Java 键，除非您想保存一些常规的key=value对正则表达式，如？[^ |]+\\s*=\\s*？[^ |]+，然后通过比较建立的键和传递的键来测试每个匹配项。 String s = "a=xxx|b = yyy|c= zzz" static String

键，除非您想保存一些常规的key=value对正则表达式，如？[^ |]+\\s*=\\s*？[^ |]+，然后通过比较建立的键和传递的键来测试每个匹配项。

String s = "a=xxx|b = yyy|c= zzz"

static String getValueFromKey(String s, String key) {
  return s.replaceAll(key + "\\s*=\\s*(.*?)(\\|)?.*", "$1");
}

static void test() {
  String s = "a=xxx|b = yyy|c= zzz";
  assertEquals(getValueFromKey(s, "a"), "xxx");
  assertEquals(getValueFromKey(s, "b"), "yyy");
  assertEquals(getValueFromKey(s, "c"), "zzz");
}

X\s*=\s*(\w*)

\bapple\b\s*=\s*(\w*)

\W*(\w+)\W*=\W*([^|]*)

static void test() {
      String s = "a=xxx|b = yyy|c= zzz";
      Pattern pattern = Pattern.compile("\\W*(\\w+)\\W*=\\W*([^|]*)");
      Matcher matcher = pattern.matcher(s);

      while (matcher.find()) {
          System.out.println(matcher.group(1) + " :: " + matcher.group(2));
      }
    }
}

a :: xxx
b :: yyy
c :: zzz

static String getValueFromKey(String s, String key) {
  string[] pairs = s.split("|");
  for (String p : pairs) {
      string[] halves = p.split("=");
      if (halves[0].equals(key)) {
          return halves[1];
      }
  }

  return "";
}

s.replaceAll(".*?\\b" + key + "\\s*=\\s*(.*?)($|\\|.*)", "$1");

static String getValueFromKey(String s, String key) {
    Matcher m = Pattern.compile(
            "(?<=^|\\|)\\s*" + Pattern.quote(key) + "\\b\\s*=\\s*(?<value>[^|]*)")
            .matcher(s);
    if (m.find())
        return m.group("value");
    else
        return null;// or maybe return empty String "" but that may be misleading 
                    // for values which are really empty Strings
}