IO流和文件上传下载

inputStream--->

inputstreamReader,fileInputStream,bufferedReader,dataInputStream,objectInputStream,Reader

outputStream-->

outputStreamReader,fileOutputStream,bufferedWriter,dataoutputStream,objectOutputStream,writer

文件操作--->File file=new File(String pathName);---直接通过路径创建

file.separator()-----"/"==="\\","."当前目录".."上一级目录 file.getObsolutePath()--->绝对路径file.isFile()是否为文件 file.isDirectory()是否为目录

File afile=new File(String parent,String child);---由父路径和子路径共同创建文件

file.createNewFile()---创建新文件;file.mkdir()---最后级目录;file.mkdirs()--多级目录;

file.exists()---文件是否存在;file().getName()--获取文件名;file.getPath()--获取路径;file.length()---文件大小(字节)

file.list()----列出文件列表;file.listFiles()---列出所有子文件夹和子文件

文件上传-->servletFileupload

fileUploadServlet核心接口form(enctype=multipart/form-data)DiskFileItemFactory();FileItemFactory();servletFileUpload();setHeaderEncoding();setSizeMax();setFileSizeMax();parseRequest(httpServletRequest);isMultipartContent(httpservletRequest);FileItem();getFieldName();getString();getContentType();getInputStream();getName();writer();delete();

setRepository()------>临时存储路径

core-code--->

DiskFileItemFactory factory=new DiskFileItemFactory();

ServletFileUpload upload=new ServletFileUpload(factory);

upload.setSizeMax(30*1024*1024);

upload.setFileSizeMax(10*1024*1024);

if(upload.isMultipartContent(request)){

List<FileItem> list=upload.parseRequest(request);

for(FileItem item:list){

if(item.isFormField()){

String fieldName=item.getFieldName();

String value=item.getString("UTF-8");

System.out.println("fieldName"+fieldName+",value="+value());

}else{

String name=item.getName();

String uuid=UUID.randomUUID().toString();

name=uuid+name;

String uploadPath=getServletContext().getRealpath("/upload");

File file=new File(uploadPath,name);

item.write(file);

item.delete();

}

}

}