检查String是否包含Java中的数字值

Question

如何编写一个方法来查找给定字符串是否包含数字？如果字符串包含数字,则该方法应返回true,否则返回false.

Answer 1

if(str.matches(".*\\d.*")){
   // contains a number
} else{
   // does not contain a number
}

以前建议的解决方案,但不起作用,但由于@ Eng.Fouad的请求/建议而退回.

不工作建议的解决方案

String strWithNumber = "This string has a 1 number";
String strWithoutNumber = "This string does not have a number";

System.out.println(strWithNumber.contains("\d"));
System.out.println(strWithoutNumber.contains("\d"));

工作方案

String strWithNumber = "This string has a 1 number";
if(strWithNumber.matches(".*\\d.*")){
    System.out.println("'"+strWithNumber+"' contains digit");
} else{
    System.out.println("'"+strWithNumber+"' does not contain a digit");
}

String strWithoutNumber = "This string does not have a number";
if(strWithoutNumber.matches(".*\\d.*")){
    System.out.println("'"+strWithoutNumber+"' contains digit");
} else{
    System.out.println("'"+strWithoutNumber+"' does not contain a digit");
}

产量

'This string has a 1 number' contains digit
'This string does not have a number' does not contain a digit

Answer 2

使用循环 -

public static boolean containsDigit(final String aString)
{
    if (aString != null && !aString.isEmpty())
    {
        for (char c : aString.toCharArray())
        {
            if (Character.isDigit(c))
            {
                return true;
            }
        }
    }

    return false;
}

使用流 -

public static boolean containsDigit(final String aString)
{
    return aString != null && !aString.isEmpty() &&
            aString.chars().anyMatch(Character::isDigit);
}

Answer 3

谢夫的答案不适合我.看起来他正在使用RegEx String.contains().如果你想使用RegEx,请使用:

String strWithNumber = "This string has a 1 number";
String strWithoutNumber = "This string has a number";

System.out.println(strWithNumber.matches(".*\\d.*"));
System.out.println(strWithoutNumber.matches(".*\\d.*"));

Answer 4

您可以使用正则表达式来查明字符串是否包含数字。看看matches()方法吧。