import java.nio.file.Path;
import java.nio.file.Paths;

public class PathExample {

    public static void main(String[] args) {
        // 創(chuàng)建一個(gè)絕對(duì)路徑
        Path absolutePath = Paths.get("C:\\Users\\phoenix\\file.txt");     // 這里傳入 "example\\file.txt" 創(chuàng)建的相對(duì)路徑
        System.out.println("Absolute path: " + absolutePath);
        // 獲取父路徑
        System.out.println("Parent path: " + absolutePath.getParent());
        // 獲取文件名
        System.out.println("File name: " + absolutePath.getFileName());
        // 獲取根路徑
        System.out.println("Root path: " + absolutePath.getRoot());
        // 合并路徑
        Path resolvePath = Paths.get("C:\\Users\\phoenix").resolve("file.txt");
        System.out.println("Merged path:" + resolvePath);
    }
}

Absolute path: C:\Users\phoenix\file.txt
Parent path: C:\Users\phoenix
File name: file.txt
Root path: C:\
Merged path:C:\Users\phoenix\file.txt

import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.util.Arrays;
import java.util.List;

public class PathExample {

    public static void main(String[] args) throws IOException {
        Path path = Paths.get("example.txt");
        // 1：檢查文件是否存在
        boolean exists = Files.exists(path);
        System.out.println("File exists: " + exists);
        if (!exists) {
            // 2：不存在則創(chuàng)建文件
            Files.createFile(path);
        }
        // 3：復(fù)制一個(gè)文件
        Path target = Paths.get("example2.txt");
        Files.copy(path, target, StandardCopyOption.REPLACE_EXISTING);
        // 4：創(chuàng)建目錄
        Path newDirectory = Paths.get("example");
        Files.createDirectories(newDirectory);
        // 4：移動(dòng)文件：將 example2.txt 移動(dòng)到 example 目錄下
        Files.move(target, newDirectory.resolve("example2.txt"), StandardCopyOption.REPLACE_EXISTING);
        // 5：刪除文件和目錄
        Files.delete(newDirectory.resolve("example2.txt"));
        Files.delete(newDirectory);				// 只能刪除空目錄
        // 6：將字節(jié)數(shù)組寫入文件
        Files.write(path, "Hello World".getBytes());
        // 7：將文本行序列寫入文件
        List<String> lines = Arrays.asList("Line 1", "Line 2", "Line 3");
        Files.write(path, lines, StandardCharsets.UTF_8, StandardOpenOption.CREATE);
        // 8：讀取文件，并且打印所有行
        Files.readAllLines(path, StandardCharsets.UTF_8).forEach(System.out::println);
    }
}

File exists: true
Line 1
Line 2
Line 3

public class FileSystemsExample {

    public static void main(String[] args) {
        // 獲取默認(rèn)文件系統(tǒng)
        FileSystem fileSystem = FileSystems.getDefault();
        // 獲取文件系統(tǒng)的路徑分隔符
        String pathSeparator = fileSystem.getSeparator();
        System.out.println("Path separator: " + pathSeparator);
        // 獲取文件系統(tǒng)的根目錄
        for (Path root : fileSystem.getRootDirectories()) {
            System.out.println("Root directory: " + root);
        }
        // 使用文件系統(tǒng)創(chuàng)建一個(gè) path 路徑對(duì)象
        Path path = fileSystem.getPath("path", "to", "file.txt");
        System.out.println(path);
        // 是否只讀
        System.out.println("is read only ?: " + fileSystem.isReadOnly());
        // 文件系統(tǒng)的提供者
        System.out.println("provider: " + fileSystem.provider());
    }
}

Path separator: \
Root directory: C:\
path\to\file.txt
is read only ?: false
provider: sun.nio.fs.WindowsFileSystemProvider@5b480cf9

import java.io.IOException;
import java.nio.file.*;

public class WatchServiceExample {

    public static void main(String[] args) throws IOException, InterruptedException {
        // 創(chuàng)建 WatchService
        WatchService watchService = FileSystems.getDefault().newWatchService();

