1.http://wenku.baidu.com/link?url=O05r69TGaLmrJrjJqGz-5EASox8FhhUO6i97xoUOV2dcbh8BEnOlX2EN3nuYGE_3HEYOiYUaUTynMICWFP2iuOZBOeRtkmTnVU4w8B-Ko_C&qq-pf-to=pcqq.c2c
2.http://blog.csdn.net/xiaochunyong/article/details/7764683
