使用正则表达式从字符串中提取IP地址

理查德的链接帮助我找到了答案。这是工作代码：

String IPADDRESS_PATTERN =         "(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)";Pattern pattern = Pattern.compile(IPADDRESS_PATTERN);Matcher matcher = pattern.matcher(ipString);if (matcher.find()) {    return matcher.group();} else{    return "0.0.0.0";}