Struts2之上传下载和页面渲染图片功能

Struts2的上传下载是整合了commons-fileupload-1.2.2.jar这个包的功能，不过还需要commons-io-2.3.jar这个包的支持。其实上传下载功能主要是配置，下面是我的一个小例子，
可以实现上传下载，并且渲染图片到页面的效果，AbstractBaseAction这个基类代码可以翻看我之前写的博文中有贴出代码。
大概主要下面几点：
1.提交表单form的enctype属性
2.struts.xml的配置，下载要注意result的type，上传要注意拦截器的配置，这里我还配置了资源文件，利用国际化来做文件上传表单的验证功能。

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd">
<struts>
	<constant name="struts.devMode" value="true" />
	<constant name="struts.custom.i18n.resources" value="messages" />
	<constant name="struts.configuration.xml.reload" value="true" />
	<constant name="struts.enable.SlashesInActionNames" value="true" />
	<constant name="struts.ognl.allowStaticMethodAccess" value="true" />
	<constant name="struts.multipart.maxSize" value="30480000" />
	<constant name="struts.ui.theme" value="simple" />

	<package name="main" extends="struts-default">

		<default-interceptor-ref name="paramsPrepareParamsStack" />

		<action name="*-*" class="com.chou.web.PlayerAction" method="{2}">
			<interceptor-ref name="token">
				<param name="includeMethods">save</param>
			</interceptor-ref>
			<interceptor-ref name="paramsPrepareParamsStack">
				<param name="fileUpload.allowedTypes">image/bmp,image/png,image/gif,image/jpeg,image/jpg,image/x-png,image/pjpeg</param>
				<param name="fileUpload.allowedExtensions">.jpg,.gif,.jpeg,.bmp,.png</param>
				<param name="fileUpload.maximumSize">20971520</param>
			</interceptor-ref>

			<result name="input">player-load.jsp</result>
			<result name="invalid.token">player-load.jsp</result>
			<result name="success">{1}-{2}.jsp</result>
			<result name="list" type="redirect">player-list</result>
			<result name="download" type="stream">
				<param name="contentType">${fileContentType}</param>
				<param name="contentLength">${fileContentLength}</param>
				<param name="contentDisposition">attachment;filename="${fileFileName}"</param>
				<param name="inputName">fileStream</param>
				<param name="bufferSize">4096</param>
			</result>
		</action>

	</package>
</struts>

public class PlayerAction extends AbstractBaseAction<Player> {

	private static final long serialVersionUID = -3068068486865209475L;

	PlayerDao playerDao = new PlayerDao();

	/**
	 * 文件属性
	 */
	private File file;

	private String fileFileName;
	
	private InputStream fileStream;

	private String fileContentType;

	private int fileContentLength;

	public String list() throws Exception {
		return SUCCESS;
	}

	public void prepareSave() throws Exception {
		Player player = getModel();
		if (getId() != null) {
			player = playerDao.loadPlayer(getId());
		}
		setModel(player);
	}

	public String save() throws Exception {
		// System.out.println(fileContentType);
		// System.out.println(fileFileName);
		Player player = getModel();
		if (file != null) {// 新增或者修改照片操作
			FileInputStream fis = null;
			byte[] buf = new byte[(int) file.length()];
			try {
				fis = new FileInputStream(file);
				fis.read(buf);
				player.setImage(buf);
			} catch (IOException e) {
				e.printStackTrace();
				addActionError("读取上传文件失败。");
				LOG.error("读取上传文件失败。", e, new String[0]);
				return ERROR;
			} finally {
				if (fis != null) {
					try {
						fis.close();
					} catch (IOException e) {
						LOG.error("关闭FileInputStream失败。", e, new String[0]);
					}
				}
			}
		} else if (file == null && getId() != null) {// 修改操作，但是不修改照片
			player.setImage(playerDao.loadPlayer(getId()).getImage());
		}
		if (player != null) {
			player.setCreatetime(new Date());
			playerDao.saveOrUpdate(player);
			return "list";
		}
		return INPUT;
	}

	public void prepareLoad() throws Exception {
		Player player = getModel();
		if (getId() != null) {
			player = playerDao.loadPlayer(getId());
			player.setImage(null);
		} else {
			player.setBirthday(new Date());
			player.setContract("输入详细合同情况");
		}
		setModel(player);
	}

