字符串替换StringUtils.replace（）

一、代码示例：

三种替换

List knowledgeList = Optional.ofNullable(list).orElse(new ArrayList<>()).stream().map(item -> {
                if (StringUtils.contains(item.getRelevanceKnowIds(), knowledgeRobotId)) {
                    String relevanceKnowIds = item.getRelevanceKnowIds();
                    relevanceKnowIds = StringUtils.replace(relevanceKnowIds, knowledgeRobotId + ",", "");
                    relevanceKnowIds = StringUtils.replace(relevanceKnowIds, "," + knowledgeRobotId, "");
                    relevanceKnowIds = StringUtils.replace(relevanceKnowIds, knowledgeRobotId, "");
                    item.setRelevanceKnowIds(relevanceKnowIds);
                    return item;
                }
                return item;
            }).collect(Collectors.toList());

二、原理

      StringUtils.replace(null, *, *)        = null
      StringUtils.replace("", *, *)          = ""
      StringUtils.replace("any", null, *)    = "any"
      StringUtils.replace("any", *, null)    = "any"
      StringUtils.replace("any", "", *)      = "any"
      StringUtils.replace("aba", "a", null)  = "aba"
      StringUtils.replace("aba", "a", "")    = "b"
      StringUtils.replace("aba", "a", "z")   = "zbz"