Diagnostics.java 文件源码

/**
 * Get CPU Load of Host System
 *
 * @author http://stackoverflow.com/questions/18489273/how-to-get-percentage-of-cpu-usage-of-os-from-java
 */
private double getCpuLoad() {
    try {
        MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
        ObjectName name = ObjectName.getInstance("java.lang:type=OperatingSystem");
        AttributeList list = mbs.getAttributes(name, new String[]{"ProcessCpuLoad"});

        if (list.isEmpty())
            return Double.NaN;

        Attribute att = (Attribute) list.get(0);
        Double value = (Double) att.getValue();

        // usually takes a couple of seconds before we get real values
        if (value == -1.0)
            return Double.NaN;
        // returns a percentage value with 1 decimal point precision
        return ((int) (value * 1000) / 10.0);
    } catch (Exception e) {
        return Double.NaN;
    }
}