Android java file path

Files, Path

Paths

getFileName() — возвращает имя файла из пути;

getParent() — возвращает «родительскую» директорию по отношению к текущему пути (то есть ту директорию, которая находится выше по дереву каталогов);

getRoot() — возвращает «корневую» директорию; то есть ту, которая находится на вершине дерева каталогов;

startsWith() , endsWith() — проверяют, начинается/заканчивается ли путь с переданного пути:

Вывод в консоль:

testFile.txt
C:\Users\Username\Desktop
C:\
true
false

Обрати внимание на то, как работает метод endsWith() . Он проверяет, заканчивается ли текущий путь на переданный путь. Именно на путь, а не на набор символов.

Сравни результаты этих двух вызовов:

Вывод в консоль:

false
true

В метод endsWith() нужно передавать именно полноценный путь, а не просто набор символов: в противном случае результатом всегда будет false, даже если текущий путь действительно заканчивается такой последовательностью символов (как в случае с “estFile.txt” в примере выше).

Кроме того, в Path есть группа методов, которая упрощает работу с абсолютными (полными) и относительными путями.

boolean isAbsolute() — возвращает true, если текущий путь является абсолютным:

Вывод в консоль:

Path normalize() — «нормализует» текущий путь, удаляя из него ненужные элементы. Ты, возможно, знаешь, что в популярных операционных системах при обозначении путей часто используются символы “.” (“текущая директория”) и “..” (родительская директория). Например: “./Pictures/dog.jpg” обозначает, что в той директории, в которой мы сейчас находимся, есть папка Pictures, а в ней — файл “dog.jpg”

Так вот. Если в твоей программе появился путь, использующий “.” или “..”, метод normalize() позволит удалить их и получить путь, в котором они не будут содержаться:

Вывод в консоль:

C:\Users\Java\examples
C:\Users\examples

Path relativize() — вычисляет относительный путь между текущим и переданным путем.

Вывод в консоль:

Username\Desktop\testFile.txt

Полный список методов Path довольно велик. Найти их все ты сможешь в документации Oracle. Мы же перейдем к рассмотрению Files .

Files

С помощью метода filter() отбираем только те строки из файла, которые начинаются с «Как».

Проходимся по всем отобранным строкам с помощью метода map() и приводим каждую из них к UPPER CASE.

Объединяем все получившиеся строки в List с помощью метода collect() .

preVisitDirectory() — логика, которую надо выполнять перед входом в папку;

visitFileFailed() — что делать, если вход в файл невозможен (нет доступа, или другие причины);

postVisitDirectory() — логика, которую надо выполнять после захода в папку.

У нас такой логики нет, поэтому нам достаточно SimpleFileVisitor . Логика внутри метода visitFile() довольно проста: прочитать все строки из файла, проверить, есть ли в них нужное нам содержимое, и если есть — вывести абсолютный путь в консоль. Единственная строка, которая может вызвать у тебя затруднение — вот эта: На деле все просто. Здесь мы просто описываем что должна делать программа после того, как выполнен вход в файл, и все необходимые операции совершены. В нашем случае необходимо продолжать обход дерева, поэтому мы выбираем вариант CONTINUE . Но у нас, например, могла быть и другая задача: найти не все файлы, которые содержат «This is the file we need», а только один такой файл. После этого работу программы нужно завершить. В этом случае наш код выглядел бы точно так же, но вместо break; было бы: Что ж, давай запустим наш код и посмотрим, работает ли он. Вывод в консоль: Нужный файл обнаружен! C:\Users\Username\Desktop\testFolder\FileWeNeed1.txt Нужный файл обнаружен! C:\Users\Username\Desktop\testFolder\level1-a\level2-a-a\FileWeNeed2.txt Нужный файл обнаружен! C:\Users\Username\Desktop\testFolder\level1-b\level2-b-b\FileWeNeed3.txt Отлично, у нас все получилось! 🙂 Если тебе хочется узнать больше о walkFileTree() , рекомендую тебе вот эту статью. Также ты можешь выполнить небольшое задание — заменить SimpleFileVisitor на обычный FileVisitor , реализовать все 4 метода и придумать предназначение для этой программы. Например, можно написать программу, которая будет логировать все свои действия: выводить в консоль название файла или папки до/после входа в них. На этом все — до встречи! 🙂

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Get File Path From URI in Android JAVA

In Android when we pick an image, video, or any other type of file from the gallery, documents folder, or capture directly from the camera, we receive a URI object in intent. We have different ways to get a full file path from URI based on content providers. In this article, we will discuss how to get a file path from URI in Android for the coming files picked through Storage, Documents, as well as depending upon the _data field for the MediaStore and other file-based ContentProviders.

Following is the Java code if you are looking for Kotlin solution visit this Get Path From URI In Kotlin.

Utility Class to Get File Path From URI in Android

Create a file UriUtils.java and copy the following class in that file.

