java 判斷字符串是否為數字(包含負數)

public static void main(String[] args){
   System.out.println(AssistController.isNumeric("-77"));
}

public static boolean isNumeric(String str){
    Pattern pattern = Pattern.compile("-?[0-9]+(.[0-9]+)?");
    Matcher isNum = pattern.matcher(str);
    if( !isNum.matches() ){
        return false;
    }
    return true;
}