Struts2导出Excel

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1.首先是演示工程概览

2.struts.xml

<struts><package name="Export" extends="struts-default"> <action name="listArticles" class="articleAction" method="listArticles"> <result name="success">/articleList.jsp</result> </action> <action name="exportArticles" class="articleAction" method="exportArticles"> <result name="success" type="stream">  <param name="contentType">application/vnd.ms-excel</param> <param name="contentDisposition">attachment;filename="${downloadFileName}"</param><param name="inputName">downloadFile</param> </result> </action> </package></struts>

浏览器输入http://localhost:8080/listArticles.action查询所有文章，返回articleList.jsp页。

3.articleList.jsp

<body> <a href="exportArticles.action">导出Excel</a> <table class="datalist"> <caption>文章列表</caption> <thead> <tr> <th>#</th> <th>类型</th> <th>标题</th> <th>内容</th> <th>作者</th> <th>创建时间</th> <th>状态</th> </tr> </thead> <tbody> <c:forEach var="article" items="${articleList}" varStatus="li"> <tr> <td>${li.index+1}</td> <td>${article.type}</td> <td>${article.title}</td> <td>${fn:substring(article.content,0,20)}</td> <td>${article.auther}</td> <td>${article.createTime}</td> <td>${article.status}</td> </tr> </c:forEach> </tbody> </table> </body>

点击链接“导出Excel”访问ArticleAction.java处理器类的exportArticle()方法。

4.ArticleAction.java

public class ArticleAction extends ActionSupport {private ArticleService articleService;private List<Article> articleList;private String downloadFileName = "文章列表.xls";public String listArticles() throws Exception{articleList = articleService.listArticles();return SUCCESS;}public String getDownloadFileName() throws UnsupportedEncodingException{return new String(downloadFileName.getBytes(),"ISO-8859-1");}public InputStream getDownloadFile() throws Exception{return articleService.getInputStream();}public String exportArticles() throws Exception{return SUCCESS;}}

根据<action name="exportArticles"/>的配置，返回的输入流将从ArticleAction.java的getDownloadFile()负责得到。

getDownloadFile()方法调用了service层。

这里我直接把要导出的文件名定义在属性上了，开发中自己要根据业务去setDownloadFileName()。

5.ArticleService.java

public interface ArticleService {/** * 查询所有文章 * @return Article实例集合 */public List<Article> listArticles();/** * 获取输入流 */public InputStream getInputStream() throws IOException;}

6.ArticleServiceImpl.java

public class ArticleServiceImpl implements ArticleService {private ArticleDao articleDao;public List<Article> listArticles() {return articleDao.listArticles();}public InputStream getInputStream() throws FileNotFoundException,IOException {//下面都是Apache Poi的操作了HSSFWorkbook wb = new HSSFWorkbook();HSSFSheet sheet_0 = wb.createSheet();HSSFRow row_0 = sheet_0.createRow(0);HSSFCell cell_0_0 = row_0.createCell(0);cell_0_0.setCellValue("#");HSSFCell cell_0_1 = row_0.createCell(1);cell_0_1.setCellValue("类型");HSSFCell cell_0_2 = row_0.createCell(2);cell_0_2.setCellValue("标题");HSSFCell cell_0_3 = row_0.createCell(3);cell_0_3.setCellValue("内容");HSSFCell cell_0_4 = row_0.createCell(4);cell_0_4.setCellValue("作者");HSSFCell cell_0_5 = row_0.createCell(5);cell_0_5.setCellValue("创建时间");HSSFCell cell_0_6 = row_0.createCell(6);cell_0_6.setCellValue("状态");//填充数据List<Article> articleList = this.listArticles();for(int i=0;i<articleList.size();i++){HSSFRow row = sheet_0.createRow(i+1);HSSFCell cell_0 = row.createCell(0);cell_0.setCellValue(i+1);HSSFCell cell_1 = row.createCell(1);cell_1.setCellValue(articleList.get(i).getType());HSSFCell cell_2 = row.createCell(2);cell_2.setCellValue(articleList.get(i).getTitle());HSSFCell cell_3 = row.createCell(3);cell_3.setCellValue(articleList.get(i).getContent().substring(0,20));HSSFCell cell_4 = row.createCell(4);cell_4.setCellValue(articleList.get(i).getAuther());HSSFCell cell_5 = row.createCell(5);HSSFCellStyle style = wb.createCellStyle();style.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));cell_5.setCellStyle(style);cell_5.setCellValue(articleList.get(i).getCreateTime());HSSFCell cell_6 = row.createCell(6);cell_6.setCellValue(articleList.get(i).getStatus());}//将HSSFWorkbook对象输出到字节数组输出流ByteArrayOutputStream os = new ByteArrayOutputStream();wb.write(os);os.close();//构造字节数字输入流返回InputStream is = new ByteArrayInputStream(os.toByteArray());return is;}public ArticleDao getArticleDao() {return articleDao;}public void setArticleDao(ArticleDao articleDao) {this.articleDao = articleDao;}}

这里使用了ByteArrayOutputStream和ByteArrayInputStream，直接在内存中返回字节数组输入流，好处是不产生服务器的临时文件。

原先我使用FileOutputStream和FileInputStream来处理，还得开启线程延迟删除临时文件，考虑到这期间内服务器有可能关闭，所以又要写Servlet或者服务器启动定时任务来删除此类文件。颇为麻烦。

7.ArticleDao.java

public class ArticleDao extends HibernateDaoSupport {@SuppressWarnings("unchecked")public List<Article> listArticles() {return (List<Article>)this.getHibernateTemplate().find("from Article a order by a.articleID");}}

8.applicationContext.xml

用了spring的自动装配<beans ... default-autowire="byName"/>，

这里略去dataSource、sessionFactory等配置。

9.web.xml

<context-param><param-name>contextConfigLocation</param-name><param-value>classpath:conf/spring/applicationContext.xml</param-value></context-param><listener><listener-class>org.springframework.web.context.ContextLoaderListener</listener-class></listener><filter><filter-name>struts2</filter-name><filter-class>org.apache.struts2.dispatcher.FilterDispatcher</filter-class></filter><filter-mapping><filter-name>struts2</filter-name><url-pattern>/*</url-pattern></filter-mapping>

最终效果：