将 JSON 数组数组转换为对象映射（Java）
[英]Convert JSON array of arrays to map of objects (Java)
问题描述
我有使用 Java、Apache POI 和 Jackson 从 Excel 文件中提取到 JSON 结构的数据。 生成的 JSON 数据结构如下所示：
{
"fileName" : "C:\\Users\\jgagnon\\sample_data\\PDM_BOM.xlsx",
"sheets" : [ {
"name" : "PDM_BOM",
"data" : [ [ "BRANCH", "PARENT ITEM NUMBER", "2ND ITEM NUMBER", "QUANTITY REQUIRED", "UNIT OF MEASURE", "ISSUE TYPE CODE", "LINE TYPE", "STOCK TYPE", "TYPE BOM", "LINE NUMBER", "OPERATING SEQUENCE", "EFFECTIVE FROM DATE", "EFFECTIVE THRU DATE", "DRAWING NUMBER", "UNIT COST", "SCRAP PERCENT" ],
[ "B20", "208E8840040", "5P884LPFSR2", 0.32031, "LB", "I", "S", "M", "M", 1.0, 10.0, "09/11/13", "12/31/40", null, 0.0, 0.0 ],
[ "B20", "208E8840168", "5P884LPFSR2", 1.36, "LB", "I", "S", "M", "M", 1.0, 10.0, "02/26/08", "12/31/40", null, 0.0, 0.0 ],
[ "B20", "208E8840172", "5P884LPFSR2", 1.3924, "LB", "I", "S", "M", "M", 1.0, 10.0, "02/26/08", "12/31/40", null, 0.0, 0.0 ],
[ "B20", "208E8840180", "5P884LPFSR2", 1.4565, "LB", "I", "S", "P", "M", 1.0, 10.0, "03/04/09", "12/31/40", null, 0.0, 0.0 ],
[ "B20", "21PPH150166", "8P315TPMRG", 1.39629, "LB", "I", "S", "M", "M", 1.0, 10.0, "03/05/18", "12/31/40", null, 0.0, 0.0 ] ],
"maxCols" : 16,
"maxRows" : 14996
} ]
}
在data元素中，本质上有一个数组数组，代表工作表中的所有行。 第一行数组是后面数据行的列标题。
我希望能够重组data ，使其采用对象映射的形式，其中每个键是（在本例中） PARENT ITEM NUMBER列中的值。 与键关联的映射值将是一个 JSON 对象，由当前数据行的列标题和列值的键/值对组成。
因此，使用上面的示例，我最终会得到这样的结果：（我的 JSON 语法/结构可能不正确）
{
"data": {
"208E8840040": {
"BRANCH": "B20",
"PARENT ITEM NUMBER": "208E8840040",
"2ND ITEM NUMBER": "5P884LPFSR2",
"QUANTITY REQUIRED": 0.32031,
"UNIT OF MEASURE": "LB",
"ISSUE TYPE CODE": "I",
"LINE TYPE": "S",
"STOCK TYPE": "M",
"TYPE BOM": "M",
"LINE NUMBER": 1.0,
"OPERATING SEQUENCE": 10.0,
"EFFECTIVE FROM DATE": "09/11/13",
"EFFECTIVE THRU DATE": "12/31/40",
"DRAWING NUMBER": null,
"UNIT COST": 0.0,
"SCRAP PERCENT": 0.0
},
"208E8840168": {
"BRANCH": "B20",
"PARENT ITEM NUMBER": "208E8840168",
"2ND ITEM NUMBER": "5P884LPFSR2",
"QUANTITY REQUIRED": 1.36,
...
},
...
}
}
我正在寻找一种将前者转换为后者的方法。
更新：
我才意识到我遗漏了一个重要的细节。
此工作表（表）中的数据基本上由PARENT ITEM NUMBER列键入。 但是，尽管该列是主要标识符，但它在表中并不总是唯一的。
经常有这样的情况，即有多行具有相同的PARENT ITEM NUMBER值。 这些行中的每一行都包含有关构成“父项”（将它们视为子项）的元素的信息。 这些子项目由第 2 个2ND ITEM NUMBER列标识。
此外，许多子项在表中将有自己的行，其中PARENT ITEM NUMBER项PARENT ITEM NUMBER是由PARENT ITEM NUMBER项的2ND ITEM NUMBER项编号标识的子项编号。 您可能已经猜到，这些子项可以有自己的子项，依此类推。
基本上，这是相关数据的多个层次结构的表格表示。 对于多个父项，一些子项将出现（被重复使用）。
我不知道这以什么方式使我正在尝试做的事情变得复杂。
更新：
感谢https://stackoverflow.com/users/51591/micha%c5%82-ziober的最初想法。 我稍微修改了它以生成子项列表的映射。 修改后的代码如下：
public String convertToJson(File jsonFile) throws IOException {
ArrayNode arrayNode = readDataArray(jsonFile);
List<Map<String, JsonNode>> rowMaps = convertArrayToMaps(arrayNode);
Map<Object, List<Map<String, JsonNode>>> dataMap = rowMaps.stream()
.collect(Collectors.groupingBy(map -> map.get("PARENT ITEM NUMBER").textValue()));
return jsonMapper.writeValueAsString(Collections.singletonMap("data", dataMap));
}
下面是一个输出示例：
{
"data" : {
"MTDMN97PJ1A9" : [ { <- 1 child
"BRANCH" : "B70",
"PARENT ITEM NUMBER" : "MTDMN97PJ1A9",
"2ND ITEM NUMBER" : "MTDMN970144XO",
"QUANTITY REQUIRED" : 12.0,
"UNIT OF MEASURE" : "SY",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "01/18/19",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
} ],
"ZCP723A1152" : [ { <- 4 children
"BRANCH" : "B70",
"PARENT ITEM NUMBER" : "ZCP723A1152",
"2ND ITEM NUMBER" : "5P587UMFSD2",
"QUANTITY REQUIRED" : 2.32222,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 3.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "05/15/17",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
}, {
"BRANCH" : "B70",
"PARENT ITEM NUMBER" : "ZCP723A1152",
"2ND ITEM NUMBER" : "8P550ZPPOOLE",
"QUANTITY REQUIRED" : 2.32222,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "05/15/17",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
}, {
"BRANCH" : "B70",
"PARENT ITEM NUMBER" : "ZCP723A1152",
