【Struts】文件的上传和下载

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文件的上传

上传表单:

表单属性:enctype="multipart/form-data"

提交类型:method = "post"

输入属性: type="file"

文件上传在struts中使用文件上传拦截器上传文件

<interceptorname="fileUpload" class="org.apache.struts2.interceptor.FileUploadInterceptor"/>

Struts的默认提交大小为2M

下面我们就来实现一个文件上传的小案例

文件结构图如下:

首先在upload.jsp中写一个上传表单

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">    <title>文件上传页面</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page">  </head>  <body>  <form action="${pageContext.request.contextPath }/uploadAction" method="post" enctype="multipart/form-data">  用户名:<input type="text" name="userName"><br/><br/>  文件:<input type="file" name="file1"><br/><br/>  <input type="submit" value="上传">  </form>  </body></html>

配置对应的upload.xml文件，拦截请求,同时配置错误视图input,转发到/uploadPage/error.jsp中

<?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><package name="uploads" extends="struts-default"><!-- 注意： action 的名称不能用关键字"fileUpload" --><action name="uploadAction" class="cn.qblank.upload.UploadAction"><!-- 限制运行上传的文件类型 --><interceptor-ref name="defaultStack"><!-- 限制运行文件的扩展名 --><param name="fileUpload.allowedExtensions">txt,jpg,jar,rar,exe</param><!-- 限制运行的类型   【与上面同时使用，取交集】--><!-- <param name="fileUpload.allowedTypes">text/plain</param> --></interceptor-ref><result name="success" type="redirect">/down_list</result><!-- 配置错误视图 --><result name="input">/uploadPage/error.jsp</result></action><action name="down_*" class="cn.qblank.upload.DownloadAction" method="{1}"><result name="list">/uploadPage/list.jsp</result><!-- 下载 --><result name="download" type="stream"><!-- 运行下载的文件的类型:指定为所有的二进制文件类型 --><param name="contentType">application/octet-stream</param><!-- 对应的是Action中属性： 返回流的属性【其实就是getAttrInputStream()】 --><param name="inputName">attrInputStream</param><!-- 下载头，包括：浏览器显示的文件名 --><param name="contentDisposition">attachment;filename=${downFileName}</param><!-- 缓冲区大小设置 --><param name="bufferSize">1024</param></result></action></package></struts>

配置struts常量constant.xml,在这里我们可以对编码、访问后缀、上传文件大小等动作进行限制

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN""http://struts.apache.org/dtds/struts-2.3.dtd"><struts><!-- 一、全局配置 --><!-- 0. 请求数据编码 --> <constant name="struts.i18n.encoding" value="UTF-8"/><!-- 1. 修改Struts默认的访问后缀 --><constant name="struts.action.extension" value="action,do,"></constant><!-- 2. 修改xml自动重新加载 --><constant name="struts.configuration.xml.reload" value="true"/><!-- 3. 开启动态方法调用 (默认不开启)--><constant name="struts.enable.DynamicMethodInvocation" value="true"/><!-- 4. 修改上传文件的最大大小为300M --><constant name="struts.multipart.maxSize" value="314572800"/></struts>

写一个UploadAction对上传的文件进行处理

package cn.qblank.upload;import java.io.File;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class UploadAction extends ActionSupport{//文件private File file1;//文件名private String file1FileName;//文件类型private String file1ContentType;//配置setterpublic void setFile1(File file1) {this.file1 = file1;}public void setFile1FileName(String file1FileName) {this.file1FileName = file1FileName;}public void setFile1ContentType(String file1ContentType) {this.file1ContentType = file1ContentType;}@Overridepublic String execute() throws Exception {//获取上传路径uploadString path = ServletActionContext.getServletContext().getRealPath("/upload");//创建目标文件对象File destFile = new File(path, file1FileName);//把上传的文件拷贝到目标文件中FileUtils.copyFile(file1, destFile);System.out.println("文件类型:" + file1ContentType);return SUCCESS;}}

根据上面的upload.xml的配置，提交成功后会进入/down_list这个路径,于是我们在类DownloadAction中写一个list方法用于将提交的文件存储到域中

/** * 列出所有上传的文件 * @return * @throws Exception */public String list() throws Exception {//获取路径String path = ServletActionContext.getServletContext().getRealPath("/upload");//新建一个目录对象File file = new File(path);String[] fileNames = file.list();//保存到域中ActionContext context = ActionContext.getContext();//得到代表request的MapMap<String,Object> request = (Map<String, Object>) context.get("request");request.put("fileNames", fileNames);return "list";}

最后返回一个list标志，然后根据upload.xml中的配置，转发到/uploadPage/list.jsp，于是我们就可以写一个list.jsp界面用于显示上传的文件

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%@taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">    <title>列表</title><meta http-equiv="pragma" content="no-cache"><meta http-equiv="cache-control" content="no-cache"><meta http-equiv="expires" content="0">    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"><meta http-equiv="description" content="This is my page"><style>fieldset{width:400px}table{}</style>  </head>  <body>  <!-- 从request域中取出数据 -->  <fieldset>  <legend>文件列表</legend>  <table border="1">  <tr>  <th>序号</th>  <th>文件名</th>  <th>操作</th>  </tr>  <c:forEach varStatus="sc" var="fileName" items="${requestScope.fileNames }">  <tr>  <td>${sc.count}</td>  <td>${fileName}</td>  <td>  <!-- 构建一个url -->  <c:url value="down_down" var="url">  <c:param name="fileName" value="${fileName }"></c:param>  </c:url>  <a href="${url}">下载</a>  </td>  </tr>  </c:forEach>  </table>  </fieldset>  </body></html>

不要忘记在struts.xml中添加这些upload.xml文件

<?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><!-- 总配置文件 负责引入各个子配置文件 --><!-- 常量 --><include file="constant.xml"></include><include file="cn/qblank/excute/config.xml"></include><!-- 类型转换 --><include file="cn/qblank/type/type.xml"></include><!-- 文件上传 --><include file="cn/qblank/upload/upload.xml"></include></struts>

结果如下:

文件下载:

前面的list.jsp中已经将文件下载的地址获取到了，接下来就可以在DownloadAction中进行下载的操作

/** * 下载 *///1.获取将要下载的文件的文件名private String fileName;public void setFileName(String fileName) {try {//get方式提交 处理中文乱码fileName = new String(fileName.getBytes("ISO8859-1"),"UTF-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}this.fileName = fileName;}//2.在struts.xml中配置返回streampublic String down() throws Exception {return "download";}//3.返回文件流public InputStream getAttrInputStream(){return ServletActionContext.getServletContext().getResourceAsStream("/upload/" + fileName);}//4.使下载文件的名字为显示的中文名  与upload.xml中的downFileName相对应public String getDownFileName(){try {//进行中文编码fileName = URLEncoder.encode(fileName,"UTF-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}return fileName;}

值得注意的是这个和upload.xml中的配置是对应的,这些配置可以在api中找到

<action name="down_*" class="cn.qblank.upload.DownloadAction" method="{1}"><result name="list">/uploadPage/list.jsp</result><!-- 下载 --><result name="download" type="stream"><!-- 运行下载的文件的类型:指定为所有的二进制文件类型 --><param name="contentType">application/octet-stream</param><!-- 对应的是Action中属性： 返回流的属性【其实就是getAttrInputStream()】 --><param name="inputName">attrInputStream</param><!-- 下载头，包括：浏览器显示的文件名 --><param name="contentDisposition">attachment;filename=${downFileName}</param><!-- 缓冲区大小设置 --><param name="bufferSize">1024</param></result></action>

这样，文件下载的也完成了

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