java - 我可以在具有以下条件的 java 中为以下字符串获取适当的正则表达式吗

Question

测试字符串是

It is a test data
%Warning: portfast should only be enabled on ports connected to a single
 host. Connecting hubs, concentrators, switches, bridges, etc. to this
 interface when portfast is enabled can cause temporary bridging loops.
 Use with CAUTION
Test is a test.

如果字符串中有% 符号，则该字符串无效。但如果 % 后跟以下字符序列，则它是有效的，“%Warning: portfast should only be enabled on ports connected to a single\n host. Connecting hubs, concentrators, switches, bridges等在启用 portfast 时\n 到此接口(interface)可能会导致临时桥接循环。\n 请谨慎使用。即使在这种情况下，“%”符号也只能出现一次。

我的代码是:

public class Abc {

    public static void main(String[] args) {
        String reg="%(Warning: portfast should only be enabled on ports connected to a single\n host. Connecting hubs, concentrators, switches, bridges, etc. to this\n interface when portfast is enabled can cause temporary bridging loops.\n Use with CAUTION)([^%])";
        String str = "%Warning: portfast should only be enabled on ports connected to a single\n host. Connecting hubs, concentrators, switches, bridges, etc. to this\n interface when portfast is enabled can cause temporary bridging loops.\n Use with CAUTIONTest is a testData is invalid%";
        Pattern regEx2 = Pattern
                .compile(reg);
        Matcher matcher = regEx2.matcher(str);
        if (matcher.find()) {
            System.out.println("valid");
        } else {
            System.out.println("invalid");
        }
    }
}

但我没有得到预期的结果。我可以获得合适的正则表达式吗？

Answer 1

也许您可以将您的代码与另一个获取“%”计数的表达式组合在一起

 public static void main(String[] args) {
     String reg = "%Warning: portfast should only be enabled on ports connected to a single\n host. Connecting hubs, concentrators, switches, bridges, etc. to this\n interface when portfast is enabled can cause temporary bridging loops.\n Use with CAUTION";
     String str = "%Warning: portfast should only be enabled on ports connected to a single\n host. Connecting hubs, concentrators, switches, bridges, etc. to this\n interface when portfast is enabled can cause temporary bridging loops.\n Use with CAUTIONTest is a testData is invalid%";
     Pattern regEx2 = Pattern.compile(reg);
     Matcher matcher = regEx2.matcher(str);
     int occurences = str.length() - str.replace("%", "").length();

     if (matcher.find() && occurences <= 1) {
        System.out.println("valid");
     } else {
        System.out.println("invalid");
     }

 }

如果您有 StringUtils 类，那么您可以使用它的方法 countMatches