java.rmi.ConnectException: Connection refused to host: 192.168.1.xxx; nested exception is:
 java.net.ConnectException: Connection timed out: connect


-Dcom.sun.management.jmxremote.ssl=false  
-Dcom.sun.management.jmxremote.authenticate=false  


-Djava.rmi.server.hostname=192.168.1.xxx 
-Dcom.sun.management.jmxremote.port=9988  
-Dcom.sun.management.jmxremote.rmi.port=9988


注意参数 com.sun.management.jmxremote.rmi.port 
JMX is base on RMI, which open two port when it start. 
两个端口可设置成一样

防火墙开放端口

 centos7防火墙配置