java中直接到桌面的绝对路径，即使在不同的计算机中也是如此

Question

即使在不同的计算机中，我如何能够自动将BufferReader Path定向到桌面。。'''BufferedReader in=新的BufferedReader(新的FileReader("C:\Users\….\".txt"((；'''

Answer 1

您可以使用

  public static void main(String[] args) throws IOException {
    String path = System.getProperty("user.home") + "/Desktop/test.txt";
    BufferedReader in = new BufferedReader(new FileReader(path));
    String line;
    while ((line = in.readLine()) != null) {
      System.out.println("line = " + line);
    }
    in.close();
  }

获取桌面路径并从中读取文本文件

Answer 2

以下是获取桌面目录的方法：

• 在Windows中，我查看HKCUSoftwareMicrosoftWindowsCurrentVersionExplorerShell Folders中的DESKTOP注册表项
• 在Linux中，我扫描纯文本文件$XFG_CONFIG_HOME/user-dirs.dirs，查找类似外壳的XDG_DESKTOP_DIR变量定义
• 在其他系统上，或者如果以上操作失败，请回退到用户主目录中的Desktop目录

我的实现如下：

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.Files;
import java.util.regex.Pattern;
public class DesktopDirectoryLocator {
    public static Path getDesktopDirectory()
    throws IOException,
           InterruptedException {
        String os = System.getProperty("os.name");
        if (os.contains("Windows")) {
            String dir = null;
            ProcessBuilder builder = new ProcessBuilder("reg.exe", "query",
                "HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer"
                + "\Shell Folders", "/v", "DESKTOP");
            builder.redirectError(ProcessBuilder.Redirect.INHERIT);
            Process regQuery = builder.start();
            try (BufferedReader outputReader = new BufferedReader(
                new InputStreamReader(regQuery.getInputStream()))) {
                String line;
                while ((line = outputReader.readLine()) != null) {
                    if (dir == null) {
                        String replaced =
                            line.replaceFirst("^\s*DESKTOP\s+REG_SZ\s+", "");
                        if (!replaced.equals(line)) {
                            dir = replaced.trim();
                        }
                    }
                }
            }
            int exitCode = regQuery.waitFor();
            if (exitCode != 0) {
                throw new IOException(
                    "Command " + builder.command() + " returned " + exitCode);
            }
            if (dir != null) {
                return Paths.get(dir);
            }
        } else if (os.contains("Linux")) {
            // Reference:
            // https://www.freedesktop.org/wiki/Software/xdg-user-dirs/
            // https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html
            Path configDir;
            String configHome = System.getenv("XDG_CONFIG_HOME");
            if (configHome != null) {
                configDir = Paths.get(configHome);
            } else {
                configDir = Paths.get(
                    System.getProperty("user.home"), ".config");
            }
            Path userDirsFile = configDir.resolve("user-dirs.dirs");
            if (Files.isRegularFile(userDirsFile)) {
                try (BufferedReader userDirs =
                    Files.newBufferedReader(userDirsFile)) {
                    String line;
                    while ((line = userDirs.readLine()) != null) {
                        if (line.trim().startsWith("XDG_DESKTOP_DIR=")) {
                            String value =
                                line.substring(line.indexOf('=') + 1);
                            if (value.startsWith(""") &&
                                value.endsWith(""")) {
                                value = value.substring(1, value.length() - 1);
                            }
                            Pattern varPattern = Pattern.compile(
                                "\$(\{[^}]+\}|[a-zA-Z0-9_]+)");
                            value = varPattern.matcher(value).replaceAll(r -> {
                                String varName = r.group(1);
                                if (varName.startsWith("{")) {
                                    varName = varName.substring(1,
                                        varName.length() - 1);
                                }
                                String varValue = System.getenv(varName);
                                return (varValue != null ?
                                    varValue : r.group());
                            });
                            return Paths.get(value);
                        }
                    }
                }
            }
        }
        return Paths.get(System.getProperty("user.home"), "Desktop");
    }
    public static void main(String[] args)
    throws IOException,
           InterruptedException {
        System.out.println(getDesktopDirectory());
    }
}

要读取该目录中的文件，您可以使用：

Path desktopDir = getDesktopDirectory();
Path file = desktopDir.resolve("example.txt");
try (BufferedReader reader = Files.newBufferedReader(file,
    Charset.defaultCharset())) {
    // ... 
}