import sun.security.tools.PathList; //导入依赖的package包/类
private ContentSigner loadSigningMechanism(String signerClassName,
    String signerClassPath) throws Exception {

    // construct class loader
    String cpString = null;   // make sure env.class.path defaults to dot

    // do prepends to get correct ordering
    cpString = PathList.appendPath(System.getProperty("env.class.path"), cpString);
    cpString = PathList.appendPath(System.getProperty("java.class.path"), cpString);
    cpString = PathList.appendPath(signerClassPath, cpString);
    URL[] urls = PathList.pathToURLs(cpString);
    ClassLoader appClassLoader = new URLClassLoader(urls);

    // attempt to find signer
    Class<?> signerClass = appClassLoader.loadClass(signerClassName);

    // Check that it implements ContentSigner
    Object signer = signerClass.newInstance();
    if (!(signer instanceof ContentSigner)) {
        MessageFormat form = new MessageFormat(
            rb.getString("signerClass.is.not.a.signing.mechanism"));
        Object[] source = {signerClass.getName()};
        throw new IllegalArgumentException(form.format(source));
    }
    return (ContentSigner)signer;
}
 

import sun.security.tools.PathList; //导入依赖的package包/类
@SuppressWarnings("deprecation")
private ContentSigner loadSigningMechanism(String signerClassName,
                                           String signerClassPath) {

    // construct class loader
    String cpString;   // make sure env.class.path defaults to dot

    // do prepends to get correct ordering
    cpString = PathList.appendPath(
            System.getProperty("env.class.path"), null);
    cpString = PathList.appendPath(
            System.getProperty("java.class.path"), cpString);
    cpString = PathList.appendPath(signerClassPath, cpString);
    URL[] urls = PathList.pathToURLs(cpString);
    ClassLoader appClassLoader = new URLClassLoader(urls);

    try {
        // attempt to find signer
        Class<?> signerClass = appClassLoader.loadClass(signerClassName);
        Object signer = signerClass.newInstance();
        return (ContentSigner) signer;
    } catch (ClassNotFoundException|InstantiationException|
            IllegalAccessException|ClassCastException e) {
        throw new IllegalArgumentException(
                "Invalid altSigner or altSignerPath", e);
    }
}