Javaweb中的文件下载实现

需要在响应头部加上一些标示，告诉浏览器这个是文件下载。

如果你用了框架比如struts，需要加如下配置

<result name="success" type="stream">

<param name="contentType">application/octet-streamcharset=ISO8859-1</param>

<param name="inputName">fileStream</param>

<param name="contentDisposition">attachmentfilename="${fileName}"</param>

<param name="bufferSize">2048</param>

</result>

如果没有用框架，就手动在返回对象添加这些contentType

Ajax直接调用后台的下载方法是导出不了文件的，原因是ajax无法接收后台的文件流，所以，需要再次用window.location=url或者window.open(url)下载但是这样 *** 作会有弊端，导出方法会调用两次，第一次是ajax进入导出方法，没有报错的话，就第二次进入方法，

所以不如直接用 window.location=url 下载

import java.io.IOException

import java.io.PrintWriter

import javax.servlet.ServletException

import javax.servlet.http.HttpServlet

import javax.servlet.http.HttpServletRequest

import javax.servlet.http.HttpServletResponse

import com.jspsmart.upload.*

import net.sf.json.JSONObject

import action.StudentAction

public class UploadServlet extends HttpServlet {

public void doGet(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

this.doPost(request, response)

}

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

boolean result=true

SmartUpload mySmartUpload=new SmartUpload()

mySmartUpload.initialize(this.getServletConfig(), request,response)

mySmartUpload.setTotalMaxFileSize(50*1024*1024)//大小限制

mySmartUpload.setAllowedFilesList("doc,docx")//后缀名限制

try {

mySmartUpload.upload()

com.jspsmart.upload.File myFile = mySmartUpload.getFiles().getFile(0)

myFile.saveAs("/file/"+1+".doc")//保存目录

} catch (SmartUploadException e) {

e.printStackTrace()result=false

}

//*****************************//

response.setContentType("text/htmlcharset=UTF-8")

response.setHeader("Cache-Control","no-cache")

PrintWriter out = response.getWriter()

out.print(result)

out.flush()

out.close()

}

}

//我这是ajax方式的，不想这样,把//**********************//以下部分修改就行了

//需要SmartUpload组件，去网上下个就行了，也有介绍的

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