一、通过链接的方式提供指定类型文件的下载
1、最终功能实现的截图：（点击文件下载链接，下载文件 )
2、核心代码
index.jsp：
1 <%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> 2 <% 3 String path = request.getContextPath(); 4 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; 5 %> 6 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 7 <html> 8 <head> 9 <base href="<%=basePath%>"> 10 11 <title>My JSP ‘index.jsp‘ starting page</title> 12 <meta http-equiv="pragma" content="no-cache"> 13 <meta http-equiv="cache-control" content="no-cache"> 14 <meta http-equiv="expires" content="0"> 15 <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> 16 <meta http-equiv="description" content="This is my page"> 17 </head> 18 <body> 19 <a href="<%=path%>/downloadFile?download=UploadFile/readme.doc">点击链接下载文件</a> 20 </body> 21 </html>
struts.xml：
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE struts PUBLIC
3 "-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
4 "http://struts.apache.org/dtds/struts-2.3.dtd">
5 <struts>
6 <package name="default" namespace="/" extends="struts-default">
7 <action name="downloadFile" class="com.thanlon.action.DownloadFileAction">
8 <result name="success" type="stream"><!-- result类型是流(stream)类型 -->
9 <param name="inputName">inputStream</param><!-- inputName指向被下载文件的来源,对应Action中返回的InputStream -->
10 <param name="contentType">${contentType}</param><!-- 下载的内容类型，如图片类型、文档类型等…… -->
11 <param name="contentDisposition">
12 <!-- 指定文件下载的处理方式，内联(inline)和附件(attachment)两种方式，attachment会弹出文件保存对话框 -->
13 attachment;filename=${filename}
14 </param>
15 </result>
16 </action>
17 </package>
18 </struts>
DownloadFileAction.java：
1 package com.thanlon.action;
2
3 import java.io.InputStream;
4
5 import org.apache.struts2.ServletActionContext;
6
7 import com.opensymphony.xwork2.Action;
8
9 public class DownloadFileAction implements Action {
10
11 private String downloadPath;// 下载的路径
12 private String contentType;// 下载文件的类型
13 private String fileName;// 文件类型
14
15 public String getDownloadPath() {
16 return downloadPath;
17 }
18
19 public void setDownloadPath(String downloadPath) {
20 this.downloadPath = downloadPath;
21 }
22
23 public String getContentType() {
24 return contentType;
25 }
26
27 public void setContentType(String contentType) {
28 this.contentType = contentType;
29 }
30
31 public String getFileName() {
32 return fileName;
33 }
34
35 public void setFileName(String fileName) {
36 this.fileName = fileName;
37 }
38
39 @Override
40 public String execute() throws Exception {
41 // TODO Auto-generated method stub
42 downloadPath = ServletActionContext.getRequest().getParameter(
43 "download");
44 System.out.println(downloadPath);// downloadPath为相对路径，打印出“/UploadFile/readme.doc”
45 int position = downloadPath.lastIndexOf("/");// 借助lastIndexOf函数，从右向左查找第一个/
46 System.out.println(position);// 打印"/"所造的坐标
47 if (position > 0) {
48 fileName = downloadPath.substring(position + 1);// 得到文件的名字(全名，带后缀)
49 System.out.println(fileName);// 輸出文件名，本例輸出readme.doc
50 } else {
51 fileName = downloadPath;
52 }
53 contentType = "application/msword";// 指定下载问文件的类型
54 return SUCCESS;
55 }
56
57 /**
58 * 返回InputStream
59 *
60 * @return
61 */
62 public InputStream getInputStream() {
63 InputStream inputStream = ServletActionContext.getServletContext()
64 .getResourceAsStream(downloadPath);
65 // System.out.println(inputStream);输出inputStream，如果为null表示路径出错
66 return inputStream;
67 }
68 }
附：个人网站www.nxl123.cn(后台采用Python Flask框架搭建，2019年1月1日将升级完成并正式启用。哎，本人是学生狗呢！网站做的不好希望大家多多提意见或建议吧！？别骂我、打我就好，嘿嘿！……以后SEO什么的还得多向大家学习……)
原文地址：https://www.cnblogs.com/qikeyishu/p/9155415.html
时间： 2024-10-18 16:50:17