列表数据包含其他列表中的所有确切数据

我喜欢用 Predicate 当我想对我为什么要编写某段代码进行功能性展望时。

我们可以根据您的情况,为每个您需要的人创建一个谓词,然后将它们结合起来进行概述。以下是一个示例:

   public static Predicate<String> isExistingPMaster(List<String> pCodes) {
        return pCodes::contains;
   }

    public static Predicate<String> isExistingLMaster(List<String> lCodes) {
        return lCodes::contains; 
     /*
      * here we manage a list of lCodes but it also could be 
      * a single string with an equals() as in your question.
      *
      */
    }

    public static Predicate<String> isExistingInMaster(List<String> pCodes, List<String> lCodes) {
        return isExistingPMaster(pCodes).or(isExistingLMaster(lCodes));
    }

当创建谓词时,我们可以直接在流中使用它们:

List<String> mixedOfLAndPCodes = Arrays.asList("L123", "P123", "P234", "", "P2345", "");
List<String> masterPCodes = Arrays.asList("P123", "P234", "P2345", "P111", "P23456");
List<String> masterLCode = Arrays.asList("L123", "L125");

mixedOfLAndPCodes.stream().filter(isExistingInMaster(masterPCodes, masterLCode));

它运行良好,甚至非开发人员也能在一定程度上读取。