需要導出的數據是根據自定義註解，通過反射獲取的，關於自定義註解後面再做討論，目前僅梳理excel的導出

package com.thinkgem.jeesite.common.utils.excel;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
 
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.apache.poi.ss.usermodel.Cell;
 
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Comment;
import org.apache.poi.ss.usermodel.DataValidation;
import org.apache.poi.ss.usermodel.DataValidationConstraint;
import org.apache.poi.ss.usermodel.DataValidationHelper;
import org.apache.poi.ss.usermodel.Font;
 
import org.apache.poi.ss.usermodel.IndexedColors;
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.ss.util.CellRangeAddress;
import org.apache.poi.ss.util.CellRangeAddressList;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFClientAnchor;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.collect.Lists;
import com.thinkgem.jeesite.common.utils.Encodes;
import com.thinkgem.jeesite.common.utils.Reflections;
import com.thinkgem.jeesite.common.utils.excel.annotation.ExcelField;
import com.thinkgem.jeesite.modules.sys.entity.Dict;
import com.thinkgem.jeesite.modules.sys.utils.DictUtils;

/**
 * 導出Excel文件（導出“XLSX”格式，支持大數據量導出   @see org.apache.poi.ss.SpreadsheetVersion）
 * @author ThinkGem
 * @version 2013-04-21
 */
public class ExportExcel {
    
    private static Logger log = LoggerFactory.getLogger(ExportExcel.class);
            
    /**
     * 工作薄對象
     */
    private SXSSFWorkbook wb;
    
    /**
     * 工作表對象
     */
    private Sheet sheet;
    
    /**
     * 樣式列表
     */
    private Map<String, CellStyle> styles;
    
    /**
     * 當前行號
     */
    private int rownum;
    
    /**
     * 註解列表（Object[]{ ExcelField, Field/Method }）
     */
    List<Object[]> annotationList = Lists.newArrayList();
    
    /**
     * 構造函數
     * @param title 表格標題，傳“空值”，表示無標題
     * @param cls 實體對象，通過annotation.ExportField獲取標題
     */
    public ExportExcel(String title, Class<?> cls){
        this(title, cls, 1);
    }
    
    /**
     * 構造函數
     * @param title 表格標題，傳“空值”，表示無標題
     * @param cls 實體對象，通過annotation.ExportField獲取標題
     * @param type 導出類型（1:導出數據；2：導出模板）
     * @param groups 導入分組
     */
    public ExportExcel(String title, Class<?> cls, int type, int... groups){
        // Get annotation field 
        Field[] fs = cls.getDeclaredFields();
        for (Field f : fs){
            ExcelField ef = f.getAnnotation(ExcelField.class);
            if (ef != null && (ef.type()==0 || ef.type()==type)){
                if (groups!=null && groups.length>0){
                    boolean inGroup = false;
                    for (int g : groups){
                        if (inGroup){
                            break;
                        }
                        for (int efg : ef.groups()){
                            if (g == efg){
                                inGroup = true;
                                annotationList.add(new Object[]{ef, f});
                                break;
                            }
                        }
                    }
                }else{
                    annotationList.add(new Object[]{ef, f});
                }
            }
        }
        // Get annotation method
        Method[] ms = cls.getDeclaredMethods();
        for (Method m : ms){
            ExcelField ef = m.getAnnotation(ExcelField.class);
            if (ef != null && (ef.type()==0 || ef.type()==type)){
                if (groups!=null && groups.length>0){
                    boolean inGroup = false;
                    for (int g : groups){
                        if (inGroup){
                            break;
                        }
                        for (int efg : ef.groups()){
                            if (g == efg){
                                inGroup = true;
                                annotationList.add(new Object[]{ef, m});
                                break;
                            }
                        }
                    }
                }else{
                    annotationList.add(new Object[]{ef, m});
                }
            }
        }
        // Field sorting
        Collections.sort(annotationList, new Comparator<Object[]>() {
            public int compare(Object[] o1, Object[] o2) {
                return new Integer(((ExcelField)o1[0]).sort()).compareTo(
                        new Integer(((ExcelField)o2[0]).sort()));
            };
        });
        // Initialize
        List<String> headerList = Lists.newArrayList();
        for (Object[] os : annotationList){
            String t = ((ExcelField)os[0]).title();
            // 如果是導出，則去掉註釋
            if (type==1){
                String[] ss = StringUtils.split(t, "**", 2);
                if (ss.length==2){
                    t = ss[0];
                }
            }
            headerList.add(t);
        }
        initialize(title, headerList);
    }
    
