Struts2使用注解实现文件的上传与下载（二）

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接上篇Struts2使用注解实现文件的上传与下载（一），这次介绍使用注解实现文件下载，基本配置与之前的一样，这里重点讲下载的Action写法。

文件下载的Action：DownloadAction.java

package com.figo.action;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.UnsupportedEncodingException;import org.apache.commons.io.FileUtils;import org.apache.struts2.ServletActionContext;import org.apache.struts2.convention.annotation.ParentPackage;import org.apache.struts2.convention.annotation.Results;import org.apache.struts2.convention.annotation.Result;import com.opensymphony.xwork2.ActionSupport;import com.opensymphony.xwork2.ModelDriven;import com.opensymphony.xwork2.Validateable;import com.opensymphony.xwork2.ValidationAwareSupport;/** * 所下载文件相关的的几个属性:文件格式 contentType,  * 获取文件名的方法inputName, * 文件内容（显示的）属性contentDisposition,  * 限定下载文件 缓冲区的值bufferSize * */@Results({ @Result(name = "success", type = "stream", params = { "contentType","application/octet-stream;charset=ISO8859-1", "inputName","inputStream", "contentDisposition","attachment;filename=\"Readme.txt\"", "bufferSize", "4096" }) })public class DownloadAction extends ActionSupport {private static final long serialVersionUID = 8784555891643520648L;private String STORAGEPATH = "/upload/Readme.txt";private String fileName;// 初始的通过param指定的文件名属性private String storageId;private String inputPath;// 指定要被下载的文件路径public String getFileName() {return fileName;}public void setFileName(String fileName) {this.fileName = fileName;}public void setInputPath(String inputPath) {this.inputPath = inputPath;}public String getStorageId() {return storageId;}public void setStorageId(String storageId) {this.storageId = storageId;}// 如果下载文件名为中文，进行字符编码转换public String getDownloadFileName() {String downloadFileName = fileName;try {downloadFileName = new String(downloadFileName.getBytes(),"ISO8859-1");} catch (UnsupportedEncodingException e) {e.printStackTrace();}return downloadFileName;}public InputStream getInputStream() throws Exception {/** * 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 **/return ServletActionContext.getServletContext().getResourceAsStream(STORAGEPATH);}public String execute() throws Exception {return SUCCESS;}}

代码其实很简单，最关键的就是getInputStream()方法，返回一个InputStream实例，还有就是@Results的配置。

测试页面：download.jsp

<%@ page language="java" contentType="text/html; charset=utf-8"pageEncoding="utf-8"%><%@ taglib prefix="s" uri="/struts-tags"%><! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" ><html xmlns="http://www.w3.org/1999/xhtml"><head><title>Download</title></head><body><s:a href="download.action">Download</s:a></body></html>

结果如下：

最后附代码：http://download.csdn.net/detail/sxwyf248/4462899