Struts2 多文件上传、限制文件大小、更改错误提示--文件下载

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好记性不如赖笔头…………

1、导入须要使用的jar包

这里写图片描述

2、创建jsp文件，代码如下

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><!--导入Struts2标签--><%@ taglib uri="/struts-tags" prefix="s" %><%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</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>  <h1>文件上传</h1>    <s:form action="fileUpload.action" enctype="multipart/form-data">        <s:file name="fileName" label="文件1"></s:file>        <s:file name="fileName" label="文件2"></s:file>         <s:submit value="上传"></s:submit>    </s:form>    <hr/>    <h1>文件下载</h1>    <a href="${pageContext.request.contextPath }/fileDownload.action">下载图片</a>  </body></html>

3、创建FileUploadAction类,并实现ActionSupport，具体代码如下：

package com.ckinghan.web.action;import java.io.File;import java.io.IOException;import java.util.UUID;import javax.servlet.ServletContext;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class FileUploadAction extends ActionSupport {    /**     * 支持序列化     */    private static final long serialVersionUID = 1L;    //上传文件数组    private File[] fileName;    //上传文件 的文件名    private String[] fileNameFileName;    //上传文件的MIME类型    private String[] fileNameContentType;    public File[] getFileName() {        return fileName;    }    public void setFileName(File[] fileName) {        this.fileName = fileName;    }    public String[] getFileNameFileName() {        return fileNameFileName;    }    public void setFileNameFileName(String[] fileNameFileName) {        this.fileNameFileName = fileNameFileName;    }    public String[] getFileNameContentType() {        return fileNameContentType;    }    public void setFileNameContentType(String[] fileNameContentType) {        this.fileNameContentType = fileNameContentType;    }    public String fileUpload(){        //如果上传文件为空，则直接结束        if(fileName == null || fileName.length == 0){            return null;        }        //获取ServletContext         ServletContext context = ServletActionContext.getServletContext();        //通过ServletContext 获取目录的真实路径，定位路径为：项目目录下，与WEB-INF同级，可以自由更改        String fileUrl = context.getRealPath("files");        //创建文件，如果文件夹不存在，则创建        File file = new File(fileUrl);        if(!file.exists()){            file.mkdirs();        }        //将文件复制到指定路径 下，会留下缓存文件，不建议使用        /**        try {            for (int i = 0; i < fileName.length; i++) {                FileUtils.copyFile(fileName[i],new File(file, UUID.randomUUID().toString()+fileNameFileName[i].substring(fileNameFileName[i].lastIndexOf("."), fileNameFileName[i].length())) );            }        } catch (IOException e) {            e.printStackTrace();            return null;        }        */        //将文件循环剪贴到指定位置并重命名，不会有缓存文件留下        for(int i = 0; i <fileName.length;i++){            fileName[i].renameTo(new File(file, UUID.randomUUID().toString()+fileNameFileName[i].substring(fileNameFileName[i].lastIndexOf("."), fileNameFileName[i].length())));        }        return null;    }}

4、创建文件下载 FileDownloadAction，继承ActionSupport类，具体内容如下：

package com.ckinghan.web.action;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.InputStream;import org.apache.struts2.ServletActionContext;import com.opensymphony.xwork2.ActionSupport;public class FileDownloadAction extends ActionSupport {    //注意：此处命名不能使用in，会出问题    private InputStream inputStream;    private String fileName;    public InputStream getInputStream() {        return inputStream;    }    public void setInputStream(InputStream inputStream) {        this.inputStream = inputStream;    }    public void setFileName(String fileName) {        this.fileName = fileName;    }    public InputStream getInputStream() {        return inputStream;    }    public String fileDownload() throws FileNotFoundException{        //获取图片路径        String fileUrl = ServletActionContext.getServletContext().getRealPath("/files/33e765f4-cb37-4d3a-b9ae-b09240fc6519.jpg");        //初始化流        inputStream = new FileInputStream(fileUrl);        fileName = "下载的相片.png";        return SUCCESS;    }}

5、创建替换错误提示的FileUploadAction-messages.properties文件，与FileUploadAction文件处理于同一目录下，具体内容如下：

struts.messages.error.content.type.not.allowed=\u4E0A\u4F20\u6587\u4EF6\u4EC5\u652F\u6301\u56FE\u7247\u683C\u5F0F\:struts.messages.error.file.extension.not.allowed=\u4EC5\u652F\u6301\u4EE5\u4E0B\u6269\u5C55\u540D\u6587\u4EF6\u7684\u4E0A\u4F20\uFF1Apng,jpeg,pjpeg,gif,bmp,jpg

效果图片如下：

这里写图片描述

此文件中替换内容的原始文件路径为：struts2-core-2.3.15.3.jar包下的org/apache/struts2/struts-messages.properties，文件的具体内容如下，可以参考将所有的错误替换为中文提示：

