Java模式/匹配器

问题描述

这是示例文本: \ 1f \ 1e \ 1d \ 020028 .我无法修改输入文本，我正在从文件中读取一长串文本.

This is a sample text: \1f\1e\1d\020028. I cannot modify the input text, I am reading long string of texts from a file.

我要提取以下内容: \ 1f ， \ 1e ， \ 1d ， \ 02

I want to extract the following: \1f, \1e, \1d, \02

为此，我编写了以下正则表达式模式:"\\ [a-fA-F0-9]"

For this, I have written the following regular expression pattern: "\\[a-fA-F0-9]"

我正在使用 Pattern 和 Matcher 类，但是我的匹配器无法使用上述正则表达式找到模式.我已经在一些在线正则表达式网站上用文本测试了此正则表达式，并且令人惊讶的是，它可以在其中工作.

I am using Pattern and Matcher classes, but my matcher is not able find the pattern using the mentioned regular expression. I have tested this regex with the text on some online regex websites and surprisingly it works there.

我要去哪里错了?

原始代码:

public static void main(String[] args) {
    String inputText = "\1f\1e\1d\02002868BF03030000000000000000S023\1f\1e\1d\03\0d";
    inputText        = inputText.replace("\\", "\\\\");

    String regex     = "\\\\[a-fA-F0-9]{2}";

    Pattern p = Pattern.compile(regex);
    Matcher m = p.matcher(inputText);

    while (m.find()) {
        System.out.println(m.group());
    }
}

输出:什么都没打印

推荐答案

您需要正确阅读文件，并将'\'字符替换为'\\'.假设您的项目中有一个名为test_file的文件，其内容如下:

You need to read the file properly and replace '\' characters with '\\'. Assume that there is file called test_file in your project with this content:

\1f\1e\1d\02002868BF03030000000000000000S023\1f\1e\1d\03\0d

以下是读取文件和提取值的代码:

Here is the code to read the file and extract values:

public static void main(String[] args) throws IOException, URISyntaxException {
    Test t = new Test();
    t.test();
}

public void test() throws IOException {
    BufferedReader br =
        new BufferedReader(
            new InputStreamReader(
                getClass().getResourceAsStream("/test_file.txt"), "UTF-8"));
    String inputText;

    while ((inputText = br.readLine()) != null) {
        inputText = inputText.replace("\\", "\\\\");

        Pattern pattern = Pattern.compile("\\\\[a-fA-F0-9]{2}");
        Matcher match = pattern.matcher(inputText);

        while (match.find()) {
            System.out.println(match.group());
        }
    }
}

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