Servlet 中使用POI生成Excel

使用的是poi3.13

http://mvnrepository.com/artifact/org.apache.poi/poi/3.13

import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.Iterator;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
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;

/**
 * @author yan
 * @param <T>
 * @date 2016-12-6 20:38:24
 * @version V1.0
 * @desc
 */
public class ExcelUtil<T> {

    public HSSFWorkbook exportExcel(String title, String[] headers, List<T> dataset) {

        // 声明一个工作薄
        HSSFWorkbook workbook = new HSSFWorkbook();
        // 生成一个表格
        HSSFSheet sheet = workbook.createSheet(title);
        // 设置表格默认列宽度为15个字节
        sheet.setDefaultColumnWidth((short) 15);  

        // 生成一个样式
        HSSFCellStyle style = workbook.createCellStyle();
        // 设置这些样式
        style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
        style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);

        // 生成一个字体
        HSSFFont font = workbook.createFont();
        font.setColor(HSSFColor.VIOLET.index);
        font.setFontHeightInPoints((short) 12);
        font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);

        // 把字体应用到当前的样式
        style.setFont(font);
        // 生成并设置另一个样式
        HSSFCellStyle style2 = workbook.createCellStyle();
        style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
        style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
        style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        style2.setBorderRight(HSSFCellStyle.BORDER_THIN);
        style2.setBorderTop(HSSFCellStyle.BORDER_THIN);
        style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
        // 生成另一个字体
        HSSFFont font2 = workbook.createFont();
        font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);
        // 把字体应用到当前的样式
        style2.setFont(font2);

        // 产生表格标题行
        HSSFRow row = sheet.createRow(0);
        for (short i = 0; i < headers.length; i++) {
            HSSFCell cell = row.createCell(i);
            cell.setCellStyle(style);
            HSSFRichTextString text = new HSSFRichTextString(headers[i]);
            cell.setCellValue(text);
        }

        // 遍历集合数据，产生数据行
        Iterator<T> it = dataset.iterator();
        int index = 0;

        try {

            while (it.hasNext()) {
                index++;
                row = sheet.createRow(index);
                T t = (T) it.next();

                // 利用反射，根据javabean属性的先后顺序，动态调用getXxx()方法得到属性值
                Field[] fields = t.getClass().getDeclaredFields();
                for (short i = 0; i < fields.length; i++) {
                    HSSFCell cell = row.createCell(i);
                    cell.setCellStyle(style2);
                    Field field = fields[i];
                    String fieldName = field.getName();
                    String getMethodName = "get"
                            + fieldName.substring(0, 1).toUpperCase()
                            + fieldName.substring(1);

                    Class tCls = t.getClass();

                    Method getMethod = tCls.getMethod(getMethodName, new Class[]{});

                    Object value = getMethod.invoke(t, new Object[]{});

                    //全部当做字符串来处理
                    String textValue = value.toString();

                    if (textValue != null) {
                        HSSFRichTextString richString = new HSSFRichTextString(textValue);
                        HSSFFont font3 = workbook.createFont();
                        font3.setColor(HSSFColor.BLUE.index);
                        richString.applyFont(font3);
                        cell.setCellValue(richString);
                    }
                }
            }

        } catch (NoSuchMethodException ex) {
            Logger.getLogger(NewServlet.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SecurityException ex) {
            Logger.getLogger(NewServlet.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            Logger.getLogger(NewServlet.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalArgumentException ex) {
            Logger.getLogger(NewServlet.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvocationTargetException ex) {
            Logger.getLogger(NewServlet.class.getName()).log(Level.SEVERE, null, ex);
        }

        return workbook;
    }
}

import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.codec.binary.Base64;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

/**
 *
 * @author yan
 */
public class NewServlet extends HttpServlet {

    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        response.setHeader("Connection", "close");
        response.setHeader("Content-Type", "application/vnd.ms-excel;charset=UTF-8");
        String filename = System.currentTimeMillis() + "学生信息.xls";
        filename = encodeFileName(request, filename);
        response.setHeader("Content-Disposition", "attachment;filename=" + filename);

        OutputStream out = null;

        try {
            String[] headers = { "姓名", "年龄"};
            List<Student> dataset = new ArrayList<Student>();
            dataset.add(new Student("张三张三张三张三张三张三", "20"));
            dataset.add(new Student("李四", "24"));
            dataset.add(new Student("王五王五王五王五王五王五王五王五", "2211111111111123213")); 

            ExcelUtil<Student> eu = new ExcelUtil<Student>();
            HSSFWorkbook workbook = eu.exportExcel("发票领用",headers,dataset);

            out = response.getOutputStream();
            workbook.write(out);
        } finally {
            if(out!=null){
                out.close();
            }
        }
    }

    public String encodeFileName(HttpServletRequest request, String fileName) throws UnsupportedEncodingException {
        String agent = request.getHeader("USER-AGENT");

        if (null != agent && -1 != agent.indexOf("MSIE")) {
            return URLEncoder.encode(fileName, "UTF-8");
        } else if (null != agent && -1 != agent.indexOf("Mozilla")) {
            return "=?UTF-8?B?"+ (new String(Base64.encodeBase64(fileName.getBytes("UTF-8")))) + "?=";
        } else {
            return fileName;
        }
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        processRequest(request, response);
    }
}