Java File Operations

1. Create directory

<% @ Page contenttype = "text/html; charset = gb2312" %>
<%
String filepath = "C:/AAA /";
Filepath = filepath. tostring (); // Chinese Conversion
Java. Io. File myfilepath = new java. Io. File (filepath );
If (! Myfilepath. exists ())
Myfilepath. mkdir ();
%>

2. Create a file

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String filepath = "C:/harhat.txt ";
Filepath = filepath. tostring ();
File myfilepath = new file (filepath );
If (! Myfilepath. exists ())
Myfilepath. createnewfile ();
Filewriter resultfile = new filewriter (myfilepath );
Printwriter myfile = new printwriter (resultfile );
String strcontent = "Chinese test". tostring ();
Myfile. println (strcontent );
Resultfile. Close ();
%>

3. Delete an object

<% @ Page contenttype = "text/html; charset = gb2312" %>
<%
String filepath = "C:/withdrawal ticket .xls ";
Filepath = filepath. tostring ();
Java. Io. File mydelfile = new java. Io. File (filepath );
Mydelfile. Delete ();
%>

4. File copy

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
Int bytesum = 0;
Int byteread = 0;
File: // readTo stream
Inputstream instream = new fileinputstream ("C:/aaa.doc ");
Fileoutputstream FS = new fileoutputstream ("D:/aaa.doc"); byte [] buffer = new byte [1444];
Int length;
While (byteread = instream. Read (buffer ))! =-1)
{
Out. println ("<DT> <B>" + byteread + "</B> </DT> ");
Bytesum + = byteread;
System. Out. println (bytesum );
FS. Write (buffer, 0, byteread );
}
Instream. Close ();
%>

5. Copy the entire folder

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<% String url1 = "C:/AAA ";
String url2 = "D:/Java /";
(New file (url2). mkdirs ();
File [] file = (new file (url1). listfiles ();
For (INT I = 0; I <file. length; I ++ ){
If (file [I]. isfile ()){
File [I]. tostring ();
Fileinputstream input = new fileinputstream (file [I]);
Fileoutputstream output = new fileoutputstream (url2 + "/" + (file [I]. getname (). tostring ());
Byte [] B = new byte [1, 1024*5];
Int Len;
While (LEN = input. Read (B ))! =-1 ){
Output. Write (B, 0, Len );
}
Output. Flush ();
Output. Close ();
Input. Close ();
}
}
%>

6. File Download

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String filename = "zsc104.swf". tostring ();
// Reading the stream
Inputstream instream = new fileinputstream ("C:/zsc104.swf ");
// Set the output format
Response. Reset ();
Response. setcontenttype ("bin ");
Response. addheader ("content-disposition", "attachment; filename =/" "+ filename + "/"");
// Cyclically retrieve the data in the stream
Byte [] B = new byte [100];
Int Len;
While (LEN = instream. Read (B)> 0)
Response. getoutputstream (). Write (B, 0, Len );
Instream. Close ();
%>

7. Download files from database fields

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. SQL. *" %>
<% @ Page import = "Java. Lang. *" %>
<% @ Page import = "Java. Io. *" %>
<% @ Page import = "com. jspsmart. Upload. *" %>
<% @ Page import = "dbstep. idbmanager2000. *" %>
<%
Int bytesum = 0;
Int byteread = 0;
// Open the database
Resultset result = NULL;
String SQL = NULL;
Preparedstatement prestmt = NULL;
Dbstep. idbmanager2000 dbaobj = new dbstep. idbmanager2000 ();
Dbaobj. openconnection ();
// Obtain data in the database
SQL = "select * From t_local_zhongzhuan ";
Result = dbaobj. executequery (SQL );
Result. Next ();

File: // read data from the database to the stream
Inputstream instream = result. getbinarystream ("content ");
Fileoutputstream FS = new fileoutputstream ("C:/dffdsafd.doc ");

