File et pile en java

Computer Organization. Discrete Mathematics. Ethical Hacking. Computer Graphics. Software Engineering. Web Technology. Cyber Security. C Programming. Control System. Data Mining. Data Warehouse. Javatpoint Services JavaTpoint offers too many high quality services. On constate que le code est bien plus simple que dans le cas des tableaux figure 2. Le package java. Nous nous focalisons sur la classe LinkedList.

Figure 2. Exercice 2. In the try block, we call the createNewFile method through the f0 object to create a new file in the specified location.

If the method returns false, it will jump to the else section. If there is any error, it gets handled in the catch block. The operation is performed to get the file information. We use several methods to get the information about the file like name, absolute path, is readable, is writable and length. In the above code, we import the java. File package and create a class FileInfo. In the main method, we create an object of the text file which we have created in our previous example.

We check the existence of the file using a conditional statement, and if it is present, we get the following information about that file:. The next operation which we can perform on a file is "writing into a file". In order to write data into a file, we will use the FileWriter class and its write method together. We need to close the stream using the close method to retrieve the allocated resources.

FileWriter and java. IOException classes. We create a class WriteToFile, and in its main method, we use the try-catch block. In the try section, we create an instance of the FileWriter class, i. We call the write method of the FileWriter class and pass the content to that function which we want to write. After that, we call the close method of the FileWriter class to close the file stream.

After writing the content and closing the stream, we print a custom message. If we get any error in the try section, it jumps to the catch block.

In the catch block, we handle the IOException and print a custom message. The next operation which we can perform on a file is "read from a file". In order to write data into a file, we will use the Scanner class. Here, we need to close the stream using the close method. We will create an instance of the Scanner class and use the hasNextLine method nextLine method to get data from the file.

In the above code, we import the "java. This is useful for error reporting and to diagnose why a file cannot be deleted. Returns: true if and only if the file or directory is successfully deleted; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager. String method denies delete access to the file deleteOnExit public void deleteOnExit Requests that the file or directory denoted by this abstract pathname be deleted when the virtual machine terminates.

Files or directories are deleted in the reverse order that they are registered. Invoking this method to delete a file or directory that is already registered for deletion has no effect.

Deletion will be attempted only for normal termination of the virtual machine, as defined by the Java Language Specification. Once deletion has been requested, it is not possible to cancel the request. This method should therefore be used with care. String method denies delete access to the file Since: 1.

If this abstract pathname does not denote a directory, then this method returns null. Otherwise an array of strings is returned, one for each file or directory in the directory.

Names denoting the directory itself and the directory's parent directory are not included in the result. Each string is a file name rather than a complete path. There is no guarantee that the name strings in the resulting array will appear in any specific order; they are not, in particular, guaranteed to appear in alphabetical order. Note that the Files class defines the newDirectoryStream method to open a directory and iterate over the names of the files in the directory.

This may use less resources when working with very large directories, and may be more responsive when working with remote directories.

Returns: An array of strings naming the files and directories in the directory denoted by this abstract pathname. The array will be empty if the directory is empty. The behavior of this method is the same as that of the list method, except that the strings in the returned array must satisfy the filter.

If the given filter is null then all names are accepted. Otherwise, a name satisfies the filter if and only if the value true results when the FilenameFilter. Parameters: filter - A filename filter Returns: An array of strings naming the files and directories in the directory denoted by this abstract pathname that were accepted by the given filter.

The array will be empty if the directory is empty or if no names were accepted by the filter. Otherwise an array of File objects is returned, one for each file or directory in the directory. Pathnames denoting the directory itself and the directory's parent directory are not included in the result. Each resulting abstract pathname is constructed from this abstract pathname using the File File, String constructor.

Therefore if this pathname is absolute then each resulting pathname is absolute; if this pathname is relative then each resulting pathname will be relative to the same directory. This may use less resources when working with very large directories. Returns: An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. The behavior of this method is the same as that of the listFiles method, except that the pathnames in the returned array must satisfy the filter.

If the given filter is null then all pathnames are accepted. Otherwise, a pathname satisfies the filter if and only if the value true results when the FilenameFilter.

Parameters: filter - A filename filter Returns: An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. Otherwise, a pathname satisfies the filter if and only if the value true results when the FileFilter.

Parameters: filter - A file filter Returns: An array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname. Filter mkdir public boolean mkdir Creates the directory named by this abstract pathname. Returns: true if and only if the directory was created; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager. String method does not permit the named directory to be created mkdirs public boolean mkdirs Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories.