## $Id: struts-messages.properties 1379458 2012-08-31 14:06:00Z lukaszlenart $## Licensed to the Apache Software Foundation (ASF) under one# or more contributor license agreements.  See the NOTICE file# distributed with this work for additional information# regarding copyright ownership.  The ASF licenses this file# to you under the Apache License, Version 2.0 (the# "License"); you may not use this file except in compliance# with the License.  You may obtain a copy of the License at##  http://www.apache.org/licenses/LICENSE-2.0## Unless required by applicable law or agreed to in writing,# software distributed under the License is distributed on an# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY# KIND, either express or implied.  See the License for the# specific language governing permissions and limitations# under the License.#struts.messages.invalid.token=The form has already been processed or no token was supplied, please try again.struts.internal.invalid.token=Form token {0} does not match the session token {1}.struts.messages.bypass.request=Bypassing {0}/{1}struts.messages.current.file=File {0} {1} {2} {3}struts.messages.invalid.file=Could not find a Filename for {0}. Verify that a valid file was submitted.struts.messages.invalid.content.type=Could not find a Content-Type for {0}. Verify that a valid file was submitted.struts.messages.removing.file=Removing file {0} {1}struts.messages.error.uploading=Error uploading: {0}struts.messages.error.file.too.large=The file is to large to be uploaded: {0} "{1}" "{2}" {3}struts.messages.error.content.type.not.allowed=Content-Type not allowed: {0} "{1}" "{2}" {3}struts.messages.error.file.extension.not.allowed=File extension not allowed: {0} "{1}" "{2}" {3}# dedicated messages used to handle various problems with file upload - check {@link JakartaMultiPartRequest#parse(HttpServletRequest, String)}struts.messages.upload.error.SizeLimitExceededException=Request exceeded allowed size limit! Max size allowed is: {0} but request was: {1}!struts.messages.upload.error.IOException=Error uploading: {0}!devmode.notification=Developer Notification (set struts.devMode to false to disable this message):\n{0}struts.exception.missing-package-action.with-context = There is no Action mapped for namespace [{0}] and action name [{1}] associated with context path [{2}].

6、创建Struts.xml配置文件在src目录下，具体配置信息如下：

<?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>    <!-- 开启调试模式 -->    <constant name="struts.devMode" value="true"/>    <!-- 限制上传文件的大小,默认最大上传2M，这里改为了5M-->    <constant name="struts.multipart.maxSize" value="5242880"/>    <!-- 错误提示替换为中文，原配置文件路径为：struts2-core-2.3.15.3.jar/org/apache/struts2/struts-messages.properties -->    <constant name="struts.custom.i18n.resources" value="com.ckinghan.web.action.FileUploadAction-messages"/>    <!-- 开启OGNL的静态方法调用  -->    <constant name="struts.ognl.allowStaticMethodAccess" value="true"/>    <package name="fileUpload" extends="struts-default">        <action name="fileUpload" class="com.ckinghan.web.action.FileUploadAction" method="fileUpload">            <!-- 拦截器  -->            <interceptor-ref name="defaultStack">                <!-- 注入可以上传的文件类型                 <param name="fileUpload.allowedTypes">image/bmp,image/png,image/gif,image/jpeg,image/jpg</param>-->                <!-- 注入上传文件的扩展名-->                <param name="fileUpload.allowedExtensions">.png,.jpeg,.pjpeg,.gif,.bmp,.jpg</param>            </interceptor-ref>            <result name="input" >/index.jsp</result>        </action>        <!-- 图片下载 -->        <action name="fileDownload" class="com.ckinghan.web.action.FileDownloadAction" method="fileDownload">            <!-- 返回的类型为stream流 ，下面注入参数的java类为：Struts2-core-2.3.15.3.jar包下的org.apache.struts2.dispatcher.StreamResult-->            <result type="stream">                <!-- 注入返回的表头：contentType =application/x-download  -->                <param name="contentType">application/x-download</param>                <!-- 注入参数contentDisposition，返回的类型为附件下载，使用OGNL将程序给定的文件名写入命名给图片,使用URLEncoder防止中文乱码 -->                <param name="contentDisposition">attachment;filename=${@java.net.URLEncoder@encode(fileName,"UTF-8")}</param>                <!-- 将指定的动作类中的inputStream注入到inputName中，实现下载 -->                <param name="inputName">inputStream</param>            </result>        </action>    </package></struts>

配置完成，将项目启动，访问效果如下：

这里写图片描述

上传两张图片效果如下：

这里写图片描述

测试其它类型的文件上传提示，效果如下：

这里写图片描述

如果文件上传的大小超过了5M，会直接返回到上传页面。

访问下载效果图：

这里写图片描述

注意：下载的前提是，在项目目录下，有files文件夹，并有33e765f4-cb37-4d3a-b9ae-b09240fc6519.jpg图片，否则会报找不到文件错误

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