Question

任何人都可以详细解释这段代码及其组件的作用吗？我对使用进程或Android本机代码不是很熟悉。如果有人能解释这段代码是如何工作的话会很棒：

private static MatchResult matchSystemFile(final String pSystemFile, final String pPattern, final int pHorizon) throws SystemUtilsException {
    InputStream in = null;
    try {
        final Process process = new ProcessBuilder(new String[] { "/system/bin/cat", pSystemFile }).start();

        in = process.getInputStream();
        final Scanner scanner = new Scanner(in);

        final boolean matchFound = scanner.findWithinHorizon(pPattern, pHorizon) != null;
        if(matchFound) {
            return scanner.match();
        } else {
            throw new SystemUtilsException();
        }
    } catch (final IOException e) {
        throw new SystemUtilsException(e);
    } finally {
        StreamUtils.close(in);
    }
}

private static int readSystemFileAsInt(final String pSystemFile) throws SystemUtilsException {
    InputStream in = null;
    try {
        final Process process = new ProcessBuilder(new String[] { "/system/bin/cat", pSystemFile }).start();

        in = process.getInputStream();
        final String content = StreamUtils.readFully(in);
        return Integer.parseInt(content);
    } catch (final IOException e) {
        throw new SystemUtilsException(e);
    } catch (final NumberFormatException e) {
        throw new SystemUtilsException(e);
    } finally {
        StreamUtils.close(in);
    }
}

我需要理解这一部分，进程如何处理两个字符串，我无法理解这个代码如何在两个文件上工作（对我来说它看起来像/ system / bin / cat和pSystemFile字符串是文件的路径）并提取所需信息。

 final Process process = new ProcessBuilder(new String[] { "/system/bin/cat", pSystemFile }).start();

    in = process.getInputStream();
    final Scanner scanner = new Scanner(in);

    final boolean matchFound = scanner.findWithinHorizon(pPattern, pHorizon) != null;
    if(matchFound) {
        return scanner.match();
    }

此代码取自AndEngines Utils。

的问候， Aqif Hamid

Answer 1

两种方法都接受文件名作为参数，并运行cat实用程序将文件路径传递给它。然后两个方法都读取外部进程的输出：首先使用Scanner，第二个StreamUtils一次读取所有内容，然后将内容解析为整数。

理解一些Java代码 - 我需要一些解释

1 个答案: