File establishment / check and delete <% @ page contentty = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%>
file Establish, check and delete title> head> <% string path = request.getRealPath (""); // out.println (path); file f = new file (path, "file.txt "); // out.println (f); // out.println (f.exists ());
IF (F.Exists ()) {// Check if file.txt exists in f.delete (); // Delete file.txt file out.println (Path "//file.txt exists, deleted."); } else {f.createNewFile (); // Create a file named file.txt in the current directory Out.println (Path "//file.txt does not exist,"); // Output is currently Directory path}%>
Catalog / Check and Delete <% @ Page ContentType = "Text / HTML; Charset = GB2312"%> <% @ Page Import = "Java.io. *"%>
directory Establish / Check and Delete Title> head> <% string path = request.getRealPath (""); path = path "// sub"; // will be created directory path file d = new File (path); // Establish a file object representing the SUB directory and gets a reference IF (D.Exists ()) {// check if the SUB directory exists (); out.println ("Sub Directory Presented, deleted ");} else {d.mkdir (); // Establish a subdirectory Out.println (" Sub directory does not exist, established ");}%> body> html>
How to handle virtual directory <% @ Page ContentType = "text = GB2312"%> Java.io. * "%> JSP in JSP How to deal with virtual directory title> head> acquired a virtual directory corresponding to disk path
WEB site main directory location is <% = request.getRealPath ("/") directory location%> font>
JSP page where the <% = request.getRealPath ( "./")%> font> on
JSP pages directory level The location of the directory <% = Request.getRealPath ("../" )% (" "
body> html>
Number of file properties <% @ Page ContentType = "Text / HTML; Charset = GB2312"%> <% @ page import = "java.util.date, java.io. *"%>
File attributes Title> head> <% string path = request.getRealPath ("/"); file f = new file (path, "readdata.txt"); if (F.Exists ()) {%> <% = f.getName ()%> following properties:
file length is:? <% = f.length ()%> <% = f.isFile () " Is the file ":" Not the file "%>
<% = f.Indirectory ()?" Is a directory ":" Not a directory "%>
<% = f.canread ()?" Readable " : "Do not read"%>
<% = f.canwrite ()? "Writable": "Not writable"%>
<% = f.ishidden ()? "Is a hidden file" : "Not hidden file"%>
File's last modification date is: <% = new date (f.lastmodified ())%>
<%} else {f.createNewFile (); // is currently establishment of a directory file named ReaData.txt%> <% = f.getName ()%> following properties:
file length is: <% = f.length ()%> <% = f.isfile ()? "Yes File": "Not File"%>
<% = f.IsDirectory ()? "is a directory": "Not a directory"%>
<% = f.canread "Readable": "Do not read"%>
<% = f.canwrite ()? "Write": "Not Write"%>
<% = f.ishidden )? "It is hidden file": "Not hidden file"%>
File's last modification date is: <% = new date (f.lastmodified ())%>
<%}%> body > html>
Take out the file in the directory <% @ Page ContentType = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%>
Take out the directory File method - list files in the directory title> head> <% string path = request.getRealPath ("/"); file d = new file (path); // Establish the current directory File object for Chinese file file list [] = D.ListFiles (); // acquire file object array Out.println ("
path " directory in the directory: font>
"); for (int i = 0; i ");}}}} Out.println ("
" "directory in the directory: font>
"); for (int i = 0; i ");}}%> body > html> Judging whether it is blank file <% @ Page ContentType = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%> Judgment is a blank file title> head> <% string path = request.getRealPath ("/"); out.println (path); fileReader fr = new fileReader (Path "// Atende .txt "); // Establish a FileReader object, and instantiate to FR // The object generated by the FileReader class uses the READ () method, which can read the next character from the character stream. if (fr.read () == - 1) // determines if the end of the file is read {OUT.PRINT ("There is no data
" in atend.txt file ");} else {Out.println (" Atend Data in .txt file ");} fr.close ();%> body> html>
Read all file data <% @ Page ContentType = "text / html; charSet = GB2312"%> <% @ page import = "java.io. *, Java.lang. *"%>
Read all file data title> head> <% string path = request.getRealPath ("."); fileReader fr = new fileReader (Path "//ReadData.txt") ; // The key is that during the reading, it is to be determined whether the read character has reached the end of the file, and this character is not a broken line in the file, ie it is determined whether the character value is 13. INT c = fr.read (); // reads a character // from the file to determine if the file ends are read, while (c! = - 1) {Out.print ((char) c); // Output Data c = fr.read (); // Continue to read data IF from the file (c == 13) {// Judgment whether it is a broken character out.print ("
"); // Output Branch Label fr.skip (1); // Skose a character //c=fr.read();// read a character}} fr.close ();%> body> html> a line Read data <% @ Page ContentType = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%> file reading title > head> <% string path = request.getRealPath (""); // Get the path of the current directory FileReader fr = new fileReader (Path "//file/inc/t.txt") // Establish a FileReader object, and instantiate to fr bufferedreader br = new bufferedreader (fr); // Establish a BufferedReader object, and instantiate to br string line = br.readline (); // read a string from the file / / Judgment whether the read string is not empty while (line! = Null) {Out.println (line "
"); / / Output data read from the file line = Br.Readline ); // Continue to read a row data from the file} br.close (); // Turn off the bufferedReader object fr.close (); // Off file%> body> html>
Broken characters in the file do not read <% @ page contentty = "text / html; charSet = GB2312"%> <% @ page import = "java.io. *"%>
Slightly not reading title> head> <% string path = request.getRealPath ("."); FileReader fr = new fileReader (Path "//ReadData.txt" );fr .skip (2); // Skip 2 bytes int C = fr.read (); // Read a byte while (c! = - 1) {Out.Print ((char) C); C) = fr.close ();} fr.close ();%> body> html> write data into file <% @ Page ContentType = "text / html; charSet = GB2312"%> <% @ Page Import = "java.io. *"%> Write data title> head> <% string path = request.getRealPath ("."); FileWriter FW = New FileWriter (Path "//WriteData.txt": // establishes FileWriter object, and instantiates FW // write strings into file fw.write ("Hello!"); Fw.write "This book is" JSP programming skills ""); fw.write ("Please give me a lot!"); Fw.write ("email: stride@sina.com"); fw.close ();
FileReader fr = new fileReader (Path "//writeData.txt" ); bufferedReader br = New BufferedReader (fr); // Establish a bufferedReader object, and instantiate to brstring line = br.readline (); // read a line Data OUT.PRINTLN (Line "
"); br.close (); // Close BufferedReader object fr.close ();%> body> html>
<% @ Page contentty = "text / html; charset = GB2312"%> <@ page import = "java.io. *"%>
will write Data Branch of the file title> head> <% string path = request.getRealPath ("."); FileWriter FW = New FileWriter (Path "//writeData.txt "; bufferedwriter BW = New BufferedWriter (fw); bw.write ("Hello!"); bw.write ("This book is" JSP programming skills "."); bw.newline (); // broken bw.write ("Please more Guao! "); Bw.newline (); // Broken BW.WRITE (" email: stride@sina.com "); bw.flush (); // Update data to file fw.close (); // Turning off file stream out.println ("Write file content:
"); fileReader fr = new fileReader (path "//writedata.txt" ); bufferedreader br = new bufferedreader (fr); string line = br .readline (); // reads a line of data while (line! = null) {Out.println (line "
"); line = br.readline ();} fr.close ();%> < / Body> html>