Byte [] buffer = new byte [1444];
Int length;
While (byteread = instream. Read (buffer ))! =-1)
{
Out. println ("<DT> <B>" + byteread + "</B> </DT> ");
Bytesum + = byteread;
System. Out. println (bytesum );
FS. Write (buffer, 0, byteread );
}
%>

8. Save a webpage as a file

<% @ Page import = "Java. Text. *" %>
<% @ Page import = "Java. util. *" %>
<% @ Page import = "Java. Io. *" %>
<% @ Page import = "java.net. *" %>
<%
URL stdurl = NULL;
Bufferedreader stdin = NULL;
Printwriter stdout = NULL;
Try {
Stdurl = new URL ("http://www.163.com ");
}
Catch (malformedurlexception e ){
Throw E;
}

Try {
Stdin = new bufferedreader (New inputstreamreader (stdurl. openstream ()));
Stdout = new printwriter (New bufferedwriter (New filewriter ("C:/163.html ")));
}
Catch (ioexception e ){
}

/*** Read the page specified by the URL as a stream and write it as a specified file ***/
Try {
String strhtml = "";
While (strhtml = stdin. Readline ())! = NULL ){
Stdout. println (strhtml );
}
}
Catch (ioexception e ){
Throw E;
}
Finally {
Try {
If (stdin! = NULL)
Stdin. Close ();
If (stdout! = NULL)
Stdout. Close ();
}
Catch (exception e ){
System. Out. println (E );
}
}
%>

9. Download online files directly

<% @ Page import = "Java. Io. *" %>
<% @ Page import = "java.net. *" %>
<%
Int bytesum = 0;
Int byteread = 0;

URL url = new URL ("http://pimg.163.com/sms/micheal/logo.gif ");
Urlconnection conn = URL. openconnection ();
Inputstream instream = conn. getinputstream ();
Fileoutputstream FS = new fileoutputstream ("C:/abc.gif ");

Byte [] buffer = new byte [1444];
Int length;
While (byteread = instream. Read (buffer ))! =-1)
{
Out. println ("<DT> <B>" + byteread + "</B> </DT> ");
Bytesum + = byteread;
System. Out. println (bytesum );
FS. Write (buffer, 0, byteread );
}
%>

10. Read files by row
<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
Filereader myfilereader = new filereader ("C:/harhat.txt ");
Bufferedreader mybufferedreader = new bufferedreader (myfilereader );
String mystring = NULL;
String resultstring = new string ();
While (mystring = mybufferedreader. Readline ())! = NULL)
{Resultstring = resultstring + mystring + "<br> ";
}
Out. println (resultstring );
Myfilereader. Close ();
%>

11. The field files in the database are directly downloaded to the client.
<% @ Page import = "Java. SQL. *" %>
<% @ Page import = "Java. Lang. *" %>
<% @ Page import = "Java. Io. *" %>
<% @ Page import = "com. jspsmart. Upload. *" %>
<% @ Page import = "dbstep. idbmanager2000. *" %>
<%
String filename = "bb.doc". tostring ();
// Open the database
Resultset result = NULL;
String SQL = NULL;
Preparedstatement prestmt = NULL;
Dbstep. idbmanager2000 dbaobj = new dbstep. idbmanager2000 ();
Dbaobj. openconnection ();
// Obtain data in the database
SQL = "select * From marklist order by markdate DESC ";
Result = dbaobj. executequery (SQL );
Result. Next ();
// Read data from the database to the stream
Inputstream in = result. getbinarystream ("markbody ");
// Set the output format
Response. Reset ();
Response. setcontenttype ("application/MSWord ");
Response. addheader ("content-disposition", "attachment; filename =/" "+ filename + "/"");
// Cyclically retrieve the data in the stream
Byte [] B = new byte [1024];
Int Len;
While (LEN = in. Read (B)> 0)
Response. getoutputstream (). Write (B, 0, Len );
In. Close ();
%>

