简易版 ：文件的下载
项目结构：
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Action DownLoadAction.java
package com.baidu.download;
import java.io.FileInputStream;
import java.io.InputStream;
import javax.servlet.ServletContext;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class DownLoadAction extends ActionSupport {
private static final long serialVersionUID = 1L;
private String contentType; //结果类型
private long contentLength; // 下载的文件的长度
private String contentDisposition;//设定 Content-Dispositoin 响应头. 该响应头指定接应是一个文件下载类型, 一般取值为 attachment;filename="document.pdf".
private InputStream inputStream;
public String getContentType() {
return contentType;
}
public long getContentLength() {
return contentLength;
}
public String getContentDisposition() {
return contentDisposition;
}
public InputStream getInputStream() {
return inputStream;
}
@Override
public String execute() throws Exception {
//确定各个成员变量的值
contentType = "image/jpg";
contentDisposition = "attachment;filename=wolf.jpg";
ServletContext context = ServletActionContext.getServletContext();
String fileName = context.getRealPath("/files/wolf.jpg");
inputStream = new FileInputStream(fileName);
contentLength = inputStream.available();
System.out.println(contentLength);
return super.execute();
}
}
配置：
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="testDownLoad" class="com.baidu.download.DownLoadAction"> <!-- 下面三个参数需要动态提供 contentType: 结果类型 contentLength: 下载的文件的长度 contentDisposition: 设定 Content-Dispositoin 响应头. 该响应头指定接应是一个文件下载类型, 一般取值为 attachment;filename="document.pdf". 下面一个参数可以取默认值- inputName: 指定文件输入流的 getter 定义的那个属性的名字. 默认为 inputStream 下面三个参数可以在struts.xml 中配置 bufferSize: 缓存的大小. 默认为 1024 allowCaching: 是否允许使用缓存 默认值：true contentCharSet: 指定下载的字符集 --> <result type="stream"> <param name="bufferSize">2048</param> <param name="allowCaching">true</param> <param name="contentCharSet">UTF-8</param> </result> </action> </package> </struts>
页面：
download.jsp
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<a href="testDownload">Down Load </a>
</body>
</html>