Note that if this operation fails it may have succeeded in creating some of the necessary parent directories. Returns: true if and only if the directory was created, along with all necessary parent directories; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager. String method does not permit verification of the existence of the named directory and all necessary parent directories; or if the SecurityManager.

String method does not permit the named directory and all necessary parent directories to be created renameTo public boolean renameTo File dest Renames the file denoted by this abstract pathname. Many aspects of the behavior of this method are inherently platform-dependent: The rename operation might not be able to move a file from one filesystem to another, it might not be atomic, and it might not succeed if a file with the destination abstract pathname already exists. The return value should always be checked to make sure that the rename operation was successful.

Note that the Files class defines the move method to move or rename a file in a platform independent manner. Parameters: dest - The new abstract pathname for the named file Returns: true if and only if the renaming succeeded; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager.

String method denies write access to either the old or new pathnames NullPointerException - If parameter dest is null setLastModified public boolean setLastModified long time Sets the last-modified time of the file or directory named by this abstract pathname. All platforms support file-modification times to the nearest second, but some provide more precision. The argument will be truncated to fit the supported precision. If the operation succeeds and no intervening operations on the file take place, then the next invocation of the lastModified method will return the possibly truncated time argument that was passed to this method.

Parameters: time - The new last-modified time, measured in milliseconds since the epoch GMT, January 1, Returns: true if and only if the operation succeeded; false otherwise Throws: IllegalArgumentException - If the argument is negative SecurityException - If a security manager exists and its SecurityManager. String method denies write access to the named file Since: 1. After invoking this method the file or directory is guaranteed not to change until it is either deleted or marked to allow write access.

Whether or not a read-only file or directory may be deleted depends upon the underlying system. Returns: true if and only if the operation succeeded; false otherwise Throws: SecurityException - If a security manager exists and its SecurityManager. The Files class defines methods that operate on file attributes including file permissions.

This may be used when finer manipulation of file permissions is required. Parameters: writable - If true , sets the access permission to allow write operations; if false to disallow write operations ownerOnly - If true , the write permission applies only to the owner's write permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's write permission from that of others, then the permission will apply to everybody, regardless of this value.

Returns: true if and only if the operation succeeded. The operation will fail if the user does not have permission to change the access permissions of this abstract pathname.

An invocation of this method of the form file. Parameters: readable - If true , sets the access permission to allow read operations; if false to disallow read operations ownerOnly - If true , the read permission applies only to the owner's read permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's read permission from that of others, then the permission will apply to everybody, regardless of this value.

If readable is false and the underlying file system does not implement a read permission, then the operation will fail. Parameters: executable - If true , sets the access permission to allow execute operations; if false to disallow execute operations ownerOnly - If true , the execute permission applies only to the owner's execute permission; otherwise, it applies to everybody. If the underlying file system can not distinguish the owner's execute permission from that of others, then the permission will apply to everybody, regardless of this value.

If executable is false and the underlying file system does not implement an execute permission, then the operation will fail. If executable is false and the underlying file system does not implement an excute permission, then the operation will fail. Returns: true if and only if the abstract pathname exists and the application is allowed to execute the file Throws: SecurityException - If a security manager exists and its SecurityManager.

String method denies execute access to the file Since: 1. A particular Java platform may support zero or more hierarchically-organized file systems. Each file system has a root directory from which all other files in that file system can be reached. The set of available filesystem roots is affected by various system-level operations such as the insertion or ejection of removable media and the disconnecting or unmounting of physical or virtual disk drives.

This method returns an array of File objects that denote the root directories of the available filesystem roots. It is guaranteed that the canonical pathname of any file physically present on the local machine will begin with one of the roots returned by this method. The canonical pathname of a file that resides on some other machine and is accessed via a remote-filesystem protocol such as SMB or NFS may or may not begin with one of the roots returned by this method.

If the pathname of a remote file is syntactically indistinguishable from the pathname of a local file then it will begin with one of the roots returned by this method. Thus, for example, File objects denoting the root directories of the mapped network drives of a Windows platform will be returned by this method, while File objects containing UNC pathnames will not be returned by this method. Unlike most methods in this class, this method does not throw security exceptions.

If a security manager exists and its SecurityManager. Returns: An array of File objects denoting the available filesystem roots, or null if the set of roots could not be determined. The array will be empty if there are no filesystem roots. Returns: The size, in bytes, of the partition or 0L if this abstract pathname does not name a partition Throws: SecurityException - If a security manager has been installed and it denies RuntimePermission "getFileSystemAttributes" or its SecurityManager.