jsp页面如何实现下载文档

jsp页面下载文档是宴销在jsp中有一个a标签 ，当用户点击a标签的时候下载文件。

一般采用链州href属性直接指向一个服务器地址，只要链接的文件存在,就会给出d出保存对话框.

点击a标签 先执行onclick事件，再请求href中指向的地址。

前端jsp：

<a href="#" onclick="javascript:downloadtest('${app.id}')" id="pluginurl" style="color: #83AFE2text-decoration:underline"></a>

然后在js中：

function downloadtest(id){

var url = "<%=request.getContextPath()%>/app/download" + "/" + id

$("#pluginurl").attr("href",url)

}

后台处理下载晌唤游逻辑的java代码：

/**

* 下载文件

* @param id appid

* @param response

*/

@RequestMapping(value="/download/{id}")

public void download(@PathVariable String id, HttpServletResponse response){

String filepath = ""

Result result = appService.getAppById(id)

App app = (App) result.getMap().get("app")

if(app == null){

return

}

filepath = app.getUrl()

File file = new File(filepath)

InputStream inputStream = null

OutputStream outputStream = null

byte[] b= new byte[1024]

int len = 0

try {

inputStream = new FileInputStream(file)

outputStream = response.getOutputStream()

response.setContentType("application/force-download")

String filename = file.getName()

filename = filename.substring(36, filename.length())

response.addHeader("Content-Disposition","attachmentfilename=" + URLEncoder.encode(filename, "UTF-8"))

response.setContentLength( (int) file.length( ) )

while((len = inputStream.read(b)) != -1){

outputStream.write(b, 0, len)

}

} catch (Exception e) {

e.printStackTrace()

}finally{

if(inputStream != null){

try {

inputStream.close()

inputStream = null

} catch (IOException e) {

e.printStackTrace()

}

}

if(outputStream != null){

try {

outputStream.close()

outputStream = null

} catch (IOException e) {

e.printStackTrace()

}

}

}

}

<%@pagelanguage="java" import="java.io.*,java.net.*" contentType="application/x-msdownload"pageEncoding="UTF-8"%><%

//关于文件下载时采用文件流输出的方式处理：

//加上response.reset()，并且所有的％>后面不要山薯换行，包括最后一个；

String url = request.getParameter("url"衫亩)

System.out.print(url)

int k = url.lastIndexOf("\\")

String url1=url.substring(k+1,url.length())

response.reset()//可以加也或唯森可以不加

response.setContentType("application/x-download")

String filedownload = url

String filedisplay = url1

filedisplay = URLEncoder.encode(filedisplay,"UTF-8")

response.addHeader("Content-Disposition","attachmentfilename=" + filedisplay)

OutputStream outp = null

FileInputStream in = null

try

{

outp = response.getOutputStream()

in = new FileInputStream(filedownload)

byte[] b = new byte[1024]

int i = 0

while((i = in.read(b)) >0)

{

outp.write(b, 0, i)

}

out.clear()

out = pageContext.pushBody()

outp.flush()

}

catch(Exception e)

{

System.out.println("Error!")

}

finally

{

if(in != null)

{

in.close()

in = null

}

if(outp != null)

{

outp.close()

outp = null

}

}

%>

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