How to use UriUtils class

You might think that this class is too lengthy, but as mentioned above it handles all scenarios. It checks all android versions and the folders to what the Uri is appointing. It handles different types of content providers. There are different methods depending upon documents path, is it coming through downloads folder or media directory. It also checks is it picked through SECONDARY_STORAGE or EXTERNAL_STORAGE. Few other scenarios like Google Photos Uri, Google drive Uri are also handled properly. Just copy this class in your project as a utility class and rest will be handled by it.

That’s it. This is how to get file path from URI in Java Android.

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Android java file path

A Path represents a path that is hierarchical and composed of a sequence of directory and file name elements separated by a special separator or delimiter. A root component, that identifies a file system hierarchy, may also be present. The name element that is farthest from the root of the directory hierarchy is the name of a file or directory. The other name elements are directory names. A Path can represent a root, a root and a sequence of names, or simply one or more name elements. A Path is considered to be an empty path if it consists solely of one name element that is empty. Accessing a file using an empty path is equivalent to accessing the default directory of the file system. Path defines the getFileName , getParent , getRoot , and subpath methods to access the path components or a subsequence of its name elements.

In addition to accessing the components of a path, a Path also defines the resolve and resolveSibling methods to combine paths. The relativize method that can be used to construct a relative path between two paths. Paths can be compared , and tested against each other using the startsWith and endsWith methods.

This interface extends Watchable interface so that a directory located by a path can be registered with a WatchService and entries in the directory watched.

WARNING: This interface is only intended to be implemented by those developing custom file system implementations. Methods may be added to this interface in future releases.

Accessing Files

Paths may be used with the Files class to operate on files, directories, and other types of files. For example, suppose we want a BufferedReader to read text from a file » access.log «. The file is located in a directory » logs » relative to the current working directory and is UTF-8 encoded.

Interoperability

Paths associated with the default provider are generally interoperable with the java.io.File class. Paths created by other providers are unlikely to be interoperable with the abstract path names represented by java.io.File . The toPath method may be used to obtain a Path from the abstract path name represented by a java.io.File object. The resulting Path can be used to operate on the same file as the java.io.File object. In addition, the toFile method is useful to construct a File from the String representation of a Path .

Concurrency

Implementations of this interface are immutable and safe for use by multiple concurrent threads.

Method Summary

All Methods Instance Methods Abstract Methods

Modifier and Type	Method and Description
int	compareTo (Path other)

Methods inherited from interface java.lang.Iterable

Method Detail

getFileSystem

isAbsolute

An absolute path is complete in that it doesn’t need to be combined with other path information in order to locate a file.

getRoot

getFileName

getParent

The parent of this path object consists of this path’s root component, if any, and each element in the path except for the farthest from the root in the directory hierarchy. This method does not access the file system; the path or its parent may not exist. Furthermore, this method does not eliminate special names such as «.» and «..» that may be used in some implementations. On UNIX for example, the parent of » /a/b/c » is » /a/b «, and the parent of «x/y/. » is » x/y «. This method may be used with the normalize method, to eliminate redundant names, for cases where shell-like navigation is required.

If this path has one or more elements, and no root component, then this method is equivalent to evaluating the expression:

getNameCount

getName

The index parameter is the index of the name element to return. The element that is closest to the root in the directory hierarchy has index 0 . The element that is farthest from the root has index count -1 .

subpath

The beginIndex and endIndex parameters specify the subsequence of name elements. The name that is closest to the root in the directory hierarchy has index 0 . The name that is farthest from the root has index count -1 . The returned Path object has the name elements that begin at beginIndex and extend to the element at index endIndex-1 .

startsWith

This path starts with the given path if this path’s root component starts with the root component of the given path, and this path starts with the same name elements as the given path. If the given path has more name elements than this path then false is returned.

Whether or not the root component of this path starts with the root component of the given path is file system specific. If this path does not have a root component and the given path has a root component then this path does not start with the given path.

If the given path is associated with a different FileSystem to this path then false is returned.

startsWith

endsWith

If the given path has N elements, and no root component, and this path has N or more elements, then this path ends with the given path if the last N elements of each path, starting at the element farthest from the root, are equal.

If the given path has a root component then this path ends with the given path if the root component of this path ends with the root component of the given path, and the corresponding elements of both paths are equal. Whether or not the root component of this path ends with the root component of the given path is file system specific. If this path does not have a root component and the given path has a root component then this path does not end with the given path.

If the given path is associated with a different FileSystem to this path then false is returned.

endsWith

normalize

The precise definition of this method is implementation dependent but in general it derives from this path, a path that does not contain redundant name elements. In many file systems, the » . » and » .. » are special names used to indicate the current directory and parent directory. In such file systems all occurrences of » . » are considered redundant. If a » .. » is preceded by a non-» .. » name then both names are considered redundant (the process to identify such names is repeated until it is no longer applicable).

