casting(kalıba dökme), istisna yakalama, regex, character digit kontrolü, number format parsing dir. casting: [code language=”java”] if (x == (int)x) { // Number is integer } [/code] catching integer: [code language=”java”] public static boolean isInteger(String s) { try { Integer.parseInt(s); } catch(NumberFormatException e) { return false; } return true; } [/code] catching double: [code language=”java”] public static boolean isNumeric(String str) { try { double d = Double.parseDouble(str); } catch(NumberFormatException nfe) { return false; } return true; } [/code] regex: [code language=”java”] public static boolean isNumeric(String str) { return str.matches("-?\\d+(\\.\\d+)?"); //match a number with optional ‘-‘ and decimal. } [/code] number format parsing: [code language=”java”] public static boolean isNumeric(String str) { NumberFormat formatter = NumberFormat.getInstance(); ParsePosition pos = new ParsePosition(0); formatter.parse(str, pos); return str.length() == pos.getIndex(); } [/code] character digit control: [code language=”java”] public static boolean isInteger(String s) { return isInteger(s,10); } public static boolean isInteger(String s, int radix) { if(s.isEmpty()) return false; for(int i = 0; i < s.length(); i++) { if(i == 0 && s.charAt(i) == ‘-‘) { if(s.length() == 1) return false; else continue; } if(Character.digit(s.charAt(i),radix) < 0) return false; } return true; } [/code]]]>