Java uses regular expressions to determine whether the incoming data is a number

可以利用正则表达式来“-?[0-9]+(\\.[0-9]+)?”来做判断字符串是否为数字。

如果传入的数据有很多位，那么使用double会导致精度丢失，这个时候就要用BigDecimal来进行转换。

实例：

public class CheckStrIsNum { public static void main(String[] args) { double aa = -192322.1212; String a = "-192322.1212"; String b = "-192322a1212"; String c = "Java"; String d = "5"; /** 判断是否全为数字 */ System.out.println(checkStrIsNum02(Double.toString(aa))); System.out.println(checkStrIsNum02(a)); System.out.println(checkStrIsNum02(b)); System.out.println(checkStrIsNum02(c)); System.out.println(checkStrIsNum02(d)); } private static Pattern NUMBER_PATTERN = Pattern.compile("-?[0-9]+(\\.[0-9]+)?"); /** * 利用正则表达式来判断字符串是否为数字 */ public static boolean checkStrIsNum02(String str) { String bigStr; try { /** 先将str转成BigDecimal，然后在转成String */ bigStr = new BigDecimal(str).toString(); } catch (Exception e) { /** 如果转换数字失败，说明该str并非全部为数字 */ return false; } Matcher isNum = NUMBER_PATTERN.matcher(str); if (!isNum.matches()) { return false; } return true; } }

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