java分组正则表达式无法匹配字符串+文本

Question

我写了这个测试

@Test
public void removeRequestTextFromRouteError() throws Exception {
    String input = "Failed to handle request regression_4828 HISTORIC_TIME from=s:33901510 tn:27825741 bd:false st:Winifred~Dr to=s:-1 d:false f:-1.0 x:-73.92752 y:40.696857 r:-1.0 cd:-1.0 fn:-1 tn:-1 bd:true 1 null false null on subject RoutingRequest";
    final String answer = stringUtils.removeRequestTextFromError(input);
    String expected = "Failed to handle request _ on subject RoutingRequest";
    assertThat(answer, equalTo(expected));
}

运行此方法，但失败

public String removeRequestTextFromError(String answer) {
    answer = answer.replaceAll("regression_\\d\\[.*?\\] on subject", "_ on subject");
    return answer;

}

输入文本保持不变，不替换为“_”

如何更改模式匹配来解决此问题？

Answer 1

您使用了错误的正则表达式。您正在转义 [ 和 ] (根本没有必要)并使用 \\d 而不是 \\d+ 。另外，您应该使用积极的前瞻，而不是实际选择和替换字符串“on subject”

用途:

public static void main(String[] args) {
    String input = "Failed to handle request regression_4828 HISTORIC_TIME from=s:33901510 tn:27825741 bd:false st:Winifred~Dr to=s:-1 d:false f:-1.0 x:-73.92752 y:40.696857 r:-1.0 cd:-1.0 fn:-1 tn:-1 bd:true 1 null false null on subject RoutingRequest";
    final String answer = input.replaceAll("regression_.* (?=on subject)", "_ ");
    System.out.println(answer);
    String expected = "Failed to handle request _ on subject RoutingRequest";
    System.out.println(answer.equals(expected));
}

操作:

Failed to handle request _ on subject RoutingRequest
true