利用POI生成Excel并通过Servlet下载示例

package com.ljz;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

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

public class downloadExcelServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	public downloadExcelServlet() {
		super();
	}

	public void destroy() {
		super.destroy();
	}

	private InputStream getInputStream() {
		HSSFWorkbook wb = new HSSFWorkbook();
		HSSFSheet sheet = wb.createSheet("sheet1");

		HSSFRow row = sheet.createRow(0);

		HSSFCell cell = row.createCell((short) 0);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("序号");

		cell = row.createCell((short) 1);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("姓");

		cell = row.createCell((short) 2);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("名");

		cell = row.createCell((short) 3);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("年龄");

		//创建一行记录
		row = sheet.createRow(1);

		cell = row.createCell((short) 0);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("1");

		cell = row.createCell((short) 1);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("刘");

		cell = row.createCell((short) 2);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("继忠");

		cell = row.createCell((short) 3);
		cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		cell.setCellValue("25");

		// List<User> list = this.findAll();
		//
		// for (int i = 0; i < list.size(); ++i)
		// {
		// User user = list.get(i);
		//
		// row = sheet.createRow(i + 1);
		//
		// cell = row.createCell((short) 0);
		// cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		// cell.setCellValue(i + 1);
		//
		// cell = row.createCell((short) 1);
		// cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		// cell.setCellValue(user.getFirstname());
		//
		// cell = row.createCell((short) 2);
		// cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		// cell.setCellValue(user.getLastname());
		//
		// cell = row.createCell((short) 3);
		// cell.setEncoding(HSSFCell.ENCODING_UTF_16);
		// cell.setCellValue(user.getAge());
		// }

		ByteArrayOutputStream os = new ByteArrayOutputStream();

		try {
			wb.write(os);
		} catch (IOException e) {
			e.printStackTrace();
		}

		byte[] content = os.toByteArray();
		InputStream is = new ByteArrayInputStream(content);
		return is;
	}

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		response.reset();
		response.setContentType("application/vnd.ms-excel;charset=utf-8");
		response.setHeader("Content-Disposition", "attachment;filename="
				+ new String("系统日志.xls".getBytes(), "iso-8859-1"));

		ServletOutputStream out = response.getOutputStream();

		BufferedInputStream bis = null;
		BufferedOutputStream bos = null;

		try {

			bis = new BufferedInputStream(this.getInputStream());
			bos = new BufferedOutputStream(out);

			byte[] buff = new byte[2048];
			int bytesRead;

			// Simple read/write loop.
			while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
				bos.write(buff, 0, bytesRead);
			}

		} catch (final IOException e) {
			System.out.println("IOException.");
			throw e;
		} finally {
			if (bis != null)
				bis.close();
			if (bos != null)
				bos.close();
		}
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

	public void init() throws ServletException {
		// Put your code here
	}

}