如何在数组列表java spring中获取最大值答案

【问题标题】：how to get max values in array list java spring如何在数组列表java spring中获取最大值
【发布时间】：2021-12-18 10:20:16
【问题描述】：

我有要求：

"questionType": "questionType",
    "question": [
        {
            "questionId": "questionIdFirst",
            "answer": [
                {
                    "input": "input1",
                    "answerOption": [
                        {
                            "answerId": "AnswerId1",
                            "score": 7
                        }
                    ]
                },
                {
                    "input": "input2",
                    "answerOption": [
                        {
                            "answerId": "AnswerId2",
                            "score": 8
                        }
                    ]
                }
            ]
        },
        {
            "questionId": "questionIdSecond",
            "answer": [
                {
                    "input": "input3",
                    "answerOption": [
                        {
                            "answerId": "answerId",
                            "score": 9
                        }
                    ]
                },
                {
                    "input": "input4",
                    "answerOption": [
                        {
                            "answerId": "answerId",
                            "score": 10
                        }
                    ]
                }
            ]
        }
    ]
}

我想通过流过滤器或 foreach 在对象 answerOption 中获得 maxValues 分数，我该怎么做？

我尝试这样做但无法解决：

input.getQuestionnaire().getQuestion().stream()
                    .forEach(quest -> quest.getAnswer().stream()
                            .forEach(answer -> answer.getAnswerOption()
                                    .stream().max(Comparator.comparing(AnswerOption::getScore))));

然后，在我想获取 maxValues 时，我选择 DB，然后我想将 answerOption 替换为请求样本到数据库

【问题讨论】：

标签： java arrays spring multidimensional-array foreach

【解决方案1】：

要在Questionnaire 中检索最高分数AnswerOption，请尝试以下操作（您需要flatMap 来展平内部列表并获得最大比较器结果作为输出）

final Optional<AnswerOption> max = input.getQuestionnaire().getQuestion().stream().map(Question::getAnswer)
        .flatMap(Collection::stream)
        .map(Answer::getAnswerOption).flatMap(Collection::stream)
        .max(Comparator.comparing(AnswerOption::getScore));

【讨论】：