java怎么用正则表达式匹配字符串 使用正则表达式处理文本匹配与提取

String phone = "13812345678";
String regex = "^1[3-9]\d{9}$"; // 匹配以1开头，第二位是3-9，共11位数字
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(phone);

if (matcher.matches()) {
    System.out.println("手机号格式正确");
} else {
    System.out.println("手机号格式错误");
}

String log = "2023-10-05 14:23:11 [INFO] User login from 192.168.1.100";
String regex = "(\d{4}-\d{2}-\d{2})\s(\d{2}:\d{2}:\d{2}).*?(\d+\.\d+\.\d+\.\d+)";
Pattern pattern = Pattern.compile(regex);
Matcher matcher = pattern.matcher(log);

if (matcher.find()) {
    String date = matcher.group(1); // 日期
    String time = matcher.group(2); // 时间
    String ip = matcher.group(3);   // IP地址
    System.out.println("日期：" + date);
    System.out.println("时间：" + time);
    System.out.println("IP：" + ip);
}

String email = "user@example.com";
boolean isValid = email.matches("\w+@\w+\.\w+");
System.out.println(isValid ? "邮箱格式正确" : "邮箱格式错误");