Common methods for IO stream----File class

Package Com.qf.day18_3;import Java.io.file;import Java.io.filenamefilter;import java.io.ioexception;import java.util.date;/** * File class * * @author WGY * */public class Demo1 {public static void main (string[] args) throws Excepti on {//separator ();//Fileconstructor ();//fileope ();//rename ();d irectoryope ();//rename2 ();//listfiles ();} Delimiter public static void separator () {//Path delimiter System.out.println (file.pathseparator); System.out.println (File.pathseparatorchar);//Name Separator System.out.println (file.separator); System.out.println (File.separatorchar);} File construction method public static void Fileconstructor () {//Create file Object File MyFile = new file ("D:\\image\\haha.jpg"); File MyFile2 = new file ("D:\\image", "4.jpg"); File parent = new file ("D:\\image"); File MyFile3 = new file (parent, "4.jpg"); File MyFile4 = new file (parent, "haha.jpg"); File MyFile5 = new file ("D:\\xxx\\yyy\\a.jpg"); System.out.println (MyFile); System.out.println (MyFile2); System.out.println (myFile5);} /** * File Operation create delete judge get rename */public static void filEope () throws Exception {//Create file object absolute path relative path File File = new file ("D:\\a.txt");//1 Create (if file does not exist, create returns True if present, do not create, return false ) Boolean B = File.createnewfile (); System.out.println ("Create file" + b);//2 delete//2.1 Directly Delete Boolean b2=file.delete ();//System.out.println ("delete file" +b2);//2.2JVM Delete ( No direct deletion when the JVM exits)//File.deleteonexit ();//Thread.Sleep (5000);//3 Judging System.out.println ("CanExecute ()" + File.canexecute ());//Whether SYSTEM.OUT.PRINTLN can be executed ("CanRead ()" + file.canread ());//Whether it is readable System.out.println ("CanWrite ()" + File.canwrite ());//Can write System.out.println ("exists ()" + file.exists ());//whether there is System.out.println ("Isabsolute ()" + File.isabsolute ());//is the absolute path System.out.println ("Isfile ()" + file.isfile ()), or whether it is a file System.out.println ("Ishidden () "+ File.ishidden ());//Whether it is hidden//4 Get System.out.println (File.getabsolutepath ()); Gets the absolute path name//String System.out.println (File.getabsolutefile ()); Gets the absolute file name return type FILESYSTEM.OUT.PRINTLN (File.getcanonicalpath ());//Gets the canonical absolute path name System.out.println (File.getname ()); Get file name System.out.println(File.getpath ()); Gets the path System.out.println (new Date (file.lastmodified ())). toLocaleString ());//File Last Modified date System.out.println ( File.length ()); File Length}/** * file renamed */public static void rename () {file File=new file ("D:\\a.txt");  File Newfile=new file ("D:\\mywork\\b.txt"); File.renameto (newFile);//Modify Name}/** * Folder operation create delete judgment get rename */public static void Directoryope () {//Create Filefile dir=new File ("d:\\xxx\\yyy\\zzz");//1 create//boolean B=dir.mkdir ();//Create First-level folder Boolean b2= Dir.mkdirs ();//Create Multilevel folder System.out.println (B2);//2 Delete//2.1 Direct Delete (only one level can be deleted, only the empty directory)//boolean b3=dir.delete ();// SYSTEM.OUT.PRINTLN (b3);//2.2JVM delete//dir.deleteonexit ();//3 judge System.out.println ("exists ()" +dir.exists ()); Whether there is a System.out.println ("Isabsolute ()" +dir.isabsolute ());//is an absolute path System.out.println ("Isdirectory ()" + Dir.isdirectory ());//Is the directory System.out.println ("Ishidden ()" +dir.ishidden ()), or whether it is a hidden//4 get System.out.println (" GetAbsolutePath "+dir.getabsolutepath ()); Gets the absolute path System.out.println ("GetName ()" +dir.getname ()); System.out.println ("GetPath ()" +dir.GetPath ());//system.out.println ("LastModified" +dir.lastmodified ());//}/** * folder renamed */public static void Rename2 () { File Dir=new file ("d:\\xxx\\yyy\\zzz"); File Newdir=new file ("D:\\xxx\\yyy\\hahah");d Ir.renameto (newdir);} /** * Lists the files and sub-files under the folder */public static void Listfiles () {//1 Lists all file Dir=new file ("D:\\image");//string[] Files=dir.list ( );//for (string string:files) {//system.out.println (string);//}//2 filter File string[] files2=dir.list (New FilenameFilter () {public Boolean accept (File dir, String name) {//TODO auto-generated method Stubif (Name.endswith (". png")) {return true;} return false;}}); for (string string:files2) {System.out.println (string);}}}

file recursively deletes all content in a folder

Import Java.io.file;public class Demo4 {public static void main (string[] args) {//TODO auto-generated method Stubdeldir (n EW File ("d:\\xxx"));} public static void Deldir (file dir) {file[] files = dir.listfiles (), if (Files!=null) {for (file file:files) {if (File.isdir Ectory ()) {deldir (file);} else {System.out.println (file.tostring () +file.delete ());//delete file}}system.out.println (dir.tostring () +dir.delete ()) ;//Delete directory}}}

File class recursively traverse folder

Level is used to record the current recursive hierarchy public static void Listchilds (File F, int. level) {    //Generate layered spaces    stringbuffer sb = new Stringbuf Fer ("|--");    for (int i = 0; I < level; i++) {        sb.insert (0, "|  ");    }    file[] Childs = F.listfiles ();    Recursive exit    int length = Childs = = null? 0:childs.length;    for (int i = 0; i < length; i++) {        System.out.println (sb.tostring () + childs[i].getname ());        if (Childs[i].isdirectory ()) {            listchilds (Childs[i], level + 1);}}}    

Common methods for IO stream----File class