellValue =row1.get(key).toString();
                }
                else{
                    cellValue="";
                }
                cell.setCellValue(cellValue);
            }
            index++;
        }

        /** ----------- 生成說明行     ------------*/
        HSSFFont fontDesc = workbook.createFont();
        HSSFCellStyle descStyle =workbook.createCellStyle();
        descStyle.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
        descStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
        descStyle.setAlignment(CellStyle.ALIGN_LEFT);
        descStyle.setVerticalAlignment(CellStyle.VERTICAL_TOP);
        fontDesc.setFontHeightInPoints((short) 9);
        descStyle.setFont(fontDesc);

        //最後行寫入描述
        /*
        sheet.addMergedRegion(new Region(index,(short)0,index,(short)(headers.length-1)));
        HSSFRow rowDesc = sheet.createRow(index);
        rowDesc.setHeight((short)1500);
        HSSFCell cellDesc = rowDesc.createCell(0);
        cellDesc.setCellStyle(descStyle);
        descStyle.setWrapText(true);
        cellDesc.setCellValue(new HSSFRichTextString(conditionsDescrip));
         */
    }
    try {
        workbook.write(out);
    } catch (IOException e) {
        e.printStackTrace();
    }

}

}

/*Action層中的方法*/
public String exportQuesByTypeAndId(){
        try {

            ExportExcelUtils<T> ex = new ExportExcelUtils<T>();
            ByteArrayOutputStream bos = new ByteArrayOutputStream();

            // 獲取查詢數據
            List<Map> rows = null;
            String questionnaireId = ServletActionContext.getRequest().getParameter("questionnaireId");
            TbInteractionQuestionnaire tbQuestionnaire=(TbInteractionQuestionnaire) questionnaireService.getDataBaseDao().load(TbInteractionQuestionnaire.class, questionnaireId);
            String type=ServletActionContext.getRequest().getParameter("type");
            rows = questionnaireService.exportQuesByTypeAndId(questionnaireId,type);
            int i=0;
            String name=tbQuestionnaire.getQuestionnaireTitle()+"_參與人員_"+DataConvertUtil.getCurrentDate();
            if(rows!=null && rows.size()>0 && rows.get(0)!=null){
            //headers 表示excel首行標題
                String[] headers =new String[rows.get(0).size()];
            //rowkeys 表示excel填充數據行對應的key
                String[] rowkeys =new String[rows.get(0).size()];
                System.out.println(rows.size());
                Iterator ita = rows.get(0).entrySet().iterator(); 
                while(ita.hasNext()){
                    /*這裏面我將數據庫查詢出的數據字段名稱
                    替換成對應中文作爲Excel每列標題，將字段
                    名稱直接作爲數據行的key，分別將標題和
                    key存放在數組中，這裏大家可以自定義
                    Excel的每列標題，key可以直接取庫中
                    字段名稱。
                    */
                    Entry entry = (Entry)ita.next();
                    headers[i]=entry.getKey().toString().replaceAll("userAccount","工號/學號").replaceAll("orgName","部門").replaceAll("persontype", "類別").replaceAll("voteFlag","參與狀態");
                    rowkeys[i]=entry.getKey().toString();
                    i++;
                }
                ex.exportExcel(name, headers, rows, 
                rowkeys,bos);
            }
            else{
                /*
                這裏當數據集爲空則傳入null,
                輸出流對象必輸傳
                */
                ex.exportExcelNoAnswerForQues(name             
                    ,null, null,null,bos);
            }
            byte[] fileBytes = bos.toByteArray();
            ByteArrayInputStream bis = new ByteArrayInputStream(fileBytes);
            bos.close();
            inputStream = bis;
            //這裏fileName指定爲文件的名稱（全局變量需要給出相應的getter,setter方法）
            fileName = new String((name + ".xls").getBytes(),"ISO-8859-1");
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            rspCode = RtnCodeConstant.RTN_CODE_UNKNOW_ERROR;
            e.printStackTrace();
        }
        return SUCCESS;
    }

//這裏是struts的配置

<action name="exportQuesByTypeAndId"
   class="queryQuertionnaireAction" 
        method="exportQuesByTypeAndId">
    <result type="stream">
        <param name="noCache">true</param>
        <param name="contentType">application/octet-stream</param>
        <param name="inputName">inputStream</param>
        <param name="contentDisposition">attachment;filename="${fileName}"</param>
        <param name="bufferSize">false</param>
    </result>
    <result      name="noSession">/jsps/login/no_session.jsp
    </result>
</action>

//下圖爲數據庫 中查詢的數據

//注：導出excel需通過location.href 的方式直接請求後臺方法，或者使用表單提交方式