12. Folder Traversal
<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String url1 = "C:/AAA ";
File F = (new file (url1 ));
If (F. isdirectory ()){
File [] Fe = f. listfiles ();
Go_on:
For (INT I = 0; I <Fe. length; I ++ ){
If (Fe [I]. isdirectory ()){
File [] fe1 = Fe [I]. listfiles ();
For (Int J = 0; j <fe1.length; j ++ ){
If (fe1 [J]. isdirectory ())
Continue go_on;
Out. println (fe1 [J]. tostring ());
}
}
Else Out. println (Fe [I]. tostring ());
}
}

%>

13. Move a file by character encoding

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String ret = new string ();
Try
{
Byte [] bytes = new byte [1, 102400];
Inputstream in = new fileinputstream ("C:/aaa.doc ");
In. Read (bytes );
Ret = new sun. Misc. base64encoder (). encode (bytes); // specific encoding method
In. Close ();
}
Catch (filenotfoundexception E)
{
E. printstacktrace ();
}
Catch (Java. Io. ioexception ex)
{
Ex. printstacktrace ();
}
Out. println (RET );

Byte [] bytes = new sun. Misc. base64decoder (). decodebuffer (RET );
Java. Io. bytearrayinputstream instream = new java. Io. bytearrayinputstream (bytes );
Byte [] buffer = new byte [1444];
Fileoutputstream FS = new fileoutputstream ("D:/aaa.doc ");
Int bytesum = 0;
Int byteread = 0;
While (byteread = instream. Read (buffer ))! =-1)
{
Bytesum + = byteread;
FS. Write (buffer, 0, byteread );
}
%>

14. Encode the file into a base64 string
<%
String ret = new string ();
Byte [] bytes = new byte [1, 1024];
String AA = "aaaa ";
Bytes = AA. getbytes ();
Ret = new sun. Misc. base64encoder (). encode (bytes); // specific encoding method
Bytes = new sun. Misc. base64decoder (). decodebuffer (RET );
AA = new string (bytes );
Out. println (AA );
%>

12. Folder Traversal
<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String url1 = "C:/AAA ";
File F = (new file (url1 ));
If (F. isdirectory ()){
File [] Fe = f. listfiles ();
Go_on:
For (INT I = 0; I <Fe. length; I ++ ){
If (Fe [I]. isdirectory ()){
File [] fe1 = Fe [I]. listfiles ();
For (Int J = 0; j <fe1.length; j ++ ){
If (fe1 [J]. isdirectory ())
Continue go_on;
Out. println (fe1 [J]. tostring ());
}
}
Else Out. println (Fe [I]. tostring ());
}
}

%>

13. Move a file by character encoding

<% @ Page contenttype = "text/html; charset = gb2312" %>
<% @ Page import = "Java. Io. *" %>
<%
String ret = new string ();
Try
{
Byte [] bytes = new byte [1, 102400];
Inputstream in = new fileinputstream ("C:/aaa.doc ");
In. Read (bytes );
Ret = new sun. Misc. base64encoder (). encode (bytes); // specific encoding method
In. Close ();
}
Catch (filenotfoundexception E)
{
E. printstacktrace ();
}
Catch (Java. Io. ioexception ex)
{
Ex. printstacktrace ();
}
Out. println (RET );

Byte [] bytes = new sun. Misc. base64decoder (). decodebuffer (RET );
Java. Io. bytearrayinputstream instream = new java. Io. bytearrayinputstream (bytes );
Byte [] buffer = new byte [1444];
Fileoutputstream FS = new fileoutputstream ("D:/aaa.doc ");
Int bytesum = 0;
Int byteread = 0;
While (byteread = instream. Read (buffer ))! =-1)
{
Bytesum + = byteread;
FS. Write (buffer, 0, byteread );
}
%>

14. Encode the file into a base64 string
<%
String ret = new string ();
Byte [] bytes = new byte [1, 1024];
String AA = "aaaa ";
Bytes = AA. getbytes ();
Ret = new sun. Misc. base64encoder (). encode (bytes); // specific encoding method
Bytes = new sun. Misc. base64decoder (). decodebuffer (RET );
AA = new string (bytes );
Out. println (AA );
%>