使用mbean 自动执行heap dump

记录下如何查看mbean的使用方法和自动进行heap dump。

import java.io.File;
import java.lang.management.ManagementFactory;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.management.InstanceNotFoundException;
import javax.management.IntrospectionException;
import javax.management.MBeanException;
import javax.management.MBeanOperationInfo;
import javax.management.MBeanServer;
import javax.management.MalformedObjectNameException;
import javax.management.ObjectName;
import javax.management.ReflectionException;

public class HeapDump {
    

    //https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/DiagnosticCommandMBean.html
	public static final String DIAGNOSTIC_COMMAND = "com.sun.management:type=DiagnosticCommand";
    private static final String HEAP_COMMAND = "gcClassHistogram";

    //can be useful for dumping heaps in binary format
    //https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/HotSpotDiagnosticMXBean.html
    public static final String HOTSPOT_DIAGNOSTIC = "com.sun.management:type=HotSpotDiagnostic";
    private static final String DUMP_COMMAND = "dumpHeap";
    private static final String DUMP_FILE_NAME = "heap";
    private static final String DUMP_FILE_ENDING = ".hprof";
    private static final boolean DUMP_DEAD_OBJECTS = false;

    private static final DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");

    public static void dumpHeap(String dumpFolder)
            throws MalformedObjectNameException, InstanceNotFoundException, MBeanException, ReflectionException {
    
        MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
        ObjectName hotspotBean = ObjectName.getInstance(HOTSPOT_DIAGNOSTIC);

        String timeSuffix = '-' + dateFormat.format(new Date());
        File dumpFile = new File(dumpFolder, DUMP_FILE_NAME + timeSuffix + DUMP_FILE_ENDING);
        //it needs to be with a system dependent path seperator
        mBeanServer.invoke(hotspotBean, DUMP_COMMAND
                , new Object[]{
    dumpFile.getAbsolutePath(), DUMP_DEAD_OBJECTS}
                , new String[]{
    String.class.getName(), Boolean.TYPE.getName()});
    }

    
    /** * 打印mbean 使用方式 * HeapDump.getMBeanInfo(HeapDump.DIAGNOSTIC_COMMAND); * HeapDump.getMBeanInfo(HeapDump.HOTSPOT_DIAGNOSTIC); * @param mbeanName * @throws MalformedObjectNameException * @throws NullPointerException * @throws IntrospectionException * @throws InstanceNotFoundException * @throws ReflectionException */
    public static void getMBeanInfo(String mbeanName) throws MalformedObjectNameException, NullPointerException, IntrospectionException, InstanceNotFoundException, ReflectionException {
    
	MBeanServer server = ManagementFactory.getPlatformMBeanServer();
	  ObjectName hotspotBean = ObjectName.getInstance(mbeanName);
	  javax.management.MBeanInfo mbeanInfo = server.getMBeanInfo(hotspotBean);
	  MBeanOperationInfo[] operations = mbeanInfo.getOperations();
	  for (int i=0;i<operations.length;i++) {
    
		  System.out.println(operations[i].toString());
	  }
    }
	
	
    public static void getHeap()
            throws MalformedObjectNameException, InstanceNotFoundException, MBeanException, ReflectionException {
    
                    ObjectName diagnosticObjectName = ObjectName.getInstance(DIAGNOSTIC_COMMAND);

        MBeanServer mBeanServer = ManagementFactory.getPlatformMBeanServer();
        String reply = (String) mBeanServer.invoke(diagnosticObjectName, HEAP_COMMAND
                , new Object[]{
    new String[]{
    }}, new String[]{
    String[].class.getName()});
        System.out.println(reply);
    }
}

以上代码核心来源：
https://gist.githubusercontent.com/munendrasn/2b67831b7a62d4db90c12467466a9736/raw/0679a2bb54f56a416b71912b8890a2473b336a75/HeapDump.java