用特殊格式从JAR中提取类名

Question

如何从Jar文件中提取所有可用的类，并在经过一些简单处理后将输出转储到txt文件。

例如，如果我运行jar tf commons-math3-3.1.6.jar，输出的一个子集将是：

org/apache/commons/math3/analysis/differentiation/UnivariateVectorFunctionDifferentiator.class
org/apache/commons/math3/analysis/differentiation/FiniteDifferencesDifferentiator$2.class
org/apache/commons/math3/analysis/differentiation/SparseGradient$1.class
org/apache/commons/math3/analysis/integration/IterativeLegendreGaussIntegrator$1.class
org/apache/commons/math3/analysis/integration/gauss/LegendreHighPrecisionRuleFactory.class
org/apache/commons/math3/analysis/integration/gauss/BaseRuleFactory.class
org/apache/commons/math3/analysis/integration/gauss/HermiteRuleFactory.class
org/apache/commons/math3/analysis/integration/gauss/LegendreRuleFactory.class
org/apache/commons/math3/analysis/integration/gauss/GaussIntegratorFactory.class

我想把所有的/转换成.

以及$ to .

最后，我还想删除出现在每个字符串末尾的.class。

例如：

org/apache/commons/math3/analysis/differentiation/FiniteDifferencesDifferentiator$2.class

会变成

org.apache.commons.math3.analysis.differentiation.FiniteDifferencesDifferentiator.2

Answer 1

String path = "org/apache/commons/math3/analysis/integration/gauss/BaseRuleFactory.class";
path = path.replaceAll("/", ".")
           .replaceAll("\\$(\\d+)\\.class", "\\.$1");

Answer 2

在我看来，在程序中执行shell命令不是很好，所以您可以做的是以编程的方式检查文件。

以这个例子为例，我们将在classNames中填充/path/to/jar/file.jar.中包含在jar文件中的所有Java类的列表

List<String> classNames = new ArrayList<String>();
ZipInputStream zip = new ZipInputStream(new FileInputStream("/path/to/jar/file.jar"));
for (ZipEntry entry = zip.getNextEntry(); entry != null; entry = zip.getNextEntry()) {
    if (!entry.isDirectory() && entry.getName().endsWith(".class")) {
        // This ZipEntry represents a class. Now, what class does it represent?
        String className = entry.getName().replace('/', '.').replace('$',''); // including ".class"
        classNames.add(className.substring(0, className.length() - ".class".length()));
    }
}

信贷：Here