检测Java中硬链接文件路径的实用指南

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;
import java.util.UUID;

public class HardLinkDetection {

    public static void main(String[] args) {
        // 创建一个临时目录用于测试
        Path tempDir = Paths.get("temp_test_dir_" + UUID.randomUUID().toString());
        try {
            Files.createDirectory(tempDir);
            System.out.println("Created temporary directory: " + tempDir.toAbsolutePath());

            Path originalFile = tempDir.resolve("original.txt");
            Path hardLinkFile = tempDir.resolve("hardlink.txt");
            Path differentFile = tempDir.resolve("different.txt");
            Path symLinkFile = tempDir.resolve("symlink.txt");

            // 1. 创建原始文件
            Files.writeString(originalFile, "Hello, Hard Links!", StandardOpenOption.CREATE_NEW);
            System.out.println("Created original file: " + originalFile.toAbsolutePath());

            // 2. 创建硬链接到原始文件
            // 注意：Files.createLink() 在某些文件系统上可能需要管理员权限或特定配置
            try {
                Files.createLink(hardLinkFile, originalFile);
                System.out.println("Created hard link: " + hardLinkFile.toAbsolutePath());
            } catch (UnsupportedOperationException e) {
                System.err.println("Hard links not supported on this file system or OS: " + e.getMessage());
                System.out.println("Skipping hard link test.");
                hardLinkFile = null; // Mark as not created for later checks
            } catch (IOException e) {
                System.err.println("Error creating hard link: " + e.getMessage());
                System.out.println("Skipping hard link test.");
                hardLinkFile = null;
            }


            // 3. 创建一个不同的文件
            Files.writeString(differentFile, "This is a different file.", StandardOpenOption.CREATE_NEW);
            System.out.println("Created different file: " + differentFile.toAbsolutePath());

            // 4. 创建一个符号链接到原始文件 (如果支持)
            try {
                Files.createSymbolicLink(symLinkFile, originalFile);
                System.out.println("Created symbolic link: " + symLinkFile.toAbsolutePath());
            } catch (UnsupportedOperationException e) {
                System.err.println("Symbolic links not supported on this file system or OS: " + e.getMessage());
                System.out.println("Skipping symbolic link test.");
                symLinkFile = null;
            } catch (IOException e) {
                System.err.println("Error creating symbolic link: " + e.getMessage());
                System.out.println("Skipping symbolic link test.");
                symLinkFile = null;
            }


            System.out.println("\n--- Testing Files.isSameFile() ---");

            // 场景1: 原始文件与自身
            System.out.println("Is " + originalFile.getFileName() + " same as " + originalFile.getFileName() + "? " +
                               Files.isSameFile(originalFile, originalFile)); // 预期: true

            // 场景2: 原始文件与硬链接文件
            if (hardLinkFile != null) {
                System.out.println("Is " + originalFile.getFileName() + " same as " + hardLinkFile.getFileName() + "? " +
                                   Files.isSameFile(originalFile, hardLinkFile)); // 预期: true
            }

            // 场景3: 原始文件与不同文件
            System.out.println("Is " + originalFile.getFileName() + " same as " + differentFile.getFileName() + "? " +
                               Files.isSameFile(originalFile, differentFile)); // 预期: false

            // 场景4: 原始文件与符号链接文件
            if (symLinkFile != null) {
                // Files.isSameFile() 会解析符号链接
                System.out.println("Is " + originalFile.getFileName() + " same as " + symLinkFile.getFileName() + "? " +
                                   Files.isSameFile(originalFile, symLinkFile)); // 预期: true
            }

            // 场景5: 硬链接文件与不同文件
            if (hardLinkFile != null) {
                System.out.println("Is " + hardLinkFile.getFileName() + " same as " + differentFile.getFileName() + "? " +
                                   Files.isSameFile(hardLinkFile, differentFile)); // 预期: false
            }

        } catch (IOException e) {
            System.err.println("An I/O error occurred: " + e.getMessage());
            e.printStackTrace();
        } finally {
            // 清理临时文件和目录
            try {
                if (Files.exists(tempDir)) {
                    Files.walk(tempDir)
                            .sorted(java.util.Comparator.reverseOrder())
                            .map(Path::toFile)
                            .forEach(java.io.File::delete);
                    System.out.println("\nCleaned up temporary directory: " + tempDir.toAbsolutePath());
                }
            } catch (IOException e) {
                System.err.println("Error during cleanup: " + e.getMessage());
            }
        }
    }
}