logic for the conditions in "if "

if(class1.getMethod1().subString(0,1) == "1") && !class1.getMethod1().subString(0,1).equalsIgnoreCase(str1.subString(0,1)(shld be 1 or 2 or 3 )

i.e., String value is 1 or 2 or 3, then I should skip the if condition I am not able to give

!class1.getMethod1().subString(0,1).equalsIgnoreCase(str1.subString(0,1) == 1 or 2 or 3

Can someone help me with appropriate logic ?