String s = "123.45";
if (s.matches("[+-]?\\d+([.]\\d{2})")) {
    System.out.println("ok");
} else {
    System.out.println("error");
}

------解决方案--------------------
探讨


Java code
String s = "123.45";
if (s.matches("[+-]?\\d+([.]\\d{2})")) {
    System.out.println("ok");
} else {
    System.out.println("error");
}


------解决方案--------------------
借鉴2楼的，稍作了些修改:
Java code

String s = "123.45";
if (s.matches("-?\\d+([.]\\d{2})?")) {
    System.out.println("ok");
} else {
    System.out.println("error");
}

------解决方案--------------------
if(price.matches("/(^[0-9]*$)|(^[0-9]*[.]{1}[0-9]{1,2}$)/")
{
    msg="OK:
}

------解决方案--------------------
探讨


if(price.matches("/(^[0-9]*$)|(^[0-9]*[.]{1}[0-9]{1,2}$)/")
{
     msg="OK";
}