Main package: snmp4j
Popularization of basic knowledge:
http://www.cnblogs.com/xdp-gacl/p/4187089.html
Complete demo:
http://avery-leo.iteye.com/blog/213980
Detailed explanation of snmp protocol:
http://blog.csdn.net/u010566813/article/details/50490858
http://blog.csdn.net/shanzhizi/article/details/11606767
Courseware
https://wenku.baidu.com/view/3862136127d3240c8447ef19.html