	public String load() throws Exception {
		return SUCCESS;
	}

	public void prepareDownload() throws Exception {
		Player player = getModel();
		if (getId() != null) {
			player = playerDao.loadPlayer(getId());
		}
		setModel(player);
	}

	public String download() throws Exception {
		if (getId() != null) {
			try {
				Player player = getModel();
				setFileContentType("image/jpg");
				setFileContentLength(player.getImage().length);
				setFileFileName(new String(player.getName().getBytes(),
						"iso-8859-1") + ".jpg");
				setFileStream(new ByteArrayInputStream(player.getImage()));
			} catch (Exception e) {
				LOG.error("加载文件出错。", new String[0]);
			}
		}
		return "download";
	}
        //把图片渲染到页面
	public String showImage() throws Exception {
		byte[] bigImgByte = null;
		OutputStream out = null;
		HttpServletResponse response = ServletActionContext.getResponse();
		if (getId() == null) {
			response.setHeader("Content-disposition", "attachment; filename="
					+ "no.jpg");
			response.setContentType("image/jpeg");
			out = response.getOutputStream();
			out.write(bigImgByte);
			out.flush();
			return NONE;
		}
		Player player = playerDao.loadPlayer(getId());
		if (player.getImage() == null) {
			return NONE;
		}
		bigImgByte = player.getImage();
		try {
			response.setHeader("Content-disposition", "attachment; filename="
					+ player.getName().trim().replace(" ", "") + ".jpg");
			response.setContentType("image/jpeg");
			out = response.getOutputStream();
			out.write(bigImgByte);
			out.flush();
		} catch (Exception e) {
			System.out.println("没有图片！！");
		} finally {
			try {
				if (null != out)
					out.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return NONE;
	}

	/**
	 * getter....setter
	 */

}

<body>
		<div align="center"><h1>添加球员</h1></div>
		<s:if test="hasErrors()">
			<s:fielderror/>
			<s:actionerror/>
		</s:if>
		<s:form id="sForm" action="player-save" enctype="multipart/form-data" method="post" onsubmit="return verifyUpload()">
		<s:hidden name="id" />
		<s:token/>
		<table align="center" border="1">
			<tr>
				<th>姓名</th>
				<td><s:textfield name="name" maxlength="20" required="true"/></td>
				<th>出生日期</th>
				<td>
				</td>
			</tr>
			<tr>	
				<th>身高</th>
				<td><s:textfield name="high" maxlength="5"/></td>
				<th>体重</th>
				<td><s:textfield name="weight" maxlength="5"/></td>
			</tr>
			<tr>
				<th>球队</th>
				<td><s:textfield name="team" maxlength="30"/></td>
				<th>位置</th>
				<td><s:select name="place" list="placeKinds" listKey="key" listValue="value"/></td>
			</tr>
			<tr>
				<th>号码</th>
				<td><s:textfield name="no" maxlength="2"/></td>
				<th>选秀顺位</th>
				<td><s:textfield name="draft" maxlength="30"/></td>
			</tr>
			<tr>
				<th>国籍</th>
				<td><s:textfield name="nationality" maxlength="10"/></td>
				<th>毕业学校</th>
				<td><s:textfield name="school" maxlength="50"/></td>
			</tr>
			<tr>
				<th>本季工资</th>
				<td><s:textfield name="salary" maxlength="10"/></td>
				<th>球员图片</th>
				<td>
					<s:file name="file" />
				</td>
			</tr>
			<tr>
				<td>
					<img style="cursor:pointer" alt="<s:property value="name"/>" src="<s:url action="player-showImage" ><s:param name="id"><s:property value="id"/></s:param></s:url>">
				</td>
				<th>合同情况</th>
				<td colspan="2"><s:textarea name="contract" cols="30" rows="4"/></td>
			</tr>
			<tr>
				<td colspan="4" align="center">
					<s:reset value="重置"/>&nbsp;&nbsp;&nbsp;&nbsp;
					<s:submit value="提交"/>
				</td>
			</tr>
		</table>
		</s:form>
	</body>

struts.messages.error.content.type.not.allowed=文件上传失败：你要上传的文件"{1}"文件类型不匹配
struts.messages.error.file.extension.not.allowed=只允许上传图片，请检查文件"{1}"后缀名
struts.messages.error.file.too.large=文件“{1}”大小超过所允许的上限（20M）

struts.messages.invalid.token=请不要重复提交表单
xwork.default.invalid.fieldvalue=无效的数据，请检查日期、数值类型数据的格式是否正确"{0}"