1 <a href="download/123.rar">123.rar</a>

 1 public class TestAction extends ActionSupport{
 2
 3     public String fileLoad() throws IOException{
 4         String fileName = ServletActionContext.getRequest().getParameter("fileName");
 5         //要处理中文乱码问题
 6         fileName = new String(fileName.getBytes("iso8859-1"),"utf-8");
 7         //要下载的哪个文件
 8         String path = ServletActionContext.getServletContext().getRealPath("/");//得到项目的根目录
 9         InputStream is = new FileInputStream(path+"/download/"+fileName);
10
11         //下载到哪里？客户端
12         HttpServletResponse response = ServletActionContext.getResponse();
13         OutputStream os = response.getOutputStream();
14         //弹出下载的框filename:提示用户下载的文件名
15         response.addHeader("content-disposition", "attachment;filename="+java.net.URLEncoder.encode(fileName,"utf-8"));
16
17         byte[] b = new byte[1024];
18         int size = is.read(b);
19         while(size>0){
20             os.write(b,0,size);
21             size = is.read(b);
22         }
23         is.close();
24         os.close();
25         return null;
26     }
27
28 }

1 <a href="test!fileLoad.action?fileName=A.java">A.java</a>
2
3 <a href="test!fileLoad.action?fileName=jquery.txt">jquery.txt</a>
4
5 <a href="test!fileLoad.action?fileName=中文.txt">中文.txt</a>

1 byte[] b = new byte[1024];
2 int size = is.read(b);
3 while(size>0){
4     os.write(b,0,size);
5     size = is.read(b);
6 }

 1 <struts>
 2    <package name="com.action" extends="struts-default">
 3            <action name="download" class="com.action.FileLoadAction">
 4                <result name="success" type="stream">
 5                    <param name="contentType">application/txt;</param>
 6                    <param name="inputName">downloadFile</param>
 7                    <param name="bufferSize">2048</param>
 8                </result>
 9            </action>
10    </package>
11 </struts>    

 1 public class FileLoadAction extends ActionSupport{
 2     private String fileName;
 3
 4     public String getFileName() {
 5         return fileName;
 6     }
 7     public void setFileName(String fileName) throws UnsupportedEncodingException {
 8         this.fileName = new String(fileName.getBytes("iso8859-1"),"utf-8");
 9     }
10     public InputStream getDownloadFile() throws UnsupportedEncodingException, FileNotFoundException{
11         //attachment为进行文件保存，这个时候还可以附件另一个参数filename表示保存时的缺省名称
12         //inline为在线打开，不进行保存
13         ServletActionContext.getResponse().setHeader("Content-Disposition","attachment;fileName="+ java.net.URLEncoder.encode(fileName, "UTF-8"));
14         HttpServletResponse response = ServletActionContext.getResponse();
15         return new FileInputStream("d:/"+this.getFileName());
16     }
17     public String downloadFile(){
18         return SUCCESS;
19     }
20 }

1 <%@ page language="java" import="java.util.*" pageEncoding="utf-8"%>
2 <%@taglib prefix="s" uri="/struts-tags" %>
3
4 <s:url value="download.action" var="url">
5     <s:param name="fileName">中文.txt</s:param>
6 </s:url>
7 <a href="${url }">点击下载</a>

参数说明 

contentType 

内容类型，和互联网MIME标准中的规定类型一致，例如text/plain代表纯文本，text/xml表示XML，image/gif代表GIF图片，image/jpeg代表JPG图片 

 

inputName 

下载文件的来源流，对应着action类中某个类型为Inputstream的属性名，例如取值为inputStream的属性需要编写getInputStream()方法 

 

contentDisposition 

文件下载的处理方式，包括内联(inline)和附件(attachment)两种方式，而附件方式会弹出文件保存对话框，否则浏览器会尝试直接显示文件。取值为： 

 

attachment;filename="struts2.txt"，表示文件下载的时候保存的名字应为struts2.txt。如果直接写filename="struts2.txt"，那么默认情况是代表inline，浏览器会尝试自动打开它，等价于这样的写法：inline; filename="struts2.txt" 

 

bufferSize 

下载缓冲区的大小