上传图片并保存到数据库
<filter> <filter-name>Seam Filter</filter-name> <filter-class>org.jboss.seam.servlet.SeamFilter</filter-class> </filter> <filter-mapping> <filter-name>Seam Filter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
s:fileUpload 标签主要属性:
- data: 需绑定一个byte[] 数组,用来接收上传的二进制数据.
- fileName: 上传文件的文件名
- accept: 允许上传的文件类型,可取 "images/png", "images/jpg".
<h:form enctype="multipart/form-data" id="upload-form"> <s:fileUpload data="#{memberHome.instance.avator}" fileName="#{memberHome.fileName}" /> <h:commandButton value="上传照片" action="#{memberHome.update()}" styleClass="btn btn-primary btn-small"> </h:commandButton> </h:form>
这里 avator 是一个byte[]数组,fileName是一个String对象. 注意必须在form中使用 "multipart/form-data" 的编码类型.
从数据库中读出图片并在页面中显示
private DataSource getDS() throws NamingException { Context context = new InitialContext(); return (DataSource) context.lookup("zhiduiDatasource"); }
lookup()中要传递你要查询的对象的名称,即在persistence.xml中<jta-data-source>节点所声明的数据源.有关JNDI的详细说明,参见Oracle官方指南: http://docs.oracle.com/javase/7/docs/technotes/guides/jndi/
private void getImageByte() { DataSource ds = null; Connection conn = null; try { ds = getDS(); conn = ds.getConnection(); Statement stat = conn.createStatement(); ResultSet res = stat.executeQuery("select * from member where id='" + memberId + "'"); while(res.next()) { imageByte = res.getBytes("avator_file"); } } catch(SQLException ex) { ex.printStackTrace(); } catch(NamingException ex) { ex.printStackTrace(); } finally { try { conn.close(); } catch(SQLException ex) { ex.printStackTrace(); } } }
最后在doGet()方法中将读出的byte[]数据返回:
@Override protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String parm = req.getParameter("memberId"); memberId = Integer.parseInt(parm); getImageByte(); resp.getOutputStream().write(imageByte, 0, imageByte.length); }
别忘了在web.xml中声明你的ImageServer并配置URL映射:
<servlet> <servlet-name>Image Servlet</servlet-name> <servlet-class>cn.edu.sudt.zhidui.servlet.ImageServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>Image Servlet</servlet-name> <url-pattern>*.showimg</url-pattern> </servlet-mapping>
这时使用<img>标签就能成功地将图片显示到页面中了.
<img src="asd.showimg?memberId=#{memberHome.instance.id}" />