Java JSON数据处理：利用Josson库高效提取嵌套结构中的统计信息

[
  [
    {"word": "china", "count": 0},
    {"word": "kids", "count": 1},
    {"word": "music", "count": 0}
  ],
  [
    {"word": "china", "count": 3},
    {"word": "kids", "count": 0},
    {"word": "music", "count": 2}
  ],
  [
    {"word": "china", "count": 10},
    {"word": "kids", "count": 3},
    {"word": "music", "count": 2}
  ]
]

public class Word {
    private String text;
    private Integer min;
    private Integer max;

    // Getters and Setters
    public String getText() { return text; }
    public void setText(String text) { this.text = text; }
    public Integer getMin() { return min; }
    public void setMin(Integer min) { this.min = min; }
    public Integer getMax() { return max; }
    public void setMax(Integer max) { this.max = max; }

    @Override
    public String toString() {
        return String.format("text=%s min=%d max=%d", text, min, max);
    }
}

<dependency>
    <groupId>com.github.octomix</groupId>
    <artifactId>josson</artifactId>
    <version>1.3.0</version> <!-- 请替换为最新稳定版本 -->
</dependency>

import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.octomix.josson.Josson;

import java.util.List;

public class JsonDataProcessor {

    public static void main(String[] args) throws Exception {
        String jsonInput = "[" +
            "  [" +
            "    {\"word\": \"china\", \"count\": 0}," +
            "    {\"word\": \"kids\", \"count\": 1}," +
            "    {\"word\": \"music\", \"count\": 0}" +
            "  ]," +
            "  [" +
            "    {\"word\": \"china\", \"count\": 3}," +
            "    {\"word\": \"kids\", \"count\": 0}," +
            "    {\"word\": \"music\", \"count\": 2}" +
            "  ]," +
            "  [" +
            "    {\"word\": \"china\", \"count\": 10}," +
            "    {\"word\": \"kids\", \"count\": 3}," +
            "    {\"word\": \"music\", \"count\": 2}" +
            "  ]" +
            "]";

        // 1. 使用Josson加载JSON字符串
        Josson josson = Josson.fromJsonString(jsonInput);

        // 2. 构建Josson查询表达式进行数据转换
        // flatten(): 将所有嵌套数组扁平化为单个数组
        // group(word): 按 'word' 字段进行分组
        // map(text:word, min:elements.min(count), max:elements.max(count)):
        //   映射为新结构，其中 text 取 word 值，min 取分组内 count 的最小值，max 取分组内 count 的最大值
        JsonNode transformedNode = josson.getNode(
            "flatten()" +
            ".group(word)" +
            ".map(text:word, min:elements.min(count), max:elements.max(count))"
        );

        // 3. 使用Jackson ObjectMapper将转换后的JsonNode反序列化为POJO列表
        ObjectMapper objectMapper = new ObjectMapper();
        List<Word> words = objectMapper.convertValue(transformedNode, new TypeReference<List<Word>>() {});

        // 4. 打印结果
        words.forEach(System.out::println);
    }
}

text=china min=0 max=10
text=kids min=0 max=3
text=music min=0 max=2