Java io Flow details (ii)

1 File objects

 Public classCreateFile { Public Static void Main(string[] args) {//Create a file path and name to manipulate        //Where file.separator represents a system-related delimiter, under Linux:/windows: \ \        //path represents the parent directory in this program, does not contain sub-filesString Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent";//childpath represents subdirectories within this program, including sub-filesString Childpath ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\demo.txt";//Constructs a file object in a separate way from parent directory and sub-file        //can also be written as New File ("D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent", "test.txt");File F1 =NewFile (Path,"Test.txt");//Use absolute path to construct file object        //can also be written as New File ("D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\demo.txt");File F2 =NewFile (Childpath);//Create a file object for parent directoryFile parent =NewFile (path);//Building a new file object with existing parent directory objects and sub-filesFile F3 =NewFile (Parent,"Hello.txt"); System. out. println ("The path of F1 ="+ F1); System. out. println ("The path of F2 ="+ F2); System. out. println ("The Path of F3 ="+ F3); }}

Result diagram

It's worth noting that the code just created the object and didn't generate the file!!


After running the code, there are no folders and files that generate a response under that folder.

2 Creating files and deleting files

 Public classCreatefileanddelete { Public Static void Main(string[] args) {String Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent"; File f =NewFile (Path);Try{/* Because creating and deleting files involves underlying operations, it is possible to throw an exception */            //Returns TRUE if the creation is successful            //If the file already exists, the creation is unsuccessful, return flase, do not think it will overwriteSystem. out. println ("Create file:"+ F.createnewfile ());//delete file, return true successfully, otherwise return flaseSystem. out. println ("Delete file:"+ F.delete ());//This method means that the file is deleted when the virtual machine exits            //Reason: The program is running with the possibility of an exception resulting in a direct exit            //cleaning residue is necessary ~! F.deleteonexit (); }Catch(IOException e)        {E.printstacktrace (); }      }}

Results

3 File Judgments and tests

 Public classfiletest { Public Static void Main(string[] args) {String Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent"; File f =NewFile (Path);//Determine if the file can be executedSystem. out. println ("F is executable:"+ F.canexecute ());//Determine if the file existsSystem. out. println ("F is present:"+ f.exists ());//Determine if the file is readableSystem. out. println ("F is readable:"+ F.canread ());//Determine if the file is writableSystem. out. println ("F can be written:"+ F.canwrite ());//Determine if the file is an absolute path nameSystem. out. println ("F is absolute path:"+ F.isabsolute ());//Determine if the file is a standard fileSystem. out. println ("F is a standard file:"+ F.isfile ());//Determine if the file is a directorySystem. out. println ("F is directory:"+ f.isdirectory ());//Determine if the file is hiddenSystem. out. println ("F is hidden:"+ F.ishidden ()); } }

Results if the parent folder does not exist

Results in the presence of the parent folder

4 Creating a Folder

public   Class  Createfilepath {public  static  Span class= "Hljs-keyword" >void  main  (string[] args) {String path =  "D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent" ;        //path here as the parent directory exists         File F1 = new  File (path, "/ABC" );        File F2 = new  File (path, "/d/e/f/g" );        //Create a directory  System.        out . println (F1.mkdir ());        //recursively create a directory  System.    out . println (F2.mkdirs ()); } }

Result diagram before running code

Result diagram after running code

Console output is

5 Getting file information

 Public classGetFileInfo { Public Static void Main(string[] args) {String Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent"; File f =NewFile (path);//Returns the absolute path of the file            //return value here is StringSystem. out. println ("F's Absolute path name:"+ F.getabsolutepath ());//Returns the absolute path of the file            //Return value here is fileSystem. out. println ("F's Absolute Path object:"+ F.getabsolutefile ());//Returns the name of the file or directorySystem. out. println ("F's name:"+ F.getname ());//Returns the relative path of the file            ////What path is encapsulated in the constructor and what path is returnedSystem. out. println ("F's Path:"+ F.getpath ());//Returns the path to the parent directory            //If the path in the constructor is not an absolute path, NULL is returned hereSystem. out. println ("F's parent directory:"+ f.getparent ()); }}

Result diagram

Console output Information:

6 listing the root directory of the file system

publicclass GetRootPath {    publicstaticvoidmain(String[] args) {        //listRoots()是一个静态方法，返回文件数组        File[] files = File.listRoots();        //foreach循环打印File对象        for (File x : files) {            System.out.println(x);        }    }}

Results

7 List all files and directories under the file

 Public classGetfilechildfile { Public Static void Main(string[] args) {String Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent"; File f =NewFile (path);//Mode one: List ()            //Returns an array of strings containing all filenames under the specified directory            //If it is not a directory, returns nullstring[] files = f.list (); for(String x:files) {System. out. println (x); }//Way Two: Listfiles ()            //Returns the file array            /* file[] files = f.listfiles ();            for (File x:files) {//If you need to include a path, print x directly System.out.println (X.getname ()); }            */}}

Result diagram:

8 recursively lists all files in the directory

 Public classGetallchilefile { Public Static void Main(string[] args) {String Path ="D:\\Program Files (x86) \\ADT\\workspace\\JavaIO\\parent"; File f =NewFile (path);//Call the following recursive methodPrint (f); }//Print a list of directories in a recursive manner         Public Static void Print(File f) {if(F.isdirectory ()) {file[] files = f.listfiles (); for(File x:files)                {print (x); }            }Else{System. out. println (f); }        }}

Results

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Java io Flow details (ii)