Java MemoryPoolMXBean.getPeakUsage方法代碼示例

import java.lang.management.MemoryPoolMXBean; //導入方法依賴的package包/類
/**
 * Returns a summary information about the memory pools.
 */
public static String poolSummaries() {
    // Why ? list-archive?4273859
    // How ? http://stackoverflow.com/questions/697336/how-do-i-programmatically-find-out-my-permgen-space-usage
    //       http://stackoverflow.com/questions/8356416/xxmaxpermsize-with-or-without-xxpermsize
    StringBuilder sb = new StringBuilder();
    Iterator<MemoryPoolMXBean> iter =
            ManagementFactory.getMemoryPoolMXBeans().iterator();
    while (iter.hasNext()) {
        MemoryPoolMXBean item = iter.next();
        String name = item.getName();
        MemoryType type = item.getType();
        MemoryUsage usage = item.getUsage();
        MemoryUsage peak = item.getPeakUsage();
        MemoryUsage collections = item.getCollectionUsage();
        sb.append(String.format("Memory pool name: " + name
                                + ", type: " + type
                                + ", usage: " + usage
                                + ", peak: " + peak
                                + ", collections: " + collections
                                + "\n"));
    }
    return sb.toString();
}
 

import java.lang.management.MemoryPoolMXBean; //導入方法依賴的package包/類
public static JvmStats jvmStats() {
    MemoryUsage memUsage = memoryMXBean.getHeapMemoryUsage();
    long heapUsed = memUsage.getUsed() < 0 ? 0 : memUsage.getUsed();
    long heapCommitted = memUsage.getCommitted() < 0 ? 0 : memUsage.getCommitted();
    long heapMax = memUsage.getMax() < 0 ? 0 : memUsage.getMax();
    memUsage = memoryMXBean.getNonHeapMemoryUsage();
    long nonHeapUsed = memUsage.getUsed() < 0 ? 0 : memUsage.getUsed();
    long nonHeapCommitted = memUsage.getCommitted() < 0 ? 0 : memUsage.getCommitted();
    List<MemoryPoolMXBean> memoryPoolMXBeans = ManagementFactory.getMemoryPoolMXBeans();
    List<MemoryPool> pools = new ArrayList<>();
    for (MemoryPoolMXBean memoryPoolMXBean : memoryPoolMXBeans) {
        try {
            MemoryUsage usage = memoryPoolMXBean.getUsage();
            MemoryUsage peakUsage = memoryPoolMXBean.getPeakUsage();
            String name = GcNames.getByMemoryPoolName(memoryPoolMXBean.getName(), null);
            if (name == null) { // if we can't resolve it, its not interesting.... (Per Gen, Code Cache)
                continue;
            }
            pools.add(new MemoryPool(name,
                    usage.getUsed() < 0 ? 0 : usage.getUsed(),
                    usage.getMax() < 0 ? 0 : usage.getMax(),
                    peakUsage.getUsed() < 0 ? 0 : peakUsage.getUsed(),
                    peakUsage.getMax() < 0 ? 0 : peakUsage.getMax()
            ));
        } catch (Exception ex) {
            /* ignore some JVMs might barf here with:
             * java.lang.InternalError: Memory Pool not found
             * we just omit the pool in that case!*/
        }
    }
    Mem mem = new Mem(heapCommitted, heapUsed, heapMax, nonHeapCommitted, nonHeapUsed, Collections.unmodifiableList(pools));
    Threads threads = new Threads(threadMXBean.getThreadCount(), threadMXBean.getPeakThreadCount());

    List<GarbageCollectorMXBean> gcMxBeans = ManagementFactory.getGarbageCollectorMXBeans();
    GarbageCollector[] collectors = new GarbageCollector[gcMxBeans.size()];
    for (int i = 0; i < collectors.length; i++) {
        GarbageCollectorMXBean gcMxBean = gcMxBeans.get(i);
        collectors[i] = new GarbageCollector(GcNames.getByGcName(gcMxBean.getName(), gcMxBean.getName()),
                gcMxBean.getCollectionCount(), gcMxBean.getCollectionTime());
    }
    GarbageCollectors garbageCollectors = new GarbageCollectors(collectors);
    List<BufferPool> bufferPoolsList = Collections.emptyList();
    try {
        List<BufferPoolMXBean> bufferPools = ManagementFactory.getPlatformMXBeans(BufferPoolMXBean.class);
        bufferPoolsList = new ArrayList<>(bufferPools.size());
        for (BufferPoolMXBean bufferPool : bufferPools) {
            bufferPoolsList.add(new BufferPool(bufferPool.getName(), bufferPool.getCount(),
                    bufferPool.getTotalCapacity(), bufferPool.getMemoryUsed()));
        }
    } catch (Exception e) {
        // buffer pools are not available
    }

    Classes classes = new Classes(classLoadingMXBean.getLoadedClassCount(), classLoadingMXBean.getTotalLoadedClassCount(),
            classLoadingMXBean.getUnloadedClassCount());

    return new JvmStats(System.currentTimeMillis(), runtimeMXBean.getUptime(), mem, threads,
            garbageCollectors, bufferPoolsList, classes);
}