问监视java本机内存

EN

import javax.management.JMException;
import javax.management.ObjectName;
import java.lang.management.ManagementFactory;

public class DiagnosticCommand {

    public static String execute(String command, String... args) throws JMException {
        return (String) ManagementFactory.getPlatformMBeanServer().invoke(
                new ObjectName("com.sun.management:type=DiagnosticCommand"),
                command,
                new Object[]{args},
                new String[]{"[Ljava.lang.String;"});
    }

    public static void main(String[] args) throws Exception {
        String summary = DiagnosticCommand.execute("vmNativeMemory", "summary");
        System.out.println(summary);
    }
}

//Metaspace
for (MemoryPoolMXBean memoryMXBean : ManagementFactory.getMemoryPoolMXBeans()) {
    if ("Metaspace".equals(memoryMXBean.getName())) {
            System.out.println(memoryMXBean.getUsage().getUsed());
            System.out.println(memoryMXBean.getUsage().getCommitted());
            System.out.println(memoryMXBean.getUsage().getMax());
            System.out.println(memoryMXBean.getUsage().getInit());
    }
}

//current number of live threads including both daemon and non-daemon threads
int threadCount = ManagementFactory.getThreadMXBean().getThreadCount();

//Returns the current memory usage of the heap and non-heap
MemoryMXBean memoryMXBean = ManagementFactory.getMemoryMXBean();
MemoryUsage heapMemory = memoryMXBean.getHeapMemoryUsage();
MemoryUsage nonHeapMemory = memoryMXBean.getNonHeapMemoryUsage();

//GarbageCollector total number of collections
List<GarbageCollectorMXBean> garbageCollectorMXBeans = ManagementFactory.getGarbageCollectorMXBeans();
long totalCollectionCount = garbageCollectorMXBeans.stream().mapToLong(x -> x.getCollectionCount()).sum();