文件上传和下载(二)--【struts2】

一、简介

struts2在原有的上传解析器继承上做了进一步封装，更进一步简化了文件上传。

struts2默认使用的是Jakarta和Common-FileUpload的文件上传框架，因此，如果需要使用struts2的文件上传功能，则需要在web应用导入相关jar包。

二、实现原理

1、Action需要使用3个属性来封装该文件域的信息：

（1）类型为File的xxx属性封装了该文件域对应的文件内容。

（2）类型为String的xxxFileName属性封装了改文件域对应的文件的文件类型。

（3）类型为String的xxxContentType属性封装了该文件域对应的文件的类型。

2、配置struts.xml

struts.xml配置拦截器，设置允许上传类型、文件大小等信息。

3、官网例子

三、项目实践【myeclipse10】

项目目录预览

web.xml配置

<?xml version="1.0" encoding="UTF-8"?><web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">  <display-name>struts2</display-name>    <filter>        <filter-name>struts2</filter-name>        <filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>    </filter>    <filter-mapping>        <filter-name>struts2</filter-name>        <url-pattern>/*</url-pattern>    </filter-mapping>    <welcome-file-list>    <welcome-file>index.jsp</welcome-file>  </welcome-file-list></web-app>

上传action【Struts2UploadAction.java】

package com.wuhn.struts2.action;import java.io.File;import java.io.IOException;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;/** * @author wuhn * @创建时间 2015-12-09 * @功能 上传 * **/public class Struts2UploadAction extends ActionSupport {private File image; //上传的文件  private String imageFileName; //文件名称 要注意前缀要和file的变量一样private String imageContentType; //文件类型 要注意前缀要和file的变量一样    private String result;//返回信息    public File getImage() {return image;}public void setImage(File image) {this.image = image;}public String getImageFileName() {return imageFileName;}public void setImageFileName(String imageFileName) {this.imageFileName = imageFileName;}public String getImageContentType() {return imageContentType;}public void setImageContentType(String imageContentType) {this.imageContentType = imageContentType;}public String getResult() {return result;}public void setResult(String result) {this.result = result;}@Override    public String execute() throws Exception{    //设置存储路径    String path = ServletActionContext.getServletContext().getRealPath("/images");    File localFile = new File(path);    if(!localFile.exists()){    localFile.mkdir();    }    System.out.println("image:"+image);    System.out.println("imageFileName:"+imageFileName);    System.out.println("imageContentType:"+imageContentType);    System.out.println("文件是否存在："+image.exists());    //保存文件FileUtils.copyFile(image, new File(localFile, imageFileName));result = "上传成功！";            return SUCCESS;     }    }

下载action【Struts2DownloadAction.java】

package com.wuhn.struts2.action;import java.io.File;import java.io.IOException;import java.io.InputStream;import java.io.UnsupportedEncodingException;import java.net.URLEncoder;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;/** * @author wuhn * @创建时间 2015-12-09 * @功能 下载 * **/public class Struts2DownloadAction extends ActionSupport{private String inputPath;//下载路径 在struts.xml中配置private String filename;//下载文件名public String getInputPath() {return inputPath;}public void setInputPath(String inputPath) {this.inputPath = inputPath;}public String getFilename() {return filename;}public void setFilename(String filename) {this.filename = filename;}@Overridepublic String execute() throws Exception {return SUCCESS;}public InputStream getInputStream() throws IOException{String path = ServletActionContext.getServletContext().getRealPath("/images");String filepath = path + "\\" +filename;File file = new File(filepath);return FileUtils.openInputStream(file);//return ServletActionContext.getServletContext().getResourceAsStream(inputPath);}public String getDownloadFileName(){String downloadFileName = "";//中文处理try {downloadFileName = URLEncoder.encode(filename, "UTF-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}return downloadFileName;}}

批量上传【BatchStruts2UploadAction.java】

package com.wuhn.struts2.action;import java.io.File;import java.util.List;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;/** * @author wuhn * @创建时间 2015-12-10 * @功能 批量上传 * **/public class BatchStruts2UploadAction extends ActionSupport {private List<File> image; //上传的文件  private List<String> imageFileName; //文件名称 要注意前缀要和file的变量一样private List<String> imageContentType; //文件类型 要注意前缀要和file的变量一样    private String result;//返回信息public List<File> getImage() {return image;}public void setImage(List<File> image) {this.image = image;}public List<String> getImageFileName() {return imageFileName;}public void setImageFileName(List<String> imageFileName) {this.imageFileName = imageFileName;}public List<String> getImageContentType() {return imageContentType;}public void setImageContentType(List<String> imageContentType) {this.imageContentType = imageContentType;}public String getResult() {return result;}public void setResult(String result) {this.result = result;}    @Override    public String execute() throws Exception{    //设置存储路径    String path = ServletActionContext.getServletContext().getRealPath("/images");    File localFile = new File(path);    if(!localFile.exists()){    localFile.mkdir();    }    //循环保存文件    for (int i=0;i<image.size();i++) {    FileUtils.copyFile(image.get(i), new File(localFile, imageFileName.get(i)));}result = "上传成功！";            return SUCCESS;     }}

