Java file operation

xiaoxiao2021-03-06  117

File establishment / check and delete <% @ page contentty = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%> file Establish, check and delete </ title> </ head> <body> <% string path = request.getRealPath (""); // out.println (path); file f = new file (path, "file.txt "); // out.println (f); // out.println (f.exists ());</p> <p>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}%></p> <p>Catalog / Check and Delete <% @ Page ContentType = "Text / HTML; Charset = GB2312"%> <% @ Page Import = "Java.io. *"%> <HTML> <head> <title> directory Establish / Check and Delete </ Title> </ head> <body> <% 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></p> <p>How to handle virtual directory <% @ Page ContentType = "text = GB2312"%> <page import = "java.io. *"%> Java.io. * "%> JSP in JSP How to deal with virtual directory </ title> </ head> <body> acquired a virtual directory corresponding to disk path <br> WEB site main directory location is <font color = # ff0000> <% = request.getRealPath ("/") directory location%> </ font> <br> JSP page where the <font color = # ff0000> <% = request.getRealPath ( "./")%></ font> on <br> JSP pages directory level The location of the directory <font color = # ff0000> <% = Request.getRealPath ("../" )% (" "<br> </ body> </ html></p> <p>Number of file properties <% @ Page ContentType = "Text / HTML; Charset = GB2312"%> <% @ page import = "java.util.date, java.io. *"%> <Html> <head> <Title > File attributes </ Title> </ head> <body> <% string path = request.getRealPath ("/"); file f = new file (path, "readdata.txt"); if (F.Exists ()) {%> <% = f.getName ()%> following properties: <br> <br> file length is:? <% = f.length ()%> <% = f.isFile () " Is the file ":" Not the file "%> <br> <% = f.Indirectory ()?" Is a directory ":" Not a directory "%> <br> <% = f.canread ()?" Readable " : "Do not read"%> <br> <% = f.canwrite ()? "Writable": "Not writable"%> <br> <% = f.ishidden ()? "Is a hidden file" : "Not hidden file"%> <br> File's last modification date is: <% = new date (f.lastmodified ())%> <br> <%} else {f.createNewFile (); // is currently establishment of a directory file named ReaData.txt%> <% = f.getName ()%> following properties: <br> <br> file length is: <% = f.length ()%> <% = f.isfile ()? "Yes File": "Not File"%> <br> <% = f.IsDirectory ()? "is a directory": "Not a directory"%> <br> <% = f.canread "Readable": "Do not read"%> <br> <% = f.canwrite ()? "Write": "Not Write"%> <br> <% = f.ishidden )? "It is hidden file": "Not hidden file"%> <br> File's last modification date is: <% = new date (f.lastmodified ())%> <br> <%}%> </ body > </ html></p> <p>Take out the file in the directory <% @ Page ContentType = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%> <Html> <head> <title> Take out the directory File method - list files in the directory </ title> </ head> <body> <% 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 ("<font color = # ff0000> path " directory in the directory: </ font> <br> "); for (int i = 0; i <list.Length; i ) {if (list [i] .isfile ()) {out.println (List [i] .GetName () "<br>");}}}} Out.println ("<br> <font color = # ff0000>" "directory in the directory: </ font> <br>"); for (int i = 0; i <list.Length; i ) {if (list [i] .Indirectory ()) {out.println (list [i] .getname () "<br>");}}%> </ body > </ html> Judging whether it is blank file <% @ Page ContentType = "text / html; charset = GB2312"%> <% @ page import = "java.io. *"%> <html> <head> <Title > Judgment is a blank file </ title> </ head> <body> <% 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 <br>" in atend.txt file ");} else {Out.println (" Atend Data in .txt file ");} fr.close ();%> </ body> </ html></p> <p>Read all file data <% @ Page ContentType = "text / html; charSet = GB2312"%> <% @ page import = "java.io. *, Java.lang. *"%> <Html> <head> <title> Read all file data </ ​​title> </ head> <body> <% 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 ("<br>"); // 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. *"%> <Html> <head> <title> file reading </ title > </ head> <body> <% 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 "<br>"); / / 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></p> <p>Broken characters in the file do not read <% @ page contentty = "text / html; charSet = GB2312"%> <% @ page import = "java.io. *"%> <Html> <head> <title> Slightly not reading </ title> </ head> <body> <% 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. *"%> <html> <head> <title> Write data </ ​​title> </ head> <body> <% 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 ();</p> <p>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>"); br.close (); // Close BufferedReader object fr.close ();%> </ body> </ html></p> <p><% @ Page contentty = "text / html; charset = GB2312"%> <@ page import = "java.io. *"%> <Html> <head> <title> will write Data Branch of the file </ title> </ head> <body> <% 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: <br>"); 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 "<br>"); line = br.readline ();} fr.close ();%> < / Body> </ html></p></div><div class="text-center mt-3 text-grey"> 转载请注明原文地址:https://www.9cbs.com/read-126377.html</div><div class="plugin d-flex justify-content-center mt-3"></div><hr><div class="row"><div class="col-lg-12 text-muted mt-2"><i class="icon-tags mr-2"></i><span class="badge border border-secondary mr-2"><h2 class="h6 mb-0 small"><a class="text-secondary" href="tag-2.html">9cbs</a></h2></span></div></div></div></div><div class="card card-postlist border-white shadow"><div class="card-body"><div class="card-title"><div class="d-flex justify-content-between"><div><b>New Post</b>(<span class="posts">0</span>) </div><div></div></div></div><ul class="postlist list-unstyled"> </ul></div></div><div class="d-none threadlist"><input type="checkbox" name="modtid" value="126377" checked /></div></div></div></div></div><footer class="text-muted small bg-dark py-4 mt-3" id="footer"><div class="container"><div class="row"><div class="col">CopyRight © 2020 All Rights Reserved </div><div class="col text-right">Processed: <b>0.042</b>, SQL: <b>9</b></div></div></div></footer><script src="./lang/en-us/lang.js?2.2.0"></script><script src="view/js/jquery.min.js?2.2.0"></script><script src="view/js/popper.min.js?2.2.0"></script><script src="view/js/bootstrap.min.js?2.2.0"></script><script src="view/js/xiuno.js?2.2.0"></script><script src="view/js/bootstrap-plugin.js?2.2.0"></script><script src="view/js/async.min.js?2.2.0"></script><script src="view/js/form.js?2.2.0"></script><script> var debug = DEBUG = 0; var url_rewrite_on = 1; var url_path = './'; var forumarr = {"1":"Tech"}; var fid = 1; var uid = 0; var gid = 0; xn.options.water_image_url = 'view/img/water-small.png'; </script><script src="view/js/wellcms.js?2.2.0"></script><a class="scroll-to-top rounded" href="javascript:void(0);"><i class="icon-angle-up"></i></a><a class="scroll-to-bottom rounded" href="javascript:void(0);" style="display: inline;"><i class="icon-angle-down"></i></a></body></html><script> var forum_url = 'list-1.html'; var safe_token = 'J_2FQNCwQLq5X_2BJOZJfJHU93FRW1gHXggo_2FsheMJ40y2VpAoXaIu1RXqIgvhbd9JzbNGKHyqruWVEfSJTgus97_2BQ_3D_3D'; var body = $('body'); body.on('submit', '#form', function() { var jthis = $(this); var jsubmit = jthis.find('#submit'); jthis.reset(); jsubmit.button('loading'); var postdata = jthis.serializeObject(); $.xpost(jthis.attr('action'), postdata, function(code, message) { if(code == 0) { location.reload(); } else { $.alert(message); jsubmit.button('reset'); } }); return false; }); function resize_image() { var jmessagelist = $('div.message'); var first_width = jmessagelist.width(); jmessagelist.each(function() { var jdiv = $(this); var maxwidth = jdiv.attr('isfirst') ? first_width : jdiv.width(); var jmessage_width = Math.min(jdiv.width(), maxwidth); jdiv.find('img, embed, iframe, video').each(function() { var jimg = $(this); var img_width = this.org_width; var img_height = this.org_height; if(!img_width) { var img_width = jimg.attr('width'); var img_height = jimg.attr('height'); this.org_width = img_width; this.org_height = img_height; } if(img_width > jmessage_width) { if(this.tagName == 'IMG') { jimg.width(jmessage_width); jimg.css('height', 'auto'); jimg.css('cursor', 'pointer'); jimg.on('click', function() { }); } else { jimg.width(jmessage_width); var height = (img_height / img_width) * jimg.width(); jimg.height(height); } } }); }); } function resize_table() { $('div.message').each(function() { var jdiv = $(this); jdiv.find('table').addClass('table').wrap('<div class="table-responsive"></div>'); }); } $(function() { resize_image(); resize_table(); $(window).on('resize', resize_image); }); var jmessage = $('#message'); jmessage.on('focus', function() {if(jmessage.t) { clearTimeout(jmessage.t); jmessage.t = null; } jmessage.css('height', '6rem'); }); jmessage.on('blur', function() {jmessage.t = setTimeout(function() { jmessage.css('height', '2.5rem');}, 1000); }); $('#nav li[data-active="fid-1"]').addClass('active'); </script>