一、Struts2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：
<%@ 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%>" rel="external nofollow" rel="external nofollow" > <title>My JSP 'index.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">
</head>
<body>
<a href="<%=path%>/downloadFile?download=UploadFile/readme.doc" rel="external nofollow" rel="external nofollow" >点击链接下载文件</a>
</body>
</html>
struts.xml：
<?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>
<package name="default" namespace="/" extends="struts-default">
<action name="downloadFile" class="com.thanlon.action.DownloadFileAction">
<result name="success" type="stream"><!-- result类型是流(stream)类型 -->
<param name="inputName">inputStream</param><!-- inputName指向被下载文件的来源,对应Action中返回的InputStream -->
<param name="contentType">${contentType}</param><!-- 下载的内容类型，如图片类型、文档类型等…… -->
<param name="contentDisposition">
<!-- 指定文件下载的处理方式，内联(inline)和附件(attachment)两种方式，attachment会弹出文件保存对话框 -->
attachment;filename=${filename}
</param>
</result>
</action>
</package>
</struts>
DownloadFileAction.java：
package com.thanlon.action; import java.io.InputStream; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.Action; public class DownloadFileAction implements Action { private String downloadPath;// 下载的路径
private String contentType;// 下载文件的类型
private String fileName;// 文件类型 public String getDownloadPath() {
return downloadPath;
} public void setDownloadPath(String downloadPath) {
this.downloadPath = downloadPath;
} public String getContentType() {
return contentType;
} public void setContentType(String contentType) {
this.contentType = contentType;
} public String getFileName() {
return fileName;
} public void setFileName(String fileName) {
this.fileName = fileName;
} @Override
public String execute() throws Exception {
// TODO Auto-generated method stub
downloadPath = ServletActionContext.getRequest().getParameter(
"download");
System.out.println(downloadPath);// downloadPath为相对路径，打印出“/UploadFile/readme.doc”
int position = downloadPath.lastIndexOf("/");// 借助lastIndexOf函数，从右向左查找第一个/
System.out.println(position);// 打印"/"所造的坐标
if (position > 0) {
fileName = downloadPath.substring(position + 1);// 得到文件的名字(全名，带后缀)
System.out.println(fileName);// 輸出文件名，本例輸出readme.doc
} else {
fileName = downloadPath;
}
contentType = "application/msword";// 指定下载问文件的类型
return SUCCESS;
} /**
* 返回InputStream
*
* @return
*/
public InputStream getInputStream() {
InputStream inputStream = ServletActionContext.getServletContext()
.getResourceAsStream(downloadPath);
// System.out.println(inputStream);输出inputStream，如果为null表示路径出错
return inputStream;
}
}
二、Struts2多种类型(不指定)文件的下载
1、火狐浏览器下测试对比后，很明显可以看出添加资源文件后，下载时文件的类型被设置成文件真实类型。
下面同样是有无资源文件的对比，也是很明显可以看出。使用资源文件的，下载文件时带上了正确的文件后缀。
2、核心代码
index.jsp：
<%@ 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%>" rel="external nofollow" rel="external nofollow" > <title>My JSP 'index.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">
</head>
<body>
<p>下面是举例说明：</p>
<a href="<%=path%>/downloadFile?download=UploadFile/readme.doc" rel="external nofollow" rel="external nofollow" >点击链接下载文件(doc)</a><br>
<a href="<%=path%>/downloadFile?download=UploadFile/thanlon.pdf" rel="external nofollow" >点击链接下载文件(pdf)</a><br>
<a href="<%=path%>/downloadFile?download=UploadFile/demo.gif" rel="external nofollow" >点击链接下载文件(gif)</a><br>
<a href="<%=path%>/downloadFile?download=UploadFile/logo.png" rel="external nofollow" >点击链接下载文件(png)</a>
</body>
</html>
struts.xml：
与上一例（Struts2指定类型文件的下载）的struts.xml相同
DownloadFileAction.java：
package com.thanlon.action; import java.io.InputStream; import org.apache.struts2.ServletActionContext; import com.opensymphony.xwork2.Action;
import com.opensymphony.xwork2.ActionSupport; public class DownloadFileAction extends ActionSupport { private String downloadPath;// 下载的路径
private String contentType;// 下载文件的类型
private String fileName;// 文件类型 public String getDownloadPath() {
return downloadPath;
} public void setDownloadPath(String downloadPath) {
this.downloadPath = downloadPath;
} public String getContentType() {
return contentType;
} public void setContentType(String contentType) {
this.contentType = contentType;
} public String getFileName() {
return fileName;
} public void setFileName(String fileName) {
this.fileName = fileName;
} @Override
public String execute() throws Exception {
// TODO Auto-generated method stub
downloadPath = ServletActionContext.getRequest().getParameter(
"download");
System.out.println(downloadPath);// downloadPath为相对路径，打印出“/UploadFile/readme.doc”
int position = downloadPath.lastIndexOf("/");// 借助lastIndexOf函数，从右向左查找第一个/
// System.out.println(position);// 打印"/"所在的坐标
if (position > 0) {
fileName = downloadPath.substring(position + 1);// 得到文件的名字(全名，带后缀)
System.out.println(fileName);// 輸出文件名
} else {
fileName = downloadPath;
}
int extPos = fileName.lastIndexOf(".");
System.out.println(extPos);
String contentTypeKey = null;
if (extPos > 0) {
contentTypeKey = "struts.contentType" + fileName.substring(extPos);//带.的后缀
System.out.println(contentTypeKey);
}else {
contentTypeKey = "struts.contentType.txt";
//如果没有在属性文件中指定类型：如果是文件，则下载的文件默认后缀为txt文件类型;如果是图片则不会是txt类型，会是自身类型，或者特殊类型，比如jpg会是jfif类型。
}
contentType =getText(contentTypeKey);// 指定下载问文件的类型此类继承了ActionSupport，直接使用getText()函数
System.out.println(contentTypeKey);
return SUCCESS;
}
/**
* 返回InputStream
*
* @return
*/
public InputStream getInputStream() {
InputStream inputStream = ServletActionContext.getServletContext()
.getResourceAsStream(downloadPath);
// System.out.println(inputStream);输出inputStream，如果为null表示路径出错
return inputStream;
}
}
DownloadFileAction.properties：
struts.contentType.gif=image/gif
struts.contentType.jpg=image/jpg
struts.contentType.jpeg=image/jpeg
struts.contentType.bmp=image/bmp
struts.contentType.png=image/png
struts.contentType.txt=text/plain
struts.contentType.swf=application/x-shockwave-flash
struts.contentType.doc=application/msword
struts.contentType.xls=application/vnd.ms-excel
struts.contentType.pdf=application/pdf
struts.contentType.ppt=application/vnd.ms-powerpoint
struts.contentType.exe=application/octet-stream
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