struts.xml配置

<?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>    <constant name="struts.enable.DynamicMethodInvocation" value="false" />    <constant name="struts.devMode" value="true" />    <!-- 该属性指定需要Struts2处理的请求后缀，该属性的默认值是action，即所有匹配*.action的请求都由Struts2处理。        如果用户需要指定多个请求后缀，则多个后缀之间以英文逗号（,）隔开。     -->    <constant name="struts.action.extension" value="action" />    <!-- 设置浏览器是否缓存静态内容,默认值为true(生产环境下使用),开发阶段最好关闭 -->    <constant name="struts.serve.static.browserCache" value="false" />    <!-- 当struts的配置文件修改后,系统是否自动重新加载该文件,默认值为false(生产环境下使用),开发阶段最好打开 -->    <constant name="struts.configuration.xml.reload" value="true" />    <!-- 开发模式下使用,这样可以打印出更详细的错误信息 -->    <constant name="struts.devMode" value="true" />    <!-- 默认的视图主题 -->    <constant name="struts.ui.theme" value="simple" />    <!--<constant name="struts.objectFactory" value="spring" />-->    <!--解决乱码    -->    <constant name="struts.i18n.encoding" value="UTF-8" />    <!-- 指定允许上传的文件最大字节数。默认值是2097152(2M) -->    <constant name="struts.multipart.maxSize" value="10701096"/>    <!-- 设置上传文件的临时文件夹,默认使用javax.servlet.context.tempdir    <constant name="struts.multipart.saveDir " value="d:/tmp" /> --> <!-- 国际化 app_zh_CN.properties --> <constant name="struts.custom.i18n.resources" value="app"></constant>      <package name="default" namespace="/" extends="struts-default">    <!-- 上传 --><action name="upload" class="com.wuhn.struts2.action.Struts2UploadAction"><result name="success">/jsp/01.jsp</result><result name="input">/jsp/error.jsp</result><!-- 配置拦截器限制上传文件类型及大小 --><interceptor-ref name="fileUpload"><!-- 文件过滤 --><param name="allowedTypes">image/png,image/gif,image/jpeg</param><!-- 文件大小, 以字节为单位 --><param name="maximumSize">10240000</param> </interceptor-ref><!-- 默认拦截器必须放在fileUpload之后，否则无效 --><interceptor-ref name="defaultStack"></interceptor-ref></action><!-- 批量上传 --><action name="batchUpload" class="com.wuhn.struts2.action.BatchStruts2UploadAction"><result name="success">/jsp/03.jsp</result><result name="input">/jsp/error.jsp</result><!-- 配置拦截器限制上传文件类型及大小 --><interceptor-ref name="fileUpload"><!-- 文件过滤 --><param name="allowedTypes">image/png,image/gif,image/jpeg</param><!-- 文件大小, 以字节为单位 --><param name="maximumSize">10240000</param> </interceptor-ref><!-- 默认拦截器必须放在fileUpload之后，否则无效 --><interceptor-ref name="defaultStack"></interceptor-ref></action><!-- 下载 --><action name="download" class="com.wuhn.struts2.action.Struts2DownloadAction"><!-- <param name="inputPath">images/20151026165425.png</param> --><result name="success" type="stream">     <param name="contentType">application/octet-stream</param>  <param name="inputName">inputStream</param>  <param name="contentDisposition">attachment;filename="${downloadFileName}"</param>  <param name="bufferSize">1024</param></result></action>    </package><!--     <include file="example.xml"/> --></struts>

页面

1、上传页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%@taglib uri="/struts-tags" prefix="s" %><!DOCTYPE><html>  <head>    <base href="<%=basePath%>">        <title>上传</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"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    <form action="<%=path%>/upload.action" method="post" enctype="multipart/form-data">    上传文件：<input type="file" name="image"/>    <input type="submit" value="提交"/>${result}    </form>  </body></html>

2、下载页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%@taglib uri="/struts-tags" prefix="s" %><!DOCTYPE><html>  <head>    <base href="<%=basePath%>">        <title>下载</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"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    下载文件<a href="<%=path%>/download.action?filename=20151026165425.png">文件</a>  </body></html>

3、批量上传

<%@ 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>批量上传</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"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    <form action="<%=path%>/batchUpload.action" method="post" enctype="multipart/form-data">    上传文件1：<input type="file" name="image"/>    上传文件2：<input type="file" name="image"/>    上传文件3：<input type="file" name="image"/>    <input type="submit" value="提交"/>${result}    </form>  </body></html>

这里还做了一个上传erro统一处理页面

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><%@taglib uri="/struts-tags" prefix="s" %><!DOCTYPE><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'error.jsp' starting page</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"><!--<link rel="stylesheet" type="text/css" href="styles.css">-->  </head>    <body>    错误：<s:fielderror></s:fielderror>  </body></html>

配置一个properties

四、项目代码【点击这里下载】