    /**
     * 構造函數
     * @param title 表格標題，傳“空值”，表示無標題
     * @param headers 表頭數組
     */
    public ExportExcel(String title, String[] headers) {
        initialize(title, Lists.newArrayList(headers));
    }
    
    /**
     * 構造函數
     * @param title 表格標題，傳“空值”，表示無標題
     * @param headerList 表頭列表
     */
    public ExportExcel(String title, List<String> headerList) {
        initialize(title, headerList);
    }
    
    /**
     * 初始化函數
     * @param title 表格標題，傳“空值”，表示無標題
     * @param headerList 表頭列表
     */
    private void initialize(String title, List<String> headerList) {
        this.wb = new SXSSFWorkbook(500);
        this.sheet = wb.createSheet("Export");
        this.styles = createStyles(wb);
        // Create title
        if (StringUtils.isNotBlank(title)){
            Row titleRow = sheet.createRow(rownum++);
            titleRow.setHeightInPoints(30);
            Cell titleCell = titleRow.createCell(0);
            titleCell.setCellStyle(styles.get("title"));
            titleCell.setCellValue(title);
            sheet.addMergedRegion(new CellRangeAddress(titleRow.getRowNum(),
                    titleRow.getRowNum(), titleRow.getRowNum(), headerList.size()-1));
        }
        // Create header
        if (headerList == null){
            throw new RuntimeException("headerList not null!");
        }
        Row headerRow = sheet.createRow(rownum++);
        headerRow.setHeightInPoints(16);
        for (int i = 0; i < headerList.size(); i++) {
            Cell cell = headerRow.createCell(i);
            cell.setCellStyle(styles.get("header"));
            String[] ss = StringUtils.split(headerList.get(i), "**", 2);
            if (ss.length==2){
                cell.setCellValue(ss[0]);
                Comment comment = this.sheet.createDrawingPatriarch().createCellComment(
                        new XSSFClientAnchor(0, 0, 0, 0, (short) 3, 3, (short) 5, 6));
                comment.setString(new XSSFRichTextString(ss[1]));
                cell.setCellComment(comment);
            }else{
                cell.setCellValue(headerList.get(i));
            }
            sheet.autoSizeColumn(i);
        }
        for (int i = 0; i < headerList.size(); i++) {  
            int colWidth = sheet.getColumnWidth(i)*2;
            sheet.setColumnWidth(i, colWidth < 3000 ? 3000 : colWidth);  
        }
        log.debug("Initialize success.");
    }
    
    /**
     * 創建表格樣式
     * @param wb 工作薄對象
     * @return 樣式列表
     */
    private Map<String, CellStyle> createStyles(Workbook wb) {
        Map<String, CellStyle> styles = new HashMap<String, CellStyle>();
        
        CellStyle style = wb.createCellStyle();
        style.setAlignment(CellStyle.ALIGN_CENTER);
        style.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
        Font titleFont = wb.createFont();
        titleFont.setFontName("Arial");
        titleFont.setFontHeightInPoints((short) 16);
        titleFont.setBoldweight(Font.BOLDWEIGHT_BOLD);
        style.setFont(titleFont);
        styles.put("title", style);

        style = wb.createCellStyle();
        style.setVerticalAlignment(CellStyle.VERTICAL_CENTER);
        style.setBorderRight(CellStyle.BORDER_THIN);
        style.setRightBorderColor(IndexedColors.GREY_50_PERCENT.getIndex());
        style.setBorderLeft(CellStyle.BORDER_THIN);
        style.setLeftBorderColor(IndexedColors.GREY_50_PERCENT.getIndex());
        style.setBorderTop(CellStyle.BORDER_THIN);
        style.setTopBorderColor(IndexedColors.GREY_50_PERCENT.getIndex());
        style.setBorderBottom(CellStyle.BORDER_THIN);
        style.setBottomBorderColor(IndexedColors.GREY_50_PERCENT.getIndex());
        Font dataFont = wb.createFont();
        dataFont.setFontName("Arial");
        dataFont.setFontHeightInPoints((short) 10);
        style.setFont(dataFont);
        styles.put("data", style);
        