This method does not access the file system; the path may not locate a file that exists. Eliminating » .. » and a preceding name from a path may result in the path that locates a different file than the original path. This can arise when the preceding name is a symbolic link.

resolve

If the other parameter is an absolute path then this method trivially returns other . If other is an empty path then this method trivially returns this path. Otherwise this method considers this path to be a directory and resolves the given path against this path. In the simplest case, the given path does not have a root component, in which case this method joins the given path to this path and returns a resulting path that ends with the given path. Where the given path has a root component then resolution is highly implementation dependent and therefore unspecified.

resolve

resolveSibling

resolveSibling

relativize

Relativization is the inverse of resolution . This method attempts to construct a relative path that when resolved against this path, yields a path that locates the same file as the given path. For example, on UNIX, if this path is «/a/b» and the given path is «/a/b/c/d» then the resulting relative path would be «c/d» . Where this path and the given path do not have a root component, then a relative path can be constructed. A relative path cannot be constructed if only one of the paths have a root component. Where both paths have a root component then it is implementation dependent if a relative path can be constructed. If this path and the given path are equal then an empty path is returned.

For any two normalized paths p and q, where q does not have a root component,

When symbolic links are supported, then whether the resulting path, when resolved against this path, yields a path that can be used to locate the same file as other is implementation dependent. For example, if this path is «/a/b» and the given path is «/a/x» then the resulting relative path may be «../x» . If «b» is a symbolic link then is implementation dependent if «a/b/../x» would locate the same file as «/a/x» .

toUri

This method constructs an absolute URI with a scheme equal to the URI scheme that identifies the provider. The exact form of the scheme specific part is highly provider dependent.

In the case of the default provider, the URI is hierarchical with a path component that is absolute. The query and fragment components are undefined. Whether the authority component is defined or not is implementation dependent. There is no guarantee that the URI may be used to construct a java.io.File . In particular, if this path represents a Universal Naming Convention (UNC) path, then the UNC server name may be encoded in the authority component of the resulting URI. In the case of the default provider, and the file exists, and it can be determined that the file is a directory, then the resulting URI will end with a slash.

The default provider provides a similar round-trip guarantee to the File class. For a given Path p it is guaranteed that

When a file system is constructed to access the contents of a file as a file system then it is highly implementation specific if the returned URI represents the given path in the file system or it represents a compound URI that encodes the URI of the enclosing file system. A format for compound URIs is not defined in this release; such a scheme may be added in a future release.

toAbsolutePath

If this path is already absolute then this method simply returns this path. Otherwise, this method resolves the path in an implementation dependent manner, typically by resolving the path against a file system default directory. Depending on the implementation, this method may throw an I/O error if the file system is not accessible.

toRealPath

The precise definition of this method is implementation dependent but in general it derives from this path, an absolute path that locates the same file as this path, but with name elements that represent the actual name of the directories and the file. For example, where filename comparisons on a file system are case insensitive then the name elements represent the names in their actual case. Additionally, the resulting path has redundant name elements removed.

If this path is relative then its absolute path is first obtained, as if by invoking the toAbsolutePath method.

The options array may be used to indicate how symbolic links are handled. By default, symbolic links are resolved to their final target. If the option NOFOLLOW_LINKS is present then this method does not resolve symbolic links. Some implementations allow special names such as » .. » to refer to the parent directory. When deriving the real path, and a » .. » (or equivalent) is preceded by a non-» .. » name then an implementation will typically cause both names to be removed. When not resolving symbolic links and the preceding name is a symbolic link then the names are only removed if it guaranteed that the resulting path will locate the same file as this path.

toFile

If this path was created by invoking the File toPath method then there is no guarantee that the File object returned by this method is equal to the original File .

register

In this release, this path locates a directory that exists. The directory is registered with the watch service so that entries in the directory can be watched. The events parameter is the events to register and may contain the following events:

• ENTRY_CREATE — entry created or moved into the directory
• ENTRY_DELETE — entry deleted or moved out of the directory
• ENTRY_MODIFY — entry in directory was modified

The context for these events is the relative path between the directory located by this path, and the path that locates the directory entry that is created, deleted, or modified.

The set of events may include additional implementation specific event that are not defined by the enum StandardWatchEventKinds

The modifiers parameter specifies modifiers that qualify how the directory is registered. This release does not define any standard modifiers. It may contain implementation specific modifiers.

Where a file is registered with a watch service by means of a symbolic link then it is implementation specific if the watch continues to depend on the existence of the symbolic link after it is registered.

register

An invocation of this method behaves in exactly the same way as the invocation

Usage Example: Suppose we wish to register a directory for entry create, delete, and modify events:

iterator

The first element returned by the iterator represents the name element that is closest to the root in the directory hierarchy, the second element is the next closest, and so on. The last element returned is the name of the file or directory denoted by this path. The root component, if present, is not returned by the iterator.

compareTo

This method may not be used to compare paths that are associated with different file system providers.

equals

If the given object is not a Path, or is a Path associated with a different FileSystem , then this method returns false .

Whether or not two path are equal depends on the file system implementation. In some cases the paths are compared without regard to case, and others are case sensitive. This method does not access the file system and the file is not required to exist. Where required, the isSameFile method may be used to check if two paths locate the same file.

This method satisfies the general contract of the Object.equals method.

hashCode

The hash code is based upon the components of the path, and satisfies the general contract of the Object.hashCode method.

toString

If this path was created by converting a path string using the getPath method then the path string returned by this method may differ from the original String used to create the path.

The returned path string uses the default name separator to separate names in the path.

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