Map使用操作系统内存的情况

    public static void main(String[] args) {

        System.out.println("程序启动-->可用内存:"+(getSystemMem()/1024/1024)+"M");
        Long systemMem = getSystemMem();
        Map<byte[],Byte> map = new HashMap<byte[], Byte>();
        for(int i=0;i<100000000;i++){
            map.put(StringUtils.md5("http://www.baidu.com"+i),Byte.parseByte("1"));
            if(i%100000==99999){
                System.out.println("存储"+(i+1)+"后，使用内存:"+((systemMem-getSystemMem())/1024/1024)+"M");
            }
        }
    }

    public static Long getSystemMem(){
         OperatingSystemMXBean osmb = (OperatingSystemMXBean) ManagementFactory.getOperatingSystemMXBean();
         return osmb.getFreePhysicalMemorySize();
    }