Servlet实现文件上传时候出现了错误，紧急求救！！

你有没设置表单的类型？

没有的话加上 enctype="multipart/form-data"

DataBaseConnection db=new DataBaseConnection();
db.setAuthor(author);
java.io.File f=new java.io.File("../webapps/OpenSource/"+author);
String path="../webapps/OpenSource/";
if(f.exists()==false)
{
f.mkdir();
}
try{
SmartUpload su = new SmartUpload();

su.initialize(servletconfig, request, response);
su.setMaxFileSize(900000000);
su.setTotalMaxFileSize(900000000);
su.setAllowedFilesList("chm,doc,txt,rar,java,zip,jar,sql,pdf,ppt,xls");
su.setDeniedFilesList("exe,bat,jsp,htm,html,,");
su.upload();
for (int i=0;i {
com.jspsmart.upload.File file = su.getFiles().getFile(i);
if (file.isMissing()) continue;
file.saveAs(path+author+"/" + file.getFileName());
session.setAttribute("filename",file.getFileName());
}
session.setAttribute("message","上传成功!");
session.setAttribute("state","true");
response.sendRedirect("../OpenSource/index.jsp");
}
catch(Exception e){

e.printStackTrace();
session.setAttribute("message","上传失败!");
response.sendRedirect("../OpenSource/index.jsp");
}