Java正则表达式

捕获组

public static void main(String[] args) {
    // 按指定模式在字符串查找
    String line = "This order was placed for QT3000! OK?";
    String pattern = "(\\D*)(\\d+)(.*)";    // `\D` 非数字匹配,等价于[^0~9]

    // 创建 Pattern 对象
    Pattern r = Pattern.compile(pattern);

    // 现在创建 matcher 对象
    Matcher m = r.matcher(line);
    System.out.println("查询结果一共有" + m.groupCount() + "组");
    if (m.find()) {
        /*group(0)是完整目标串自身*/
        System.out.println("Found value: " + m.group(0));
        System.out.println("Found value: " + m.group(1));
        System.out.println("Found value: " + m.group(2));
        System.out.println("Found value: " + m.group(3));
    } else
        System.out.println("NO MATCH");
}