        style = wb.createCellStyle();
        style.cloneStyleFrom(styles.get("data"));
        style.setAlignment(CellStyle.ALIGN_LEFT);
        styles.put("data1", style);

        style = wb.createCellStyle();
        style.cloneStyleFrom(styles.get("data"));
        style.setAlignment(CellStyle.ALIGN_CENTER);
        styles.put("data2", style);

        style = wb.createCellStyle();
        style.cloneStyleFrom(styles.get("data"));
        style.setAlignment(CellStyle.ALIGN_RIGHT);
        styles.put("data3", style);
        
        style = wb.createCellStyle();
        style.cloneStyleFrom(styles.get("data"));
//        style.setWrapText(true);
        style.setAlignment(CellStyle.ALIGN_CENTER);
        style.setFillForegroundColor(IndexedColors.GREY_50_PERCENT.getIndex());
        style.setFillPattern(CellStyle.SOLID_FOREGROUND);
        Font headerFont = wb.createFont();
        headerFont.setFontName("Arial");
        headerFont.setFontHeightInPoints((short) 10);
        headerFont.setBoldweight(Font.BOLDWEIGHT_BOLD);
        headerFont.setColor(IndexedColors.WHITE.getIndex());
        style.setFont(headerFont);
        styles.put("header", style);
        
        return styles;
    }

    /**
     * 添加一行
     * @return 行對象
     */
    public Row addRow(){
        return sheet.createRow(rownum++);
    }
    

    /**
     * 添加一個單元格
     * @param row 添加的行
     * @param column 添加列號
     * @param val 添加值
     * @return 單元格對象
     */
    public Cell addCell(Row row, int column, Object val){
        return this.addCell(row, column, val, 0, Class.class);
    }
    
    /**
     * 添加一個單元格
     * @param row 添加的行
     * @param column 添加列號
     * @param val 添加值
     * @param align 對齊方式（1：靠左；2：居中；3：靠右）
     * @return 單元格對象
     */
    public Cell addCell(Row row, int column, Object val, int align, Class<?> fieldType){
        Cell cell = row.createCell(column);
        String cellFormatString = "@";
        try {
            if(val == null){
                cell.setCellValue("");
            }else if(fieldType != Class.class){
                cell.setCellValue((String)fieldType.getMethod("setValue", Object.class).invoke(null, val));
            }else{
                if(val instanceof String) {
                    cell.setCellValue((String) val);
                }else if(val instanceof Integer) {
                    cell.setCellValue((Integer) val);
                    cellFormatString = "0";
                }else if(val instanceof Long) {
                    cell.setCellValue((Long) val);
                    cellFormatString = "0";
                }else if(val instanceof Double) {
                    cell.setCellValue((Double) val);
                    cellFormatString = "0.00";
                }else if(val instanceof Float) {
                    cell.setCellValue((Float) val);
                    cellFormatString = "0.00";
                }else if(val instanceof Date) {
                    cell.setCellValue((Date) val);
                    cellFormatString = "yyyy-MM-dd HH:mm";
                }else {
                    cell.setCellValue((String)Class.forName(this.getClass().getName().replaceAll(this.getClass().getSimpleName(), 
                        "fieldtype."+val.getClass().getSimpleName()+"Type")).getMethod("setValue", Object.class).invoke(null, val));
                }
            }
            if (val != null){
                CellStyle style = styles.get("data_column_"+column);
                if (style == null){
                    style = wb.createCellStyle();
                    style.cloneStyleFrom(styles.get("data"+(align>=1&&align<=3?align:"")));
                    style.setDataFormat(wb.createDataFormat().getFormat(cellFormatString));
                    styles.put("data_column_" + column, style);
                }
                cell.setCellStyle(style);
            }
        } catch (Exception ex) {
            log.info("Set cell value ["+row.getRowNum()+","+column+"] error: " + ex.toString());
            cell.setCellValue(val.toString());
        }
        return cell;
    }

