java代码通过端口号拿到MemoryPoolMXBeans

可以使用以下的Java代码通过端口号拿到MemoryPoolMXBeans：

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.SocketChannel;
import java.util.List;

import javax.management.MBeanServerConnection;
import javax.management.ObjectName;
import javax.management.remote.JMXConnector;
import javax.management.remote.JMXConnectorFactory;
import javax.management.remote.JMXServiceURL;
import javax.management.remote.rmi.RMIConnector;

import com.sun.management.HotSpotDiagnosticMXBean;
import com.sun.management.HotSpotDiagnosticMXBean.DumpReason;
import com.sun.management.VMOption;

public class MemoryPoolMXBeanClient {

    public static void main(String[] args) throws Exception {
        int portNumber = 9999;
        String hostName = "localhost";
        String url = "service:jmx:rmi:///jndi/rmi://" + hostName + ":" + portNumber + "/jmxrmi";
        JMXServiceURL serviceUrl = new JMXServiceURL(url);
        JMXConnector jmxConnector = JMXConnectorFactory.connect(serviceUrl);
        MBeanServerConnection mbeanServerConnection = jmxConnector.getMBeanServerConnection();
        
        ObjectName memoryPoolMXBeansObjectName = new ObjectName("java.lang:type=MemoryPool,*");
        List<ObjectName> memoryPoolMXBeans = mbeanServerConnection.queryNames(memoryPoolMXBeansObjectName, null);
        
        for (ObjectName objName : memoryPoolMXBeans) {
            System.out.println(objName);
        }
        
        jmxConnector.close();
    }
}

这个程序会连接到指定的端口号上，然后从中获取`MemoryPoolMXBeans`。