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;
}

@Override
public 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】