Java驗證是否為純數字

package rbq.codedemo;

import java.util.regex.Pattern;

/**
 * Created by rbq on 2016/12/13.
 */

public class NumUtils {

 public static boolean isNum(String str){

 Pattern pattern = Pattern.compile("^-?[0-9]+");
 if(pattern.matcher(str).matches()){
 //數字
 return true;
 } else {
 //非數字
 return false;
 }
 }

 public static boolean isNum1(String str){
 //帶小數的
 Pattern pattern = Pattern.compile("^[-+]?[0-9]+(\\.[0-9]+)?$");

 if(pattern.matcher(str).matches()){
 //數字
 return true;
 } else {
 //非數字
 return false;
 }
 }

}