判断是否为 数字 小数

public class NumberDemo {public static void main(String[] args) {String str1="1122.2.2";String str2="111";String str3="111.2";String str4="111s";String str5="111.s";String str6="1s11";System.out.println(str1+":"+isNum(str1));System.out.println(str2+":"+isNum(str2));System.out.println(str3+":"+isNum(str3));System.out.println(str4+":"+isNum(str4));System.out.println(str5+":"+isNum(str5));System.out.println(str6+":"+isNum(str6));}public static boolean isNum(String str){return str.matches("^[-+]?(([0-9]+)([.]([0-9]+))?|([.]([0-9]+))?)$");}}结果:1122.2.2:false111:true111.2:true111s:false111.s:false1s11:false