Files-Paths

Paths类：创建路径Path

(1)创建本地路径：

static Path

get(String first, String... more)

（2）创建网络URL路径：

 

static Path

get(URI uri)

Path类：

（1）为某一个Path注册事件管理器WatchService，然后获得事件集合WatchKey，之后就可以获取具体事件的信息了。

 

WatchKey

register(WatchService watcher, WatchEvent.Kind<?>... events) Registers the file located by this path with a watch service.

例子：

WatchService watchService = FileSystems.getDefault().newWatchService();
Paths.get("").register(watchService,StandardWatchEventKinds.ENTRY_CREATE,
        StandardWatchEventKinds.ENTRY_DELETE,StandardWatchEventKinds.ENTRY_MODIFY,
        StandardWatchEventKinds.OVERFLOW);
while (true){
    WatchKey key = watchService.take();
    for (WatchEvent event : key.pollEvents()){
        WatchEvent.Kind kind= event.kind();
        event.context();
    }
    
}

（2）比较path路径的信息

boolean

endsWith(Path other)

boolean

startsWith(Path other)

int	compareTo(Path other)

（3）绝对路径、父路径等参数信息

 

Files类：

（1）遍历文件

 

static Path

walkFileTree(Path start, FileVisitor<? super Path> visitor) Walks a file tree.

FileVistor的直接子接口SimpleFileVisitor，SimpleFileVisitor提供了默认是实现，也就是说abstract方法可以override部分。

 

Path path1 = Files.walkFileTree(Paths.get("."), new SimpleFileVisitor<Path>() {
    @Override
    public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
        System.out.println("正在访问：" + file);
        if (file.startsWith("Sorting")) {
            System.out.println("找到了");
            return FileVisitResult.TERMINATE;
        } else
            return FileVisitResult.CONTINUE;
    }

    @Override
    public FileVisitResult postVisitDirectory(Path dir, IOException exc) throws IOException {
        System.out.println("正在访问文件：" + dir);
        return FileVisitResult.CONTINUE;
    }
});

（2）找到符合规则的path

static Stream<Path>

find(Path start, int maxDepth,BiPredicate<Path,BasicFileAttributes> matcher,FileVisitOption... options)

Interface BasicFileAttributes 

         All Known Subinterfaces:DosFileAttributes, PosixFileAttributes

 

static <V extends FileAttributeView> V

getFileAttributeView(Path path, Class<V> type,LinkOption... options)

（3）文件属性视图

--AttributeView

        --FileAttributeView

                    --AclFileAttributeView

                    --BasicFileAttributeView

                    --FileOwnerFileAttributeView

                    --PosixFileAttributeView

例子：

BasicFileAttributeView b = Files.getFileAttributeView(path, BasicFileAttributeView.class);
BasicFileAttributes attrs = b.readAttributes();

（4）直接将路径映射成输入流或输出流

static InputStream	newInputStream(Path path,OpenOption... options) Opens a file, returning an input stream to read from the file.
static OutputStream	newOutputStream(Path path,OpenOption... options) Opens or creates a file, returning an output stream that may be used to write bytes to the file.

 

static BufferedReader	newBufferedReader(Path path) Opens a file for reading, returning a BufferedReader to read text from the file in an efficient manner.
static BufferedReader	newBufferedReader(Path path, Charset cs) Opens a file for reading, returning a BufferedReader that may be used to read text from the file in an efficient manner.
static BufferedWriter	newBufferedWriter(Path path, Charset cs,OpenOption... options) Opens or creates a file for writing, returning a BufferedWriter that may be used to write text to the file in an efficient manner.
static BufferedWriter	newBufferedWriter(Path path, OpenOption... options) Opens or creates a file for writing, returning a BufferedWriter to write text to the file in an efficient manner.
static SeekableByteChannel	newByteChannel(Path path, OpenOption... options) Opens or creates a file, returning a seekable byte channel to access the file.
static SeekableByteChannel	newByteChannel(Path path, Set<? extends OpenOption> options,FileAttribute<?>... attrs) Opens or creates a file, returning a seekable byte channel to access the file.

参数：--OpenOption

                      --StandardOpenOption（对文件读写访问的控制）

 

APPEND If the file is opened for WRITE access then bytes will be written to the end of the file rather than the beginning.

CREATE Create a new file if it does not exist.

CREATE_NEW Create a new file, failing if the file already exists.

DELETE_ON_CLOSE Delete on close.

DSYNC Requires that every update to the file's content be written synchronously to the underlying storage device.

READ Open for read access.

SPARSE Sparse file.

SYNC Requires that every update to the file's content or metadata be written synchronously to the underlying storage device.

TRUNCATE_EXISTING If the file already exists and it is opened for WRITE access, then its length is truncated to 0.

WRITE Open for write access.