Sun JVM上MBean的CPU使用率（%）

jconsole上进程的overview选项卡显示了CPU使用率百分比。是否有一个MBean给我这个值？它的对象名是什么？

ManagementFactory中似乎没有直接的MBean。最接近的是可以用来计算整个系统使用的CPU

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然而，基于jconsole的源代码，更新：在Java 7中，您可以这样做：

public static double getProcessCpuLoad() throws MalformedObjectNameException, ReflectionException, InstanceNotFoundException {

    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();

    if (value == -1.0)      return Double.NaN;

    return ((int)(value * 1000) / 10.0);        // returns a percentage value with 1 decimal point precision
}

-----原始答案如下-----

在Java 7中，您可以使用

com.sun.management.OperatingSystemMXBean

的隐藏方法：

getProcessCpuLoad()    // returns the CPU usage of the JVM

getSystemCpuLoad()     // returns the CPU usage of the whole system

这两个值都以0.0和1.0之间的双精度形式返回，因此只需乘以100即可得到一个百分比

com.sun.management.OperatingSystemMXBean osBean = ManagementFactory.getPlatformMXBean(OperatingSystemMXBean.class);
System.out.println(osBean.getProcessCpuLoad() * 100);
System.out.println(osBean.getSystemCpuLoad()  * 100);

由于这些方法是隐藏的、未记录的、存在于

com.sun.management.OperatingSystemMXBean

包中的方法，而不存在于

java.lang.management.OperatingSystemMXBean

中，因此它们可能在某些JVM或将来的更新中不可用，因此您应该决定是否愿意承担这种风险

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有关更多信息，请参阅。

我从internet修改了一段代码，如下所示，然后对其进行了测试，结果几乎与linux ps命令的结果一致

/**下面是代码*/

public float getCpuUsed() {

    /** get a MXBean  */
    com.sun.management.OperatingSystemMXBean osMXBean =
    (com.sun.management.OperatingSystemMXBean) 
    ManagementFactory.getOperatingSystemMXBean();


    /** set old timestamp values */
    long previousJvmProcessCpuTime = osMXBean.getProcessCpuTime();


    int sleepTime = 350;
    /** sleep for a while to use to calculate */
    try {
        TimeUnit.MILLISECONDS.sleep(sleepTime);
    } catch (InterruptedException e) {
        logger.error("InterruptedException occurred while MemoryCollector sleeping...");
    }

    /** elapsed process time is in nanoseconds */
    long elapsedProcessCpuTime = osMXBean.getProcessCpuTime() - previousJvmProcessCpuTime;

    /** elapsed uptime is in milliseconds */

    long elapsedJvmUptime = sleepTime ;

    /** total jvm uptime on all the available processors */
    //long totalElapsedJvmUptime = elapsedJvmUptime * osMXBean.getAvailableProcessors() ;
    long totalElapsedJvmUptime = elapsedJvmUptime;
    //System.out.println("echo cpu processors num " + osMXBean.getAvailableProcessors());

    /** calculate cpu usage as a percentage value
       to convert nanoseconds to milliseconds divide it by 1000000 and to get a percentage multiply it by 100 */
    float cpuUsage = elapsedProcessCpuTime / (totalElapsedJvmUptime * 10000F);



    return (float)(Math.round(cpuUsage*10)/10);
}

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如果您使用的是基于UNIX的操作系统，那么就容易多了

final OperatingSystemMXBean mxBean = ManagementFactory.getOperatingSystemMXBean();
if (mxBean instanceof UnixOperatingSystemMXBean) {
  return ((UnixOperatingSystemMXBean) mxBean).getSystemCpuLoad() * 100.0;
}

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这不是我想要的（简单的）解决方案，但似乎是唯一的方法。请注意，演员阵容是com.sun.management.OperatingSystemMXBean！您提供的URL适用于Java 7

com.sun.management.OperatingSystemMXBean

在Java 6中不可访问…注意：这些方法在Java 6中不可用。