    /**
     * 添加數據（通過annotation.ExportField添加數據）
     * @return list 數據列表
     */
    public <E> ExportExcel setDataList(List<E> list){
        for (E e : list){
            int colunm = 0;
            Row row = this.addRow();
            StringBuilder sb = new StringBuilder();
            for (Object[] os : annotationList){
                ExcelField ef = (ExcelField)os[0];
                Object val = null;
                // Get entity value
                try{
                    if (StringUtils.isNotBlank(ef.value())){
                        val = Reflections.invokeGetter(e, ef.value());
                    }else{
                        if (os[1] instanceof Field){
                            val = Reflections.invokeGetter(e, ((Field)os[1]).getName());
                        }else if (os[1] instanceof Method){
                            val = Reflections.invokeMethod(e, ((Method)os[1]).getName(), new Class[] {}, new Object[] {});
                        }
                    }
                    // If is dict, get dict label
                    if (StringUtils.isNotBlank(ef.dictType())){
                        val = DictUtils.getDictLabel(val==null?"":val.toString(), ef.dictType(), "");
                        List<Dict> dicts = DictUtils.getDictList(ef.dictType());
                        String pos[] = new String[dicts.size()];
                        for(int i=0;i<dicts.size();i++){
                            Dict dict = dicts.get(i);
                            pos[i] = dict.getLabel();
                        }
                        DataValidationHelper helper = sheet.getDataValidationHelper();
                        CellRangeAddressList addressList = new CellRangeAddressList(row.getRowNum(), 255, colunm, colunm); 
                        DataValidationConstraint constraint = helper.createExplicitListConstraint(pos);   
                        DataValidation dataValidation = helper.createValidation(constraint, addressList);
                        sheet.addValidationData(dataValidation); 
                    }
                }catch(Exception ex) {
                    // Failure to ignore
                    log.info(ex.toString());
                    val = "";
                }
                this.addCell(row, colunm++, val, ef.align(), ef.fieldType());
                sb.append(val + ", ");
            }
            log.debug("Write success: ["+row.getRowNum()+"] "+sb.toString());
        }
        return this;
    }
    
    /**
     * 輸出數據流
     * @param os 輸出數據流
     */
    public ExportExcel write(OutputStream os) throws IOException{
        wb.write(os);
        return this;
    }
    
    /**
     * 輸出到客戶端
     * @param fileName 輸出文件名
     */
    public ExportExcel write(HttpServletResponse response, String fileName) throws IOException{
        response.reset();
        response.setContentType("application/octet-stream; charset=utf-8");
        response.setHeader("Content-Disposition", "attachment; filename="+Encodes.urlEncode(fileName));
        if(fileName.contains("日誌數據")){
            Cookie status = new Cookie("exportStatusLog","success");
            status.setPath("/");
            status.setMaxAge(6000000);
            response.addCookie(status);
        }
        if(fileName.contains("用戶數據")){
            Cookie statusUser = new Cookie("exportStatusUsers","success");
            //statusUser.setPath("/");
            statusUser.setMaxAge(6000000);
            response.addCookie(statusUser);
        }
        write(response.getOutputStream());
        return this;
    }
    
    /**
     * 輸出到文件
     * @param fileName 輸出文件名
     */
    public ExportExcel writeFile(String name) throws FileNotFoundException, IOException{
        FileOutputStream os = new FileOutputStream(name);
        this.write(os);
        return this;
    }
    
    /**
     * 根據路徑輸出文件
     * @param path
     * @param name
     * @return
     * @throws FileNotFoundException
     * @throws IOException
     */
    public ExportExcel writeFile(String path ,String name) throws FileNotFoundException, IOException{
        FileOutputStream os = new FileOutputStream(new File(path+File.separator+name));
        this.write(os);
        return this;
    }
    
    /**
     * 清理臨時文件
     */
    public ExportExcel dispose(){
        wb.dispose();
        return this;
    }

}

項目中Excel表的導出總結