关于java:java代码获取内存信息

一、获取堆外内存

    @GetMapping("/panama")    public Map<String, Object> panama() {        ByteBuffer buffer = ByteBuffer.allocateDirect(1 * 1024 * 1024);        Map<String, Object> map = new HashMap<>();        try {            MBeanServer mbs = ManagementFactory. getPlatformMBeanServer() ;        ObjectName objectName = new ObjectName("java.nio:type=BufferPool,name=direct" ) ;        MBeanInfo info = mbs.getMBeanInfo(objectName) ;               for(MBeanAttributeInfo i : info.getAttributes()) {            map.put(i.getName(), mbs.getAttribute(objectName , i.getName()));        }        } catch (Exception e) {            map.put("error", e);        }        return map;            }

输入后果

Name:directCount:1TotalCapacity:1048576MemoryUsed:1048576ObjectName:java.nio:type=BufferPool,name=direct