从类路径目录中获取资源列表 [英] Get a list of resources from classpath directory

问题描述

我正在寻找一种方法来从给定的类路径目录中获取所有资源名称的列表，类似于方法 List;getResourceNames (String directoryName).

I am looking for a way to get a list of all resource names from a given classpath directory, something like a method List<String> getResourceNames (String directoryName).

例如，给定一个包含文件 a.html、b.html、c 的类路径目录 x/y/z.html 和一个子目录 d，getResourceNames("x/y/z") 应该返回一个 List 包含以下字符串:['a.html', 'b.html', 'c.html', 'd'].

For example, given a classpath directory x/y/z containing files a.html, b.html, c.html and a subdirectory d, getResourceNames("x/y/z") should return a List<String> containing the following strings:['a.html', 'b.html', 'c.html', 'd'].

它应该适用于文件系统和 jar 中的资源.

It should work both for resources in filesystem and jars.

我知道我可以用 Files、JarFiles 和 URLs 编写一个快速片段，但我不想重新发明轮.我的问题是，鉴于现有的公共可用库，实现 getResourceNames 的最快方法是什么?Spring 和 Apache Commons 堆栈都是可行的.

I know that I can write a quick snippet with Files, JarFiles and URLs, but I do not want to reinvent the wheel. My question is, given existing publicly available libraries, what is the quickest way to implement getResourceNames? Spring and Apache Commons stacks are both feasible.

推荐答案

Custom Scanner

实现您自己的扫描仪.例如:

Custom Scanner

Implement your own scanner. For example:

(评论中提到了此解决方案的局限性)

private List<String> getResourceFiles(String path) throws IOException {
    List<String> filenames = new ArrayList<>();

    try (
            InputStream in = getResourceAsStream(path);
            BufferedReader br = new BufferedReader(new InputStreamReader(in))) {
        String resource;

        while ((resource = br.readLine()) != null) {
            filenames.add(resource);
        }
    }

    return filenames;
}

private InputStream getResourceAsStream(String resource) {
    final InputStream in
            = getContextClassLoader().getResourceAsStream(resource);

    return in == null ? getClass().getResourceAsStream(resource) : in;
}

private ClassLoader getContextClassLoader() {
    return Thread.currentThread().getContextClassLoader();
}

Spring 框架

使用 PathMatchingResourcePatternResolver 来自 Spring 框架.

Spring Framework

Use PathMatchingResourcePatternResolver from Spring Framework.

对于巨大的 CLASSPATH 值，其他技术在运行时可能会很慢.更快的解决方案是使用 ronmamo 的 Reflections API，它在编译时预编译搜索.

The other techniques might be slow at runtime for huge CLASSPATH values. A faster solution is to use ronmamo's Reflections API, which precompiles the search at compile time.

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