java 判断一个字符串中的数字：是否为数字、是否包含数字、截取数字

[java] view plain copy

 

// 判断一个字符串是否都为数字
public boolean isDigit(String strNum) {
    return strNum.matches("[0-9]{1,}");
}

// 判断一个字符串是否都为数字
public boolean isDigit(String strNum) {
    Pattern pattern = Pattern.compile("[0-9]{1,}");
    Matcher matcher = pattern.matcher((CharSequence) strNum);
    return matcher.matches();
}

//截取数字
public String getNumbers(String content) {
    Pattern pattern = Pattern.compile("\d+");
    Matcher matcher = pattern.matcher(content);
    while (matcher.find()) {
       return matcher.group(0);
    }
    return "";
}

// 截取非数字
public String splitNotNumber(String content) {
    Pattern pattern = Pattern.compile("\D+");
    Matcher matcher = pattern.matcher(content);
    while (matcher.find()) {
        return matcher.group(0);
    }
    return "";
}

// 判断一个字符串是否含有数字
public boolean HasDigit(String content) {
    boolean flag = false;
    Pattern p = Pattern.compile(".*\d+.*");
    Matcher m = p.matcher(content);
    if (m.matches()) {
        flag = true;
    }
    return flag;
}

java中判断字符串是否为数字的三种方法 ：

1.用JAVA自带的函数 

public static boolean isNumeric(String str) {
    for (int i = str.length(); --i >= 0;) {
        if (!Character.isDigit(str.charAt(i))) {
            return false;
        }
    }
    return true;
}

2.用正则表达式 

public static boolean isNumeric(String str) {
    Pattern pattern = Pattern.compile("[0-9]*");
    return pattern.matcher(str).matches();
}

3.用ascii码 

public static boolean isNumeric(String str) {
    for (int i = str.length(); --i >= 0;) {
        int chr = str.charAt(i);
        if (chr < 48 || chr > 57)
            return false;
    }
    return true;
}