POI完成Excel的导出

1.在index.xml编写代码

<a href="exportExcel">导出Excel</a><br>

 2.在struts.xml配置

<struts>
	<package name="team" extends="struts-default" namespace="/">
		<!--导出Excel-->
		<action name="exportExcel" class="com.iteye.action.TestAction"
			method="excelExport">
			<result type="stream">
				<param name="contentType">application/vnd.ms-excel;charset=utf8</param>
				<param name="inputName">excelExportStream</param>
				<param name="contentDisposition">attachment;filename="student.xls"</param>
			</result>
		</action>
	</package>
</struts>

3.在Action完成Excel导入

public class TestAction extends ActionSupport {

	/**
	 * 导出Excel	
	 */
	public String excelExport(){
		return SUCCESS;
	}
	//返回streamResult需要的输入流类型
	public InputStream getExcelExportStream() throws Exception {

		FileDao fileDao = new FileDao();
		// 工作簿
		HSSFWorkbook book = new HSSFWorkbook();
		// 获取工作簿的单元
		HSSFSheet sheet = book.createSheet();
		// 行后在对应的列
		HSSFRow row = sheet.createRow(0);
		HSSFCell cellold = row.createCell(0);
		HSSFCell cellnew = row.createCell(1);
		HSSFCell cellpath = row.createCell(2);
		// 单元格-表头
		cellold.setCellValue("姓名");
		cellnew.setCellValue("性别");
		cellpath.setCellValue("年龄");
		// 获取实体集合
		int i = 1;
		Iterator it = fileDao.findAll().iterator();
		while (it.hasNext()) {
			TImage t = (TImage) it.next();
			// 行后在对应的列
			HSSFRow rowa = sheet.createRow(i);
			HSSFCell cellolda = rowa.createCell(0);
			HSSFCell cellnewa = rowa.createCell(1);
			HSSFCell cellpatha = rowa.createCell(2);
			// 单元格-表头
			cellolda.setCellValue(t.getOldname());
			cellnewa.setCellValue(t.getNewname());
			cellpatha.setCellValue(t.getPathimage());
			i++;
		}	
		
		// 输出流
		ByteArrayOutputStream by = new ByteArrayOutputStream();		
		book.write(by);
		return new ByteArrayInputStream(by.toByteArray());
	}
}