/**
 * 获取当前Java进程的活动线程数
 * @return
 */
public Map<String, Object> getThreadsTotal() {
    Map<String, Object> threadDataMap = new HashMap<String, Object>();

    Integer currentThreadCount = 0;
    Integer currentThreadsBusy = 0;

    MBeanServer mbeanServer = ManagementFactory.getPlatformMBeanServer();
    List<ObjectName> threadPools = new ArrayList<ObjectName>();
    try {
        threadPools.addAll(mbeanServer.queryNames(new ObjectName("*:type=ThreadPool,*"), null));

        for (final ObjectName threadPool : threadPools) {
            //获取所有线程池下的线程总数
            currentThreadCount += (Integer) mbeanServer.getAttribute(threadPool, "currentThreadCount");
            currentThreadsBusy += (Integer) mbeanServer.getAttribute(threadPool, "currentThreadsBusy");

        }
    } catch (MalformedObjectNameException e) {
        logger.error("Get threads information error.", e);
    } catch (ReflectionException e) {
        logger.error("Reflecttion error", e);
    } catch (InstanceNotFoundException e) {
        logger.error("Instance not found error.", e);
    } catch (MBeanException e) {
        logger.error("Mean error", e);
    } catch (AttributeNotFoundException e) {
        logger.error("Could not get attribute", e);
    }

    threadDataMap.put("currentThreadCount", currentThreadCount);
    threadDataMap.put("currentThreadsBusy", currentThreadsBusy);

    return threadDataMap;
}

/**
 * 获得Tomcat的内存信息
 * @return
 */
private Map<String, Object> getMemoryInfo() {
    Map<String, Object> memDataMap = new HashMap<String, Object>();

    double MB = 1024.0 * 1024.0;

    //当前JVM的最大可用内存
    double maxMemory = (Runtime.getRuntime().maxMemory()) / MB;

    //当前JVM占用的内存总数
    double totalMemory = (Runtime.getRuntime().totalMemory()) / MB;

    //因为JVM只有在需要内存时才占用物理内存使用，所以freeMemory()的值一般情况下都很小
    double freeMemory = (Runtime.getRuntime().freeMemory()) / MB;

    //JVM实际可用内存
    double totalUsableMemory = maxMemory - totalMemory + freeMemory;

    memDataMap.put("totalUsableMemory", totalUsableMemory);
    memDataMap.put("totalMemory", totalMemory);
    memDataMap.put("maxMemory", maxMemory);

    NumberFormat nt = NumberFormat.getPercentInstance();
    nt.setMinimumFractionDigits(2);
    memDataMap.put("memUsage", nt.format(totalMemory / maxMemory));

    return memDataMap;
}