Java IO Learning Note: File class

in the entire IO package, the only class that represents the file itself is the files class. You can use the file class to make 1 common operations such as creating or deleting files. You want to use the file class. The first thing to do is to observe the method of constructing the file class, which is commonly constructed as follows: When the public file (String pathname) instantiates the file class, the path must be set .

No.	Method or constant	Type	Describe
1	public static final String PathSeparator	Constant	Represents the delimiter for the path (Windows is ";" ）
2	public static final String separator	Constant	Represents the delimiter for the path (Windows is "\")
3	Public File (String pathname)	Structure	Creating a File class object, passing in the full path
4	public Boolean CreateNewFile () throws IOException	Ordinary	Create a new file
5	public Boolean Delete ()	Ordinary	deleting files
6	public Boolean exists ()	Ordinary	Determine if a file exists
7	public boolean isdirectory ()	Ordinary	Determines whether a given path is in a directory
8	public long Length ()	Ordinary	Returns the size of a file
9	Public string[] List ()	Ordinary	Lists the entire contents of the specified directory, just the name
10	Public file[] Listfiles ()	Ordinary	List all contents of the specified directory, there will be paths
11	Public Boolean mkdir ()	Ordinary	Create a Directory
12	Public Boolean Renameto (File dest)	Ordinary	Renaming an existing file

Instance Action one: Create a new file Create a Test.txt file on the D drive

Import Java.io.file;import Java.io.ioexception;public class Test1 {public    static void Main (string[] args) {        File F=new file ("D:" +file.separator+ "test.txt");//For increased portability, we recommend using File.separator        try {            f.createnewfile ();        } catch (IOException e) {            e.printstacktrace ();}}    }

instance Operation two: delete a specified file delete the Test.txt file just created

Import Java.io.file;public class Test2 {public    static void Main (string[] args) {        file F=new file ("D:" +file.sep arator+ "Test.txt");        if (f.exists ()) {//To determine that the file does not exist, do not delete the            f.delete () if it does not exist;}}}    

　　

　　 instance Operation three: synthetic create, delete file operation given a path, if this file exists, then delete, if not present, create

Import Java.io.file;import Java.io.ioexception;public class Test3 {public    static void Main (string[] args) {        File F=new file ("D:" +file.separator+ "test.txt");        if (f.exists ()) {            f.delete ();        } else{            try {                f.createnewfile ();            } catch (IOException e) {                e.printstacktrace ();    }}}}

　　 instance Operation four: Create a folder use the MkDir () method to create a folder

Import Java.io.file;public class Test4 {public    static void Main (string[] args) {        file F=new file ("D:" +file.sep arator+ "test");        F.mkdir ();//Create Folder    }}

　　 instance Action five: List all files for a specified directory if you now have a directory, you can list the contents of the directory directly. However, there are two methods listed in the File class:

• Returned as an array of strings: public string[] List ()
• Returned as a File array: public file[] Listfiles ()

Action One: List all content using list ()

Import Java.io.file;public class Test5 {public    static void Main (string[] args) {        file F=new file ("D:" +file.separ Ator);        String[] Str=f.list ();        for (String s:str) {            System.out.println (s);}}    }

　　 all names are listed above, including the name of the folder and the name of the file. action Two: Use Listfiles () to list

Import Java.io.file;public class Test6 {public    static void Main (string[] args) {        file F=new file ("D:" +file.separ Ator);        File[] Files=f.listfiles ();        for (file file:files) {            System.out.println (file);}}    }

　　 the full path is listed above. Instance Operation VI: Determine whether a given path is a directory given path, determine whether it is a directory

Import Java.io.file;public class Test7 {public    static void Main (string[] args) {        file F=new file ("D:" +file.sep Arator);        if (F.isdirectory ()) {            System.out.println (F.getpath () + "is Directory");        } else{            System.out.println (F.getpath () + "not Directory");}}}    

Java IO Learning Note: File class