About entering a price question, which is a number greater than 0

Problem premise:

When entering the price, often is not clear is an integer or a decimal, want to finally be when the user input is an integer automatically becomes an integer, the input decimal becomes a decimal, and the price is more than 0 of the number is required, so it is reasonable, the following is my attempt,

using regular Expressions

1. At the beginning, I wrote a method that can be judged as an integer.

/**
* Determine if the integer is greater than 0
*
* @param str
* @return
*/
public static double Isinteger (String str) {
Double result;
Pattern pattern = Pattern.compile ("^1[-\\+]?[ \\d]*$ ");
Pattern pattern = pattern.compile ("^[1-9][\\d]*$");

if (!pattern.matcher (str). Matches ()) {
SYSTEM.OUT.PRINTLN ("You entered is not a number or illegal, please re-enter a number greater than 0!") ");
Scanner sc = new Scanner (system.in);
result = Isinteger (Sc.next ());
} else {
result = Double.parsedouble (str);
}

return result;
}

OK, able to cope with a variety of non-and hair input

2. When you add a decimal that can be judged,

public static double Isdata (String str) {
Double result = 0;
Scanner SC =new Scanner (system.in);
Pattern pattern = pattern.compile ("^[1-9][\\d]*$");
Pattern pattern2 = Pattern.compile ("^[0-9]+.*[0-9]*");
if (".". Equals (str)) {
SYSTEM.OUT.PRINTLN ("You entered is not a number or illegal, please re-enter a number greater than 0!") ");
}else
if (!pattern.matcher (str). Matches ()) {
if (!pattern2.matcher (str). Matches ()) {
SYSTEM.OUT.PRINTLN ("You entered is not a number or illegal, please re-enter a number greater than 0!") ");
result = Isdata (Sc.next ());
}else{
result = Double.parsedouble (str);
}
}else{
result = Integer.parseint (str);
}

return result;
}

It looks like it's gone, but it's still not working.

Especially when you enter 23-2 or 22\22, you hang up.

3. Last Word online swing one

Using a regular expression to determine whether a string is a number, this way to judge the surface comparison is full//can be judged positive and negative, integer decimal boolean strresult = Str.matches ("-?[ 0-9]+.*[0-9]* "), if (strresult = = True) {System.out.println (" is number! "),} else {System.out.println (" is not number! ");}

for this question, I finally chose the Java's self-bringing approach

public static void Main (string[] args) {
String a= "null";
Isdilg ();
}
/**
* Determine whether to enter an integer or decimal number greater than 0
*/
public static void Isdilg () {
int i=0;
Double d = null;
System.out.println ("\ n sdf");
Scanner SC =new Scanner (system.in);
do{
int a=-2;
if (!sc.hasnextint ()) {
if (!sc.hasnextdouble ()) {
System.out.println ("------------");
SYSTEM.OUT.PRINTLN ("You entered the illegal, please re-enter!") ");
Isdilg ();
}else{
D=sc.nextdouble ();
if (d>0) {
System.out.println (d);
}else{
SYSTEM.OUT.PRINTLN ("You entered the illegal, please re-enter!") ");
Isdilg ();
}
}
}else{
I=sc.nextint ();
if (i>0) {
System.out.println (i);
}else{
SYSTEM.OUT.PRINTLN ("You entered the illegal, please re-enter!") ");
Isdilg ();
}
}
}while (TRUE);
}

Yes, OK, no killing, or someone else Java method Good, this is really not a regular expression is not very useful, and consider not the whole classmate,

Or with the Java API simple!

About entering a price question, which is a number greater than 0