Java根据分组key构建合并数据集的代码详解

[{sub_product_name=生活费-生意贷, approval_result=其它, marital_state=3},
 {sub_product_name=生活费-生意贷, approval_result=其它, marital_state=3}, 
 {sub_product_name=生活费-生意贷, approval_result=通过, marital_state=3},
 {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3}, 
 {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3}, 
 {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3}, 
 {sub_product_name=生活费-联合贷, approval_result=其他, marital_state=3}]

# 参数说明：
{
	"colspan": 1,// 合并列数（固定为1）
	"col": 0, //起始第N列
	"rowspan":  3//合并行数
	"row": 0, //起始第N行
}


#输出对象数据：
{colspan=1, col=0, rowspan=3, row=0},
{colspan=1, col=0, rowspan=4, row=3},
{colspan=1, col=1, rowspan=2, row=0},
{colspan=1, col=1, rowspan=3, row=3}

import com.wiseco.model.mgt.server.web.vo.resp.ReportOutputDto;

import java.util.*;

public class MergeCells {
    
   /**
     * .
     * 构建返回对象
     *
     * @param varSummary    原始数据
     * @param targetColumns 动态指定需要合并的值
     * @return
     */
    public static List<Map<String, Integer>> buildMergeInfo(
            List<Map<String, Object>> varSummary,
            List<String> targetColumns) {

        List<Map<String, Integer>> result = new ArrayList<>();
        if (varSummary == null || varSummary.isEmpty() || targetColumns == null || targetColumns.isEmpty()) {
            return result;
        }

        int n = varSummary.size();
        int[] groupStarts = new int[targetColumns.size()];  // 每列当前分组的起始行索引
        String[] currentValues = new String[targetColumns.size()];  // 每列当前分组的值

        // 初始化第一行的值
        for (int col = 0; col < targetColumns.size(); col++) {
            currentValues[col] = getStringValue(varSummary.get(0), targetColumns.get(col));
        }

        // 遍历每一行（从第1行开始）
        for (int row = 1; row <= n; row++) {
            // 检查每列是否需要结束当前分组
            for (int col = 0; col < targetColumns.size(); col++) {
                String currentVal = (row < n) ?
                        getStringValue(varSummary.get(row), targetColumns.get(col)) :
                        null;

                // 如果列值变化或是最后一行
                boolean valueChanged = row < n && !Objects.equals(currentVal, currentValues[col]);
                if (valueChanged || row == n) {
                    int groupSize = row - groupStarts[col];
                    if (groupSize > 1) {
                        result.add(createCellInfo(groupStarts[col], col, groupSize, 1));
                    }

                    // 更新当前分组起始位置
                    groupStarts[col] = row;

                    // 重置当前值
                    if (row < n) {
                        currentValues[col] = currentVal;
                    }

                    // 当外层列值变化时，重置内层列的分组
                    for (int innerCol = col + 1; innerCol < targetColumns.size(); innerCol++) {
                        groupStarts[innerCol] = row;
                        if (row < n) {
                            currentValues[innerCol] = getStringValue(varSummary.get(row), targetColumns.get(innerCol));
                        }
                    }

                    // 跳出内层列循环，避免重复处理
                    break;
                }
            }
        }
        return result;
    }


	/**
     * .
     * 构建输出对象
     *
     * @param row     起始行
     * @param col     起始列
     * @param rowspan 合并行数
     * @param colspan 合并列数（固定值1）
     * @return
     */
    private static Map<String, Integer> createCellInfo(int row, int col, int rowspan, int colspan) {
        Map<String, Integer> cell = new HashMap<>();
        cell.put("row", row);
        cell.put("col", col);
        cell.put("rowspan", rowspan);
        cell.put("colspan", colspan);
        return cell;
    }


    private static String getStringValue(Map<String, Object> map, String key) {
        Object value = map.get(key);
        return (value != null) ? value.toString() : null;
    }

}

public static void main(String[] args) {
        // 示例数据构造
        List<Map<String, Object>> varSummary = new ArrayList<>();

        Map<String, Object> map1 = new HashMap<>();
        map1.put("sub_product_name", "生活费-生意贷");
        map1.put("approval_result", "其它");
        map1.put("marital_state", 3);
        varSummary.add(map1);

        Map<String, Object> map2 = new HashMap<>();
        map2.put("sub_product_name", "生活费-生意贷");
        map2.put("approval_result", "其它");
        map2.put("marital_state", 3);
        varSummary.add(map2);

        Map<String, Object> map3 = new HashMap<>();
        map3.put("sub_product_name", "生活费-生意贷");
        map3.put("approval_result", "通过");
        map3.put("marital_state", 3);
        varSummary.add(map3);


        Map<String, Object> map4 = new HashMap<>();
        map4.put("sub_product_name", "生活费-联合贷");
        map4.put("approval_result", "通过");
        map4.put("marital_state", 3);
        varSummary.add(map4);

        Map<String, Object> map5 = new HashMap<>();
        map5.put("sub_product_name", "生活费-联合贷");
        map5.put("approval_result", "通过");
        map5.put("marital_state", 3);
        varSummary.add(map5);


        Map<String, Object> map6 = new HashMap<>();
        map6.put("sub_product_name", "生活费-联合贷");
        map6.put("approval_result", "通过");
        map6.put("marital_state", 3);
        varSummary.add(map6);

        Map<String, Object> map7 = new HashMap<>();
        map7.put("sub_product_name", "生活费-联合贷");
        map7.put("approval_result", "其他");
        map7.put("marital_state", 3);
        varSummary.add(map7);


        // 生成合并信息
        List<String> targetColumns = Arrays.asList("marital_state","sub_product_name");

        List<Map<String, Integer>> mergeInfo = buildMergeInfo(varSummary, targetColumns);
        System.out.println(varSummary);
        // 输出结果
        for (Map<String, Integer> cell : mergeInfo) {
            System.out.println(cell);
        }

        /* 原始数据格式
        [{sub_product_name=生活费-生意贷, approval_result=其它, marital_state=3},
        {sub_product_name=生活费-生意贷, approval_result=其它, marital_state=3},
        {sub_product_name=生活费-生意贷, approval_result=通过, marital_state=3},
        {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3},
        {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3},
        {sub_product_name=生活费-联合贷, approval_result=通过, marital_state=3},
        {sub_product_name=生活费-联合贷, approval_result=其他, marital_state=3}]
        
        构建输出对象
        {colspan=1, col=0, rowspan=3, row=0}
		{colspan=1, col=0, rowspan=4, row=3}
		{colspan=1, col=1, rowspan=2, row=0}
		{colspan=1, col=1, rowspan=3, row=3}*/
    }