java使用split分隔，需要注意的点

String severName = "10.6.62.244";
System.out.println(severName.split(".").length);//----0
System.out.println(severName.split("\\.").length);//----4
String str = "22,33,2,,,,";
System.out.println(str.split(",").length);//----3
str += " ";
System.out.println(str.split(",").length);//----7