先谈一谈struts2实现文件的上传和下载实例实现的原理:
Struts 2是通过Commons FileUpload文件上传。
Commons FileUpload通过将HTTP的数据保存到临时文件夹,然后Struts使用fileUpload拦截器将文件绑定到Action的实例中。从而我们就能够以本地文件方式的操作浏览器上传的文件。
具体实现:
一、创建index.jsp页面
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< body > < s:form action = "upload" method = "post" theme = "simple" enctype = "multipart/form-data" > < table align = "center" width = "50%" border = "1" > < tr > < td >选择上传文件</ td > < td id = "more" > < s:file name = "file" ></ s:file > < input type = "button" value = "Add More.." onclick = "addMore()" > </ td > </ tr > < tr > < td >< s:submit type = "button" value = "submit" onclick = "return checkf()" /></ td > < td >< s:reset value = "reset " ></ s:reset ></ td > </ tr > </ table > < table align = "center" width = "50%" border = "1" > < tr > < td >测试.txt</ td > < td > < a href="<s:url value = 'download.action' >< s:param name = 'fileName' >测试.txt</ s:param > </ s:url >">下载</ a > </ td > </ tr > </ table > </ s:form > </ body > |
创建result.jsp页面
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< body > < s:form > < div style = "border:1px solid black" >成功上传的文件:< br > < ul style = "list-style-type:decimal" > < s:iterator value = "#request.fileName" id = "file" status = "status" > < li >< s:property /> </ li > </ s:iterator > </ ul > </ div > </ s:form > </ body > |
当然别忘了在每个页面上都添加上struts2 标签引用<%@taglib prefix="s" uri="/struts-tags" %>
二、创建updown.js文件,在index.jsp中引用
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function checkf(){ var files = document.getElementsByName( "file" ); if (files[ 0 ].value.length!= 0 ){ return true ; } else { alert( "请选择文件" ); return false ; } } function addMore() { var td = document.getElementById( "more" ); var br = document.createElement( "br" ); var input = document.createElement( "input" ); var button = document.createElement( "input" ); input.type = "file" ; input.name = "file" ; button.type = "button" ; button.value = "Remove" ; button.onclick = function() { td.removeChild(br); td.removeChild(input); td.removeChild(button); } td.appendChild(br); td.appendChild(input); td.appendChild(button); } |
三、创建upDownloadAction.java
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package com.action; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.io.UnsupportedEncodingException; import java.util.List; import javax.servlet.http.HttpServletRequest; import com.opensymphony.xwork2.ActionSupport; import org.apache.struts2.ServletActionContext; public class UpDownloadAction extends ActionSupport { private static final long serialVersionUID = 1L; private List<File> file; // 对应jsp中file标签 private List<String> fileFileName; // private List<String> fileContentType; // private String fileName; //获得jsp中pram参数 @SuppressWarnings ( "deprecation" ) // 文件上传 public String uploadFiile() throws Exception { String root = ServletActionContext.getServletContext().getRealPath( "/upload" ); // 上传路径 System.out.println(root); InputStream inputStream; File destFile; OutputStream os; for ( int i = 0 ; i < file.size(); i++) { inputStream = new FileInputStream(file.get(i)); destFile = new File(root, this .getFileFileName().get(i)); os = new FileOutputStream(destFile); byte [] buffer = new byte [ 400 ]; int length = 0 ; while ((length = inputStream.read(buffer)) > 0 ) { os.write(buffer, 0 , length); } inputStream.close(); os.close(); } HttpServletRequest request = ServletActionContext.getRequest(); request.setAttribute( "fileName" , fileFileName); return SUCCESS; } // 文件下载 public InputStream getDownloadFile() throws FileNotFoundException, UnsupportedEncodingException { System.out.println(getFileName()); // 如果下载文件名为中文,进行字符编码转换 ServletActionContext.getResponse().setHeader( "Content-Disposition" , "attachment;fileName=" + java.net.URLEncoder.encode(fileName, "UTF-8" )); InputStream inputStream = new FileInputStream( "F:/" //使用绝对路径 ,从该路径下载“测试.txt"文件 + this .getFileName()); System.out.println(inputStream); return inputStream; } // 下载 public String downloadFile() throws Exception { return SUCCESS; } public String getFileName() throws UnsupportedEncodingException { return fileName; } public void setFileName(String fileName) throws UnsupportedEncodingException { this .fileName = new String(fileName.getBytes( "ISO8859-1" ), "utf-8" ); } } |
注:属性的 get和set方法已省略。
四、最后是配置文件
1、web.xml配置
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< filter > < filter-name >struts2</ filter-name > < filter-class >org.apache.struts2.dispatcher.FilterDispatcher</ filter-class > </ filter > < filter-mapping > < filter-name >struts2</ filter-name > < url-pattern >/*</ url-pattern > </ filter-mapping > |
2、struts.xml配置
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< struts > < constant name = "struts.i18n.encoding" value = "utf-8" ></ constant > < constant name = "struts.multipart.saveDir" value = "f:\" ></ constant > < package name = "struts2" extends = "struts-default" > < action name = "upload" class = "com.action.UpDownloadAction" method = "uploadFiile" > < result name = "success" >/jsp/result.jsp</ result > < interceptor-ref name = "fileUpload" > <!--maximumSize (可选) - 这个拦截器允许的上传到action中的文件最大长度(以byte为单位). 注意这个参数和在webwork.properties中定义的属性没有关系,默认2MB--> < param name = "maximumSize" >409600</ param > <!--allowedTypes (可选) - 以逗号分割的contentType类型列表(例如text/html), 这些列表是这个拦截器允许的可以传到action中的contentType.如果没有指定就是允许任何上传类型.--> < param name = "allowedTypes" > text/plain </ param > </ interceptor-ref > < interceptor-ref name = "defaultStack" ></ interceptor-ref > </ action > < action name = "download" class = "com.action.UpDownloadAction" method = "downloadFile" > < result name = "success" type = "stream" > <!--指定文件下载类型 application/octet-stream默认值可以下载所有类型 --> < param name = "contentType" > application/txt; </ param > <!-- 指定下载的文件名和显示方式 ,但注意中文名的乱码问题,解决办法是:进行编码处理--> <!--contentDisposition是文件下载的处理方式,包括内联(inline)和附件(attachment), 默认是inline, 使用附件时这样配置:attachment;filename="文件名" 。--> < param name = "contentDisposition" > attachment;filename="${fileName}" </ param > <!--由getDownloadFile()方法获得inputStream--> < param name = "inputName" >downloadFile</ param > <!-- 指定下载文件的缓存大小--> < param name = "bufferSize" >2048</ param > </ result > </ action > </ package > </ struts > |
一个简单的Struts2多文件上传和单文件下载就实现了。
以上就是本文的全部内容,希望对大家的学习有所帮助。