The file class of Java

The file class is an abstract representation of files and directory names in Java. The file class can be used to create, delete, rename, get paths, create time, and so on, and is the only operation related to the file itself. Therefore, it is necessary to study the file class well.

main methods of use:1.public file (String pathname)----Construction of a document instance based on its path2.public Boolean CreateNewFile () throws IOException-----Create file3.public Boolean Delete ()----------Delete file4.public String getParent ()----------get the top-level path to the file5.public boolean isdirectory ()------Determine if the folder is not6.public boolean isfile ()------Determine if the file is not7.public string[]list ()------------lists the file names in the folder8.public file[] listfile ()------------list all file instances of a folder9.public boolean mkdir ()----------Create a folder10.public boolean renameto (file dest)-----files renamed (can understand moving files)11.public Long Length ()-------Return file size12.String getpath ()-----------path name string

Example code:

2. Package com;
6. Import Java.io.File;
8. Import java.io.IOException;
12. public class Test {
16. public static void Main (string[] args) {
20. File.separator is cross-platform, under Windows for D:\\1.txt,linux d:/1.txt
22. File File=new file ("D:" +file.separator+ "1.txt");
24. File does not exist
26. if (!file.exists ())
28. {
30. try {
32. if (File.createnewfile ())//Create File
34. System.out.println ("File creation succeeded");
36. } catch (IOException e) {
40. E.printstacktrace ();
42. }
44. }
46. Get the top-level path to the file
48. SYSTEM.OUT.PRINTLN ("Parent directory:" +file.getparent ());
50. Determine if it is a directory
52. System.out.println ("is directory:" +file.isdirectory ());
54. Determine if it is a file
56. System.out.println ("Whether it is a file:" +file.isfile ());
58. Get File size
60. SYSTEM.OUT.PRINTLN ("File Size:" +file.length ());
62. File path
64. System.out.println (File.getpath ());
68. Rename, when the return value is true. The equivalent of moving d:\\1.txt to l:\\kk22.php.
70. if (File.renameto (New file ("l:\\kk22.php")))
72. System.out.println ("renaming succeeded");
74. else {
76. System.out.println ("rename failed");
78. }
82. Point to renamed File
84. File=new File ("l:\\kk22.php");
86. if (File.delete ())
88. SYSTEM.OUT.PRINTLN ("File deletion succeeded");
92. --------------------------------------Catalog Demo
96. File=new File ("L:" +file.separator+ "javatest");
98. does not exist
100. if (!file.exists ())
102. {
104. File.mkdir ();//Create the Directory
106. }
108. Add files to this directory
110. String temp;
112. for (int i=0;i<4;i++)
114. {
116. Temp= "";
118. temp= "L:" +file.separator+ "javatest" +file.separator+i+ "TXT";
120. File Ok=new file (temp);
122. try {
124. Ok.createnewfile ();//Create the file
126. } catch (IOException e) {
128. TODO auto-generated Catch block
130. E.printstacktrace ();
132. }//
134. }
136. Get the file name under this directory
138. String[] Name=file.list ();
140. for (int i=0;i<4;i++)
142. System.out.println (Name[i]);
144. Get a file instance under this directory
146. File[] Files=file.listfiles ();
148. for (int i=0;i<4;i++)
150. System.out.println (Files[i].getpath ());
154. }
158. }

Copy CodeFile can only get the files path creation time and other information, as well as the creation and deletion of files, the contents of the file can not be obtained and modified. The Java IO Stream is required to obtain and modify the specific contents of the file. The IO-related operations are then explained.

The file class of Java