aav77%%(?<str>([a-zA-Z0-9])){  "str": [    [      "a"    ]  ]}+ 匹配前導字符一次或多次aav77%%(?<str>([a-zA-Z0-9]+)){  "str": [    [      "aav77"    ]  ]}下面是從官方文件中摘抄的最簡單但是足夠說明用法的示例：+USERNAME [a-zA-Z0-9._-]+USER %{USERNAME}aav.%%_(?<str>([a-zA-Z0-9._-]+)){  "str": [    [      "aav."    ]  ]}aavssrr_%%_(?<str>(%{USERNAME})){  "str": [    [      "aavssrr_"    ]  ]}