JSP file operations (new, delete, read, write) __js

There are many places in the java/jsp to use the operation of the file, file operation is very simple, the following list of some common methods of file operation

JSP file operations commonly used methods: MkDir () method is used to create a folder Delete () method to remove folders and files The exists () method is to determine whether a folder or file exists The CreateNewFile () method is to create a file The Listfiles () method is to get the files under the folder The Read () method reads the file The ReadLine () method is to read the file in rows The write () method writes a character or string to a file

Here's a sample description of these methods
1. New and deleted directory

MkDir () Method: <%@ page import= "java.io.*"%> <% String Path = Request.getrealpath ("/file/"); String subpath = path+ "Mulu"; File ml = new file (subpath); if (Ml.exists ()) { Ml.delete (); Out.println (path + "folder Mulu has been deleted!"); } Else { Ml.mkdir (); Out.println (path + "folder Mulu Create success!"); } %>

2. New and deleted files

CreateNewFile () Method: <%@ page import= "java.io.*"%> <% String Path = Request.getrealpath ("/file/"); File FileName = new file (path, "File.txt"); if (Filename.exists ()) { Filename.delete (); Out.println (path + "file File.txt file has been deleted!"); } Else { Filename.createnewfile (); Out.println (path + "file File.txt Create success!"); } %>

3. Get the files under the folder

Listfiles () Method: <%@ page import= "java.io.*"%> <% String Path = Request.getrealpath ("/file/"); File FL = new file (path); File list[] = Fl.listfiles (); Out.println ("file list:<br>"); for (int i=0 i < list.length; i++) { Out.println (List[i].getname () + "<br>"); } %>

4. Read the contents of the file

Read () Method: <%@ page import= "java.io.*"%> <% String Path = Request.getrealpath ("/file/"); FileReader FR = new FileReader (path + "File.txt"); Single byte read int c = Fr.read (); while (c!=-1)//Determine whether the end of the file has been read { Out.print ((char) c); Data read from the output c = Fr.read (); Reading data from a file if (c = = 13)//Determine if the break byte { Out.print ("<BR>"); Output Branch Label Fr.skip (1); Skip One byte c = Fr.read (); Read one byte } } Fr.close (); %>

You can also read a file by reading a row

ReadLine () Method: <% BufferedReader br = new BufferedReader (FR); String BRL = Bufferedread.readline (); while (Brl!=null) { Out.println (brl+ "<br>"); BRL = Bufferedread.readline (); } Brl.close (); Fr.close (); %>

5. Write to File

Write () Method: <%@ page import= "java.io.*"%> <% String Path = Request.getrealpath ("/file/"); FileWriter FW = new FileWriter (path + "File.txt"); Fw.write ("hello!"); Fw.write ("I wish you all a happy learning jsp." "); Fw.write ("I hope this article can give you an understanding of the ' JSP file Operation ' Help.") "); Fw.close (); %> <a href= "Http://localhost:8080/k/file/File.txt" > View files </a> Just click on the "View file" connection to see the string you just wrote!