Spring Mvc下实现以文件流方式下载文件的方法示例
项目中需要对一个点击事件进行下载操作，同时通过点击事件，已经可以从jsp页面获取到需要访问的URL和下载的文件名（数据库获取，jsp页面显示）。点击事件JS如下：
functiondownloadFile(filePath,fileName){
fileName=fileName.substr(0,fileName.lastIndexOf("."));
$.ajax({
async:false,
cache:false,
type:'get',
dataType:"json",
url:RootPath()+"/checkDownload",//请求的action路径
data:{url:filePath},
error:function(){//请求失败处理函数
alert("下载失败");
},
success:function(json){//请求成功后处理函数。
varcode=json.code;
if(code){
window.location.href=RootPath()+"/todownload?url="+filePath+"&name="+fileName;
}else{
layer.alert(fileName+'文件不存在');
}
}
});
}
该ajax调用后台（checkDownload）方法，首先判断从该url能否获得指定下载的文件，如果获取不到，方法返回参数code=0，页面弹出“...文件不存在”。
@RequestMapping("/checkDownload")
@ResponseBody
publicResultcheckDownload(Stringurl,HttpServletResponseresponse){
Resultresult=Result.createSuccessResult();
HttpURLConnectionconn=null;
try{
URLpath=newURL(url);
conn=(HttpURLConnection)path.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5*1000);
conn.getInputStream();//通过输入流获取数据
}catch(IOExceptionex){
result.setCode(0);
ex.printStackTrace();
}finally{
if(conn!=null){
conn.disconnect();
}
}
returnresult;
}
如果checkDownload方法中能够正确获得资源，方法返回参数code=1，ajax成功执行：window.location.href=RootPath()+"/todownload?url="+filePath+"&name="+fileName; 调用（todownload)方法，传入url和name，执行文件下载。
@RequestMapping("/todownload")
@ResponseBody
publicvoiddownload(Stringurl,Stringname,HttpServletResponseresponse){
HttpURLConnectionconn=null;
try{
Filefile=newFile(url);
//取得文件的后缀名。
Stringext=file.getName().substring(file.getName().lastIndexOf(".")+1).toLowerCase();
StringBufferbuffername=newStringBuffer(name);
Stringfilename=buffername.append(".").append(ext).toString();
URLpath=newURL(url);
conn=(HttpURLConnection)path.openConnection();
conn.setRequestMethod("GET");
conn.setConnectTimeout(5*1000);
InputStreamfis=conn.getInputStream();//通过输入流获取数据
byte[]buffer=readInputStream(fis);
if(null!=buffer&&buffer.length>0){
//清空response
response.reset();
//设置response的Header
response.addHeader("Content-Disposition","attachment;filename="+newString((filename).getBytes("GBK"),"ISO8859_1"));
response.addHeader("Content-Length",""+buffer.length);
OutputStreamtoClient=response.getOutputStream();
response.setContentType("application/octet-stream");
toClient.write(buffer);
toClient.flush();
toClient.close();
}
}catch(IOExceptionex){
ex.printStackTrace();
}finally{
if(conn!=null){
conn.disconnect();
}
}
}
/**
*从输入流中获取数据
*@paraminStream输入流
*@return
*@throwsException
*/
privatebyte[]readInputStream(InputStreamfis)throwsIOException{
ByteArrayOutputStreamoutStream=newByteArrayOutputStream();
byte[]buffer=newbyte[1024];
intlen=0;
while((len=fis.read(buffer))!=-1){
outStream.write(buffer,0,len);
}
fis.close();
returnoutStream.toByteArray();
}
PS：SpringMVC文件流形式下载(返回)视频文件
importio.swagger.annotations.Api;
importio.swagger.annotations.ApiOperation;
importorg.springframework.stereotype.Controller;
importorg.springframework.web.bind.annotation.RequestMapping;
importorg.springframework.web.bind.annotation.RequestMethod;
importorg.springframework.web.bind.annotation.RestController;
importjavax.servlet.http.HttpServletResponse;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.IOException;
importjava.io.OutputStream;
importjava.net.URLEncoder;
/**
*文件流形式下载视频
*@authorFrontNg
*@date2019-05-2309:25
**/
@Controller
@RequestMapping(value="/download")
@Api(value="下载",tags="下载")
publicclassDownloadController{
@ApiOperation(value="下载视频")
@RequestMapping(method=RequestMethod.GET)
publicvoiddownload(HttpServletResponseresponse)throwsIOException{
Filefile=newFile("/Users/front/Downloads/123.mp4");
FileInputStreaminputStream=newFileInputStream(file);
byte[]data=newbyte[(int)file.length()];
intlength=inputStream.read(data);
inputStream.close();
StringfileName=URLEncoder.encode("文件流形式视频.mp4","UTF-8");
response.setContentType("application/octet-stream;charset=UTF-8");
response.setHeader("Content-Disposition","attachment;filename=\""+fileName+"\"");
response.addHeader("Content-Length",""+data.length);
OutputStreamstream=response.getOutputStream();
stream.write(data);
stream.flush();
stream.close();
}
}
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持毛票票。