        // 注冊(cè)監(jiān)聽指定的目錄
        Path dir = Paths.get("C:\\Users\\phoenix");
        dir.register(watchService, StandardWatchEventKinds.ENTRY_CREATE, StandardWatchEventKinds.ENTRY_MODIFY, StandardWatchEventKinds.ENTRY_DELETE);

        while (true) {
            // 獲取并處理事件
            WatchKey key = watchService.take();
            for (WatchEvent<?> event : key.pollEvents()) {
                System.out.println("Event: " + event.kind() + " - " + event.context());
            }

            // 重置 key，繼續(xù)監(jiān)聽
            if (!key.reset()) {
                break;
            }
        }
        watchService.close();
    }
}

Event: ENTRY_CREATE - 新建 文本文檔.txt
Event: ENTRY_DELETE - 新建 文本文檔.txt
Event: ENTRY_CREATE - helloWorld.txt
Event: ENTRY_MODIFY - helloWorld.txt
Event: ENTRY_MODIFY - helloWorld.txt
Event: ENTRY_MODIFY - helloWorld.txt
Event: ENTRY_DELETE - helloWorld.txt

import java.io.IOException;
import java.nio.file.*;
import java.util.stream.Stream;

public class PathMatcherExample {

    public static void main(String[] args) throws IOException {
        // 創(chuàng)建 PathMatcher，使用 glob 語(yǔ)法：匹配所有以 .tmp 結(jié)尾的文件（臨時(shí)文件）
        FileSystem fileSystem = FileSystems.getDefault();
        PathMatcher matcher = fileSystem.getPathMatcher("glob:*.tmp");
        // 在指定目錄，找到匹配的文件，然后進(jìn)行刪除
        try (Stream<Path> walk = Files.walk(Paths.get("path/to/directory"))) {
            walk.filter(path -> matcher.matches(path.getFileName())).forEach(path -> {
                System.out.println(path.getFileName());
                try {
                    Files.delete(path);
                } catch (IOException e) {
                    throw new RuntimeException(e);
                }
            });
        }
    }
}

Java is a high-level programming language.
Python is an interpreted, high-level programming language.
JavaScript is a scripting language for Web development.
C++ is a general-purpose programming language.
Rust is a systems programming language.

public class LinesExample {
    public static void main(String[] args) throws IOException {
        // 讀取全部文件
        List<String> lines = Files.readAllLines(Paths.get("path/to/file.txt"), StandardCharsets.UTF_8);
        // 對(duì)文件內(nèi)容進(jìn)行處理
        Map<String, Long> wordFrequency = lines.stream()
                .flatMap(line -> Arrays.stream(line.split("\\s+")))
                .map(String::toLowerCase)
                .collect(Collectors.groupingBy(word -> word, Collectors.counting()));
        System.out.println("Word Frequency:");
        wordFrequency.forEach((word, count) -> System.out.printf("%s: %d%n", word, count));
    }
}

public class LinesExample {

    public static void main(String[] args) throws IOException {
        Path filePath = Paths.get("path/to/file.txt");

        // 逐行讀取，并且在內(nèi)容進(jìn)行處理
        Stream<String> lines = Files.lines(filePath);
        Map<String, Long> wordFrequency = lines
                .skip(3)            // 跳過前 3 行
                .flatMap(line -> Arrays.stream(line.split("\\s+")))
                .map(String::toLowerCase)
                .collect(Collectors.groupingBy(word -> word, Collectors.counting()));

        System.out.println("Word Frequency:");
        wordFrequency.forEach((word, count) -> System.out.printf("%s: %d%n", word, count));
        lines.close();
    }
}

Word Frequency:
rust: 1
a: 2
c++: 1
systems: 1
language.: 2
is: 2
programming: 2
general-purpose: 1