本文实例为大家分享了java文件上传下载的具体代码，供大家参考，具体内容如下
文件上传
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@requestmapping(value="/uploadfile",method=requestmethod.post)
public resultobject uploadfiles(@requestparam("file")multipartfile file,httpservletrequest request){
resultobject rs = null;//返回上传完成信息
string uploaddir = "files";//上传目录,文件保存在webapp下的files文件中
if(!file.isempty()) {
//可以对user做一些操作如存入数据库
//以下的代码是将文件file重新命名并存入tomcat的webapp目录下项目的下级目录
string filerealname = file.getoriginalfilename(); //获得原始文件名;
/*int pointindex = filerealname.indexof("."); //点号的位置
string filesuffix = filerealname.substring(pointindex); //截取文件后缀
uuid fileid = uuid.randomuuid(); //生成文件的前缀包含连字符
string savedfilename = fileid.tostring().replace("-", "").concat(filesuffix); //文件存取名
*/
string saveddir = request.getsession().getservletcontext().getrealpath(uploaddir); //获取服务器指定文件存取路径
file savedfile = new file(saveddir, filerealname);
boolean iscreatesuccess;
try {
iscreatesuccess = savedfile.createnewfile();
if (iscreatesuccess) {
file.transferto(savedfile); //转存文件
rs = resultobject.getsuccessresult("上传文件成功");
long size = file.getsize();//获取文件大小
rs.setdata(uploaddir+filerealname);
}else{
rs = resultobject.getfailresult("请修改文件名,重新上传");
}
} catch (ioexception e) {
e.printstacktrace();
}
}else{
rs = resultobject.getfailresult("文件不能为空");
}
return rs;
}
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文件下载
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@requestmapping(value = "/filterpermission/appdownload", method = requestmethod.get)
public void appdownload(httpservletrequest request, httpservletresponse response) {
//url是上面文件上传的url
download(url,request,response);
}
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public string download(string filepath, httpservletrequest request, httpservletresponse response) {
bufferedinputstream bis = null;
bufferedoutputstream bos = null;
try {
//获取文件名
string filename = filepath.substring(filepath.lastindexof("/")+1);
response.setcharacterencoding("utf-8");
response.setcontenttype("application/octet-stream");
//response.setcontenttype("application/force-download");
//处理下载弹出框名字的编码问题
response.setheader("content-disposition", "attachment;filename="
+ new string( filename.getbytes("gb2312"), "iso8859-1" ));
//获取文件的下载路径
string path = request.getsession().getservletcontext().getrealpath(filepath);
//利用输入输出流对文件进行下载
inputstream inputstream = new fileinputstream(new file(path));
//设置文件大小
response.setheader("content-length", string.valueof(inputstream.available()));
bis = new bufferedinputstream(inputstream);//构造读取流
bos = new bufferedoutputstream(response.getoutputstream());//构造输出流
byte[] buff = new byte[1024];
int bytesread;
//每次读取缓存大小的流，写到输出流
while (-1 != (bytesread = bis.read(buff, 0, buff.length))) {
bos.write(buff, 0, bytesread);
}
response.flushbuffer();//将所有的读取的流返回给客户端
} catch (filenotfoundexception e) {
e.printstacktrace();
} catch (ioexception e) {
e.printstacktrace();
}finally{
try{
if(null != bis){
bis.close();
}
if(null != bos){
bos.close();
}
}catch(ioexception e){
system.out.println("下载文件失败,"+"文件路径:"+filepath+e);
logger.error("文件下载失败!", e);
}
}
// 返回值要注意，要不然就出现下面这句错误！
//java+getoutputstream() has already been called for this response
return null;
}
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以上所述是小编给大家介绍的java文件上传下载详解整合，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对服务器之家网站的支持！
原文链接：https://www.cnblogs.com/gczmn/p/9921479.html