Struts2下载

　　　　<action name="testDownload" class="com.download.file.DownloadAction">
            <result name="success" type="stream"></result>
        </action>

package com.download.file;

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;    //指定文件输入流的 getter 定义的那个属性的名字. 默认为 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 {
        contentType="text/txt";
        contentDisposition = "attachment;filename=测试下载.txt";
        ServletContext servletContext = 
                ServletActionContext.getServletContext();
        String fileName = servletContext.getRealPath("/files/测试下载.txt");
        inputStream = new FileInputStream(fileName);
        contentLength = inputStream.available();
        return super.execute();
    }
    
}