解析NULL 为 空字符

https://www.baidu.com/s?wd=JSON%20document%20was%20not%20fully%20consumed.&rsv_spt=1&rsv_iqid=0x92fdf06b000038ba&issp=1&f=8&rsv_bp=1&rsv_idx=2&ie=utf-8&rqlang=cn&tn=98012088_5_dg&ch=12&rsv_enter=0&oq=gson%2520%25E8%2587%25AA%25E5%25AE%259A%25E4%25B9%2589%25E8%25A7%25A3%25E6%259E%2590%2520reader.peek()%2520%25E8%25A7%25A3%25E5%2586%25B3&rsv_t=d2fbhc%2FPo1G32D%2BtCw%2F2dGh8OoKLMPdj6jZLv%2F0p1X4fJjl79nnPLmbMU9QuGL%2FjHp49%2Bw&inputT=1051538&rsv_pq=b8a9b34400005b29&rsv_sug3=47&rsv_n=2&rsv_sug4=1052590&rsv_sug=1

http://www.jianshu.com/p/8cc857583ff4

https://www.cnblogs.com/linjzong/p/5201565.html

https://www.cnblogs.com/linjzong/p/5201565.html

http://blog.youkuaiyun.com/axuanqq/article/details/51441590

http://www.jianshu.com/p/8cc857583ff4

http://www.cnblogs.com/zhangminghui/p/4109539.html

https://www.cnblogs.com/wytings/p/6195068.html

https://github.com/alibaba/fastjson