java - 带有 Servlet 3.0 的嵌入式 Tomcat - 扫描时如何跳过某些 jar？

Question

下面是一个扫描 Servlet 3.0 初始值设定项的嵌入式 Tomcat 服务器的简单方法:

public static void main(String[] args) throws ServletException, LifecycleException {
    Tomcat tomcat = new Tomcat();
    tomcat.setPort(8080);

    StandardContext ctx = (StandardContext) tomcat.addWebapp("/", new File("web").getAbsolutePath());

    //declare an alternate location for your "WEB-INF/classes" dir:     
    File additionWebInfClasses = new File("target/classes");
    VirtualDirContext resources = new VirtualDirContext();
    resources.setExtraResourcePaths("/WEB-INF/classes=" + additionWebInfClasses);
    ctx.setResources(resources);

    tomcat.start();
    System.out.println("Started");
    tomcat.getServer().await();
}

我知道 catalina.properties 中的属性 tomcat.util.scan.DefaultJarScanner.jarsToSkip 允许您限制扫描哪些 jar 以加快部署时间。我如何将同样的想法合并到此处的嵌入式 Tomcat 代码中？

奖励:有没有一种方法可以指定包含而不是跳过哪些jar？

Answer 1

虽然我没有加载单个 catalina.properties 属性的特定方法，但我发现只需在 Tomcat 容器上下文中重载 JarScanner 本身就足够方便了，如下所示:

答案在 Groovy 中(抱歉，我偷懒了)

public static void main(String[] args) throws ServletException, LifecycleException {
    Tomcat tomcat = new TomcatWithFastJarScanner()
    tomcat.setPort(8080)

    StandardContext ctx = (StandardContext) tomcat.addWebapp("/", new File("web").getAbsolutePath())

    //declare an alternate location for your "WEB-INF/classes" dir:     
    VirtualDirContext resources = new VirtualDirContext()
    resources.setExtraResourcePaths("/WEB-INF/classes=" + new File("target/classes"))
    ctx.setResources(resources)

    tomcat.start()
    println "Started server on port 8080"
    tomcat.getServer().await()
}

private static class TomcatWithFastJarScanner extends Tomcat {
    @Override
    public void start() throws LifecycleException {
        getServer().findServices().each { service ->
            service.getContainer().findChildren().each { container ->
                container.findChildren().each { c ->
                    ((Context) c).setJarScanner(new FastJarScanner())
                }
            }
        }
        super.start()
    }
}


private static class FastJarScanner extends StandardJarScanner {
    def jarsToInclude = [ 'spring-web.*' ]

    @Override
    public void scan(ServletContext context, ClassLoader classloader,
            JarScannerCallback callback, Set<String> jarsToSkip) {
        jarsToSkip = new HashSet<String>();

        ((URLClassLoader) classloader.getParent()).getURLs().each {
            def jar = it.path.find(/[^\/]+\.jar$/)
            if(!jar) return
            for(String inclusionPattern : jarsToInclude) {
                if(jar.find(inclusionPattern))  
                    println "including jar: " + jar
                else jarsToSkip.add(jar)
            }
        }

        super.scan(context, classloader, callback, jarsToSkip);
    }
}

基本思想是我们查看类加载器可以看到的所有 jar，并排除所有我们不想包含的 jar。

Tomcat 嵌入式启动速度非常快!