indexOf返回值问题

  

String s  = "aoood";
System.out.println(s.indexOf(""));//返回0
System.out.println(s.indexOf("w"));//返回-1
 
 
例如
var customerKinds="GR,QY";
（customerKinds.indexOf(customerKind）!= -1){
    --------------------------------------------------------------
}
customerKind="''" 则会全部显示       customerKind有值，则会根据值显示