通过java代码查看jvm虚拟情况

最新推荐文章于 2023-06-24 15:42:54 发布

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最新推荐文章于 2023-06-24 15:42:54 发布

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本文链接：https://blog.youkuaiyun.com/pink_s/article/details/102580451

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本文介绍如何利用Java内置的management包，深入查看JVM的运行情况，包括内存使用、线程状态等，以进行性能分析和调优。

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使用的 management的包性能比较强大

 System.out.println("=======================通过java来获取相关系统状态============================ ");
        int i = (int) Runtime.getRuntime().totalMemory() / 1024;//Java 虚拟机中的内存总量,以字节为单位
        System.out.println("总的内存量 i is " + i);
        int j = (int) Runtime.getRuntime().freeMemory() / 1024;//Java 虚拟机中的空闲内存量
        System.out.println("空闲内存量 j is " + j);
        System.out.println("最大内存量 is " + Runtime.getRuntime().maxMemory() / 1024);


        System.out.println("=======================获取整个虚拟机内存使用情况============================ ");
        MemoryMXBean mm = (MemoryMXBean) ManagementFactory.getMemoryMXBean();
        System.out.println("getHeapMemoryUsage " + mm.getHeapMemoryUsage());
        System.out.println("getNonHeapMemoryUsage " + mm.getNonHeapMemoryUsage());

        System.out.println("=======================获取各个线程的各种状态，CPU 占用情况，以及整个系统中的线程状况============================ ");
        ThreadMXBean tm = (ThreadMXBean) ManagementFactory.getThreadMXBean();
        System.out.println("getThreadCount " + tm.getThreadCount());
        System.out.println("getPeakThreadCount " + tm.getPeakThreadCount());
        System.out.println("getCurrentThreadCpuTime " + tm.getCurrentThreadCpuTime());
        System.out.println("getDaemonThreadCount " + tm.getDaemonThreadCount());
        System.out.println("getCurrentThreadUserTime " + tm.getCurrentThreadUserTime());


        System.out.println("=======================当前编译器情况============================ ");
        CompilationMXBean gm = (CompilationMXBean) ManagementFactory.getCompilationMXBean();
        System.out.println("getName " + gm.getName());
        System.out.println("getTotalCompilationTime " + gm.getTotalCompilationTime());


        System.out.println("=======================获取多个内存池的使用情况============================ ");
        List<MemoryPoolMXBean> mpmList = ManagementFactory.getMemoryPoolMXBeans();
        for (MemoryPoolMXBean mpm : mpmList) {
            System.out.println("getUsage " + mpm.getUsage());
            System.out.println("getMemoryManagerNames " + mpm.getMemoryManagerNames().toString());
        }

        System.out.println("=======================获取GC的次数以及花费时间之类的信息============================ ");
        List<GarbageCollectorMXBean> gcmList = ManagementFactory.getGarbageCollectorMXBeans();
        for (GarbageCollectorMXBean gcm : gcmList) {
            System.out.println("getName " + gcm.getName());
            System.out.println("getMemoryPoolNames " + gcm.getMemoryPoolNames());
        }

        System.out.println("=======================获取运行时信息============================ ");
        RuntimeMXBean rmb = (RuntimeMXBean) ManagementFactory.getRuntimeMXBean();
        System.out.println("getClassPath " + rmb.getClassPath());
        System.out.println("getLibraryPath " + rmb.getLibraryPath());
        System.out.println("getVmVersion " + rmb.getVmVersion());