Paths 路径工具类
@Test
public void test1() {
Path path = Paths.get("e:/", "nio/hello.txt");
System.out.println(path.endsWith("hello.txt"));
System.out.println(path.startsWith("e:/"));
System.out.println(path.isAbsolute());
System.out.println(path.getFileName());
for (int i = 0; i < path.getNameCount(); i++) {
System.out.println(path.getName(i));
}
}
/**
* <pre>
* Paths 提供的 get() 方法用来获取 Path 对象:
* Path get(String first, String … more) : 用于将多个字符串串连成路径。
*
* Path 常用方法:
* boolean endsWith(String path) : 判断是否以 path 路径结束
* boolean startsWith(String path) : 判断是否以 path 路径开始
* boolean isAbsolute() : 判断是否是绝对路径
* Path getFileName() : 返回与调用 Path 对象关联的文件名
* Path getName(int idx) : 返回的指定索引位置 idx 的路径名称
* int getNameCount() : 返回Path 根目录后面元素的数量
* Path getParent() :返回Path对象包含整个路径,不包含 Path 对象指定的文件路径
* Path getRoot() :返回调用 Path 对象的根路径
* Path resolve(Path p) :将相对路径解析为绝对路径
* Path toAbsolutePath() : 作为绝对路径返回调用 Path 对象
* String toString() : 返回调用 Path 对象的字符串表示形式
* </pre>
*/
@Test
public void test2() {
Path path = Paths.get("e:/nio/hello.txt");
System.out.println(path.getParent());
System.out.println(path.getRoot());
System.out.println(path.toString());
System.out.println("=====================");
// Path newPath = path.resolve("e:/hello.txt");
// System.out.println(newPath);
Path path2 = Paths.get("1.jpg");
Path newPath = path2.toAbsolutePath();
System.out.println(newPath);
}
Files 工具类
@Test
public void test3() throws IOException {
Path path1 = Paths.get("e:/nio/hello.txt");
Path path2 = Paths.get("e:/nio/hello2.txt");
Files.copy(path1, path2, StandardCopyOption.REPLACE_EXISTING);
}
@Test
public void test4() throws IOException {
Path dir = Paths.get("e:/nio/nio2");
// Files.createDirectory(dir);
Path file = Paths.get("e:/nio/nio2/hello3.txt");
// Files.createFile(file);
Files.deleteIfExists(file);
}
/**
* <pre>
* Files常用方法:
* Path copy(Path src, Path dest, CopyOption … how) : 文件的复制
* Path createDirectory(Path path, FileAttribute<?> … attr) : 创建一个目录
* Path createFile(Path path, FileAttribute<?> … arr) : 创建一个文件
* void delete(Path path) : 删除一个文件
* Path move(Path src,Path dest, CopyOption…how) : 将 src 移动到 dest 位置
* long size(Path path) : 返回 path 指定文件的大小
* </pre>
*/
@Test
public void test5() throws IOException {
Path path1 = Paths.get("e:/nio/hello2.txt");
Path path2 = Paths.get("e:/nio/hello7.txt");
System.out.println(Files.size(path2));
// Files.move(path1, path2, StandardCopyOption.ATOMIC_MOVE);
}
/**
* <pre>
* Files常用方法:
* boolean exists(Path path, LinkOption … opts) : 判断文件是否存在
* boolean isDirectory(Path path, LinkOption … opts) : 判断是否是目录
* boolean isExecutable(Path path) : 判断是否是可执行文件
* boolean isHidden(Path path) : 判断是否是隐藏文件
* boolean isReadable(Path path) : 判断文件是否可读
* boolean isWritable(Path path) : 判断文件是否可写
* boolean notExists(Path path, LinkOption … opts) : 判断文件是否不存在
* public static <A extends BasicFileAttributes> A readAttributes(Path path,Class<A> type,LinkOption... options) : 获取与 path 指定的文件相关联的属性。
* </pre>
*/
@Test
public void test6() throws IOException {
Path path = Paths.get("e:/nio/hello7.txt");
// System.out.println(Files.exists(path, LinkOption.NOFOLLOW_LINKS));
BasicFileAttributes readAttributes = Files.readAttributes(path, BasicFileAttributes.class,
LinkOption.NOFOLLOW_LINKS);
System.out.println(readAttributes.creationTime());
System.out.println(readAttributes.lastModifiedTime());
DosFileAttributeView fileAttributeView = Files.getFileAttributeView(path, DosFileAttributeView.class,
LinkOption.NOFOLLOW_LINKS);
fileAttributeView.setHidden(false);
}
/**
* <pre>
* Files 常用方法:用于操作内容
*
* SeekableByteChannel newByteChannel(Path path, OpenOption…how) : 获取与指定文件的连接,how 指定打开方式。
* DirectoryStream newDirectoryStream(Path path) : 打开 path 指定的目录
*
* InputStream newInputStream(Path path, OpenOption…how):获取 InputStream 对象
* OutputStream newOutputStream(Path path, OpenOption…how) : 获取 OutputStream 对象
* </pre>
*/
@Test
public void test7() throws IOException {
SeekableByteChannel newByteChannel = Files.newByteChannel(Paths.get("1.jpg"), StandardOpenOption.READ);
DirectoryStream<Path> newDirectoryStream = Files.newDirectoryStream(Paths.get("e:/"));
for (Path path : newDirectoryStream) {
System.out.println(path);
}
}
自动资源管理:自动关闭实现 AutoCloseable 接口的资源
@Test
public void test8() {
try (FileChannel inChannel = FileChannel.open(Paths.get("1.jpg"), StandardOpenOption.READ);
FileChannel outChannel = FileChannel.open(Paths.get("2.jpg"), StandardOpenOption.WRITE,
StandardOpenOption.CREATE)) {
ByteBuffer buf = ByteBuffer.allocate(1024);
inChannel.read(buf);
} catch (IOException e) {
}
}