1. 创建action
import java.io.InputStream;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class FileDownloadAction extends ActionSupport {
private String inputPath;
public void setInputPath(String value) {
inputPath = value;
}
//下载用的Action应该返回一个InputStream实例， 该方法对应在result里的inputName属性值为targetFile
public InputStream getTargetFile() throws Exception {
return ServletActionContext.getServletContext().getResourceAsStream(inputPath);
}
public String execute() throws Exception {
return SUCCESS;
}
}
2. 配置struts.xml
<package name="ud" namespace="/ud" extends="default">
<action name="download" class="top.onelala.up2down_load.FileDownloadAction">
<param name="inputPath">images中.gif</param>
<result name="success" type="stream">
<param name="contentType">image/gif</param>
<param name="inputName">targetFile</param>
<param name="contentDisposition">attachment;filename="struts.gif"</param>
<param name="bufferSize">4096</param>
</result>
</action>
</package>
3. 前台页面显示，download.jsp
<li>下载Struts2的Logo：<a href="ud/download.action">下载图形文件</a></li>
**注意：**attachment;filename=“struts.gif”，设置浏览器以下载的方式打开文件，文件下载的时候保存的名字应为struts.gif，如果直接写filename=“struts.gif”，那么默认情况是代表inline，浏览器会尝试自动打开它，此等价于这样的写法：
inline; filename="struts2.txt"
附录：
要下载文件，首先要获取文件列表
创建action
public class DownloadAction extends ActionSupport{
private File[] files;
public String list(){
//取得文件保存路径
String path=ServletActionContext.getServletContext().getRealPath("/upload");
File f=new File(path);
//获取目录下保存的文件
files=f.listFiles();
return "list";
}
//省略get/set
}
配置struts.xml
<action name="*down" class="base.MyFileUpload" method="{1}">
<result name="list">/filelist.jsp</result>
</action>
前台页面显示，filelist.jsp
<body>
<c:forEach items="${files }" var="f">
${f.name}<a href="listdownload.action?filename=${f.name }">下载</a><br>
</c:forEach>
</body>
点击下载链接，将文件名传入后台，
修改action代码
public class DownloadAction extends ActionSupport{
private File[] files;
private String fileName;
public String list(){
//取得文件保存路径
String path=ServletActionContext.getServletContext().getRealPath("/upload");
File f=new File(path);
//获取目录下保存的文件
files=f.listFiles();
return "list";
}
public InputStream getDownloadFile() throws Exception{
String filePath = ServletActionContext.getRequest()
.getServletContext().getRealPath("/upload/"+fileName);
InputStream is = new FileInputStream(new File(filePath));
//解决下载文件名称问题
fileName=URLEncoder.encode(fileName, "UTF-8");
return is;
}
public void setFileName(String fileName) throws UnsupportedEncodingException {
//处理get请求中文乱码
this.fileName = new String(fileName.getBytes("iso8859-1"),"utf-8");
}
public File[] getFiles() {
return files;
}
public void setFiles(File[] files) {
this.files = files;
}
public String getFileName() {
return fileName;
}
}
修改struts.xml文件
<action name="*down" class="base.DownloadAction" method="{1}">
<result name="list">/filelist.jsp</result>
<result type="stream">
<!-- 下载的文件数据存放的方法，该方法返回一个InputStream
例如取值为inputStream的属性需要编写getInputStream()方法-->
<param name="inputName">downloadFile</param>
<!--下载时，客户端显示的下载的文件名 -->
<param name="contentDisposition"> attachment; filename=${fileName}</param>
<!-- 数据的缓冲大小 -->
<param name="bufferSize">1024</param>
</result>
</action>