Java 类org.apache.catalina.loader.WebappClassLoaderBase 实例源码

/**
 * Attempt to identify the contexts that have a class loader memory leak.
 * This is usually triggered on context reload. Note: This method attempts
 * to force a full garbage collection. This should be used with extreme
 * caution on a production system.
 */
public String[] findReloadedContextMemoryLeaks() {

    System.gc();

    List<String> result = new ArrayList<String>();

    for (Map.Entry<ClassLoader, String> entry :
            childClassLoaders.entrySet()) {
        ClassLoader cl = entry.getKey();
        if (cl instanceof WebappClassLoaderBase) {
            if (!((WebappClassLoaderBase) cl).isStarted()) {
                result.add(entry.getValue());
            }
        }
    }

    return result.toArray(new String[result.size()]);
}

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {
    resp.setContentType("text/plain");
    PrintWriter out = resp.getWriter();

    ClassLoader system = ClassLoader.getSystemClassLoader();

    ClassLoader cl = Thread.currentThread().getContextClassLoader();
    while (cl != null) {
        if (system == cl) {
            out.print("SYSTEM,");
        } else if (custom == cl) {
            out.print("CUSTOM,");
        } else if (cl instanceof WebappClassLoaderBase) {
            out.print("WEBAPP,");
        } else {
            out.print("OTHER,");
        }
        cl = cl.getParent();
    }
}

/**
 * Attempt to identify the contexts that have a class loader memory leak.
 * This is usually triggered on context reload. Note: This method attempts
 * to force a full garbage collection. This should be used with extreme
 * caution on a production system.
 */
public String[] findReloadedContextMemoryLeaks() {

    System.gc();

    List<String> result = new ArrayList<String>();

    for (Map.Entry<ClassLoader, String> entry :
            childClassLoaders.entrySet()) {
        ClassLoader cl = entry.getKey();
        if (cl instanceof WebappClassLoaderBase) {
            if (!((WebappClassLoaderBase) cl).isStarted()) {
                result.add(entry.getValue());
            }
        }
    }

    return result.toArray(new String[result.size()]);
}

@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
        throws ServletException, IOException {
    resp.setContentType("text/plain");
    PrintWriter out = resp.getWriter();

    ClassLoader system = ClassLoader.getSystemClassLoader();

    ClassLoader cl = Thread.currentThread().getContextClassLoader();
    while (cl != null) {
        if (system == cl) {
            out.print("SYSTEM,");
        } else if (custom == cl) {
            out.print("CUSTOM,");
        } else if (cl instanceof WebappClassLoaderBase) {
            out.print("WEBAPP,");
        } else {
            out.print("OTHER,");
        }
        cl = cl.getParent();
    }
}

/**
 * Attempt to identify the contexts that have a class loader memory leak.
 * This is usually triggered on context reload. Note: This method attempts
 * to force a full garbage collection. This should be used with extreme
 * caution on a production system.
 */
public String[] findReloadedContextMemoryLeaks() {

    System.gc();

    List<String> result = new ArrayList<String>();

    for (Map.Entry<ClassLoader, String> entry : childClassLoaders.entrySet()) {
        ClassLoader cl = entry.getKey();
        if (cl instanceof WebappClassLoaderBase) {
            if (!((WebappClassLoaderBase) cl).isStarted()) {
                result.add(entry.getValue());
            }
        }
    }

    return result.toArray(new String[result.size()]);
}

private void checkForRequestThreads(WebappLoader webappLoader) throws Exception {
    Method getThreadsMethod = WebappClassLoaderBase.class.getDeclaredMethod("getThreads");
    getThreadsMethod.setAccessible(true);
    Method isRequestThreadMethod =
            WebappClassLoaderBase.class.getDeclaredMethod("isRequestThread", Thread.class);
    isRequestThreadMethod.setAccessible(true);
    ClassLoader webappClassLoader = webappLoader.getClassLoader();
    Thread[] threads = (Thread[]) getThreadsMethod.invoke(webappClassLoader);
    for (Thread thread : threads) {
        if (thread == null) {
            continue;
        }
        if ((boolean) isRequestThreadMethod.invoke(webappClassLoader, thread)) {
            StringBuilder sb = new StringBuilder();
            for (StackTraceElement element : thread.getStackTrace()) {
                sb.append(element);
                sb.append('\n');
            }
            logger.error("tomcat request thread \"{}\" is still active:\n{}", thread.getName(),
                    sb);
        }
    }
}

private void checkForRequestThreads(WebappLoader webappLoader) throws Exception {
    Method getThreadsMethod = WebappClassLoaderBase.class.getDeclaredMethod("getThreads");
    getThreadsMethod.setAccessible(true);
    Method isRequestThreadMethod =
            WebappClassLoaderBase.class.getDeclaredMethod("isRequestThread", Thread.class);
    isRequestThreadMethod.setAccessible(true);
    ClassLoader webappClassLoader = webappLoader.getClassLoader();
    Thread[] threads = (Thread[]) getThreadsMethod.invoke(webappClassLoader);
    for (Thread thread : threads) {
        if (thread == null) {
            continue;
        }
        if ((Boolean) isRequestThreadMethod.invoke(webappClassLoader, thread)) {
            StringBuilder sb = new StringBuilder();
            for (StackTraceElement element : thread.getStackTrace()) {
                sb.append(element);
                sb.append('\n');
            }
            logger.error("tomcat request thread \"{}\" is still active:\n{}", thread.getName(),
                    sb);
        }
    }
}