json中属性带点号怎么得到其中的值

这个是json结构tostring后的结果:
{"SUCCESS":{"TYPE":"SUCCESS","RESULTS":{"COUNT":"2","SEQ":"1,2"},"RESULTS.1":{"ENDCOL":"","FILL":"512","COLFLAG":"NULL","ROWFLAG":"NULL"},"RESULTS.2":{"ENDCOL":"YES","FILL":"","COLFLAG":"|","ROWFLAG":"CRLF"}}比如说我要得到SUCCESS下RESULTS.1中的FILL属性的值，要怎么写才能得到呢？求高手指点！