Java 判断映射值是否包含特定字符串和受限列表中的元素

您可以在 map 的值上创建一个流，并对其应用filter()操作两次:

• 找出代码中的目标字符串("A")是否包含在映射值中；
• 以确定特定 map 值与给定限制列表之间是否存在交集.

这两张支票都是anyMatch()美元.

为了提高判断受限列表的性能，它被包装成了HashSet.

通过对每个值执行一次split()操作来创建字符串数组，以减少开销.

目标值("A")、错误消息和分隔符(";")被动态地传递给方法，而不是硬编码.

代码可能如下所示:

public static List<String> getErrorList(List<String> restricted,
                                        Map<String, String> map,
                                        String targetValue, // in your code "A"
                                        String errorMessage,
                                        String delimiter) {
    
    Set<String> restrictedSet = new HashSet<>(restricted); // list is being wrapped by the set to improve performance
    
    return map.values().stream()          // Stream<String>
        .map(str -> str.split(delimiter)) // Stream<String[]>
        .filter(arr -> Arrays.stream(arr).anyMatch(targetValue::equals))     // contain the target value
        .filter(arr -> Arrays.stream(arr).anyMatch(restrictedSet::contains)) // contains any of the restricted values
        .map(arr -> String.join(delimiter, arr))                             // Stream<String>
        .map(str -> String.format("%s %s %s", str, errorMessage, targetValue))
        .collect(Collectors.toList());
}

main()-演示

public static void main(String[] args) {
    Map<String, String> roleMap =
        Map.of("1","A", "2","B;C;D", "3","A;C");
    
    List<String> restrictedValues = List.of("B", "C");
    
    String errorMessage = " combination can't be used with ";
    String targetValue = "A";

    System.out.println(getErrorList(restrictedValues, roleMap, targetValue, errorMessage, ";"));
}

100

[A;C  combination can't be used with  A]