"2ND ITEM NUMBER" : "8P906WPPA3077",
"QUANTITY REQUIRED" : 4.64444,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 2.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "05/15/17",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
}, {
"BRANCH" : "B70",
"PARENT ITEM NUMBER" : "ZCP723A1152",
"2ND ITEM NUMBER" : "8U910LKSHBL",
"QUANTITY REQUIRED" : 2.32222,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 4.01,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "12/13/17",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
} ],
... many more entries
}
1 个解决方案
解决方案1
1 已采纳 2020-09-14 22:33:23
您可以将整个JSON负载读取为JsonNode并检索作为数组的data属性。 如果我们可以假设第一个元素始终是名称数组并且所有其他元素的大小相等，则您可以手动创建Map并将其序列化回JSON 。 一个棘手的部分是如何为结果JSON生成唯一的键值。 示例代码可能如下所示：
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.fasterxml.jackson.databind.node.ArrayNode;
import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;
public class Excel2JonsApp {
public static void main(String[] args) throws IOException {
File jsonFile = new File("./resource/test.json").getAbsoluteFile();
Excel2JsonMapper mapper = new Excel2JsonMapper();
String json = mapper.convertToJson(jsonFile);
System.out.println(json);
}
}
class Excel2JsonMapper {
private final ObjectMapper jsonMapper;
Excel2JsonMapper() {
this.jsonMapper = createJsonMapper();
}
private ObjectMapper createJsonMapper() {
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
return mapper;
}
String convertToJson(File jsonFile) throws IOException {
ArrayNode arrayNode = readDataArray(jsonFile);
Map<Object, Map<String, JsonNode>> dataMap = convertArrayToMaps(arrayNode)
.stream()
.collect(Collectors.toMap(
map -> map.get("PARENT ITEM NUMBER").textValue(), //key generator function
Function.identity()));
return jsonMapper.writeValueAsString(Collections.singletonMap("data", dataMap));
}
private List<Map<String, JsonNode>> convertArrayToMaps(ArrayNode arrayNode) {
ArrayNode names = (ArrayNode) arrayNode.get(0);
Iterator<JsonNode> iterator = arrayNode.iterator();
iterator.next();// skip names
List<Map<String, JsonNode>> list = new ArrayList<>();
while (iterator.hasNext()) {
ArrayNode values = (ArrayNode) iterator.next();
Map<String, JsonNode> map = new LinkedHashMap<>();
for (int i = 0; i < names.size(); i++) {
map.put(names.get(i).textValue(), values.get(i));
}
list.add(map);
}
return list;
}
private ArrayNode readDataArray(File jsonFile) throws IOException {
JsonNode root = jsonMapper.readTree(jsonFile);
return (ArrayNode) root.at("/sheets/0/data");
}
}
上面的代码打印：
{
"data" : {
"208E8840168" : {
"BRANCH" : "B20",
"PARENT ITEM NUMBER" : "208E8840168",
"2ND ITEM NUMBER" : "5P884LPFSR2",
"QUANTITY REQUIRED" : 1.36,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "02/26/08",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
},
"21PPH150166" : {
"BRANCH" : "B20",
"PARENT ITEM NUMBER" : "21PPH150166",
"2ND ITEM NUMBER" : "8P315TPMRG",
"QUANTITY REQUIRED" : 1.39629,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "03/05/18",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
},
"208E8840180" : {
"BRANCH" : "B20",
"PARENT ITEM NUMBER" : "208E8840180",
"2ND ITEM NUMBER" : "5P884LPFSR2",
"QUANTITY REQUIRED" : 1.4565,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "P",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "03/04/09",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
},
"208E8840172" : {
"BRANCH" : "B20",
"PARENT ITEM NUMBER" : "208E8840172",
"2ND ITEM NUMBER" : "5P884LPFSR2",
"QUANTITY REQUIRED" : 1.3924,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "02/26/08",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
},
"208E8840040" : {
"BRANCH" : "B20",
"PARENT ITEM NUMBER" : "208E8840040",
"2ND ITEM NUMBER" : "5P884LPFSR2",
"QUANTITY REQUIRED" : 0.32031,
"UNIT OF MEASURE" : "LB",
"ISSUE TYPE CODE" : "I",
"LINE TYPE" : "S",
"STOCK TYPE" : "M",
"TYPE BOM" : "M",
"LINE NUMBER" : 1.0,
"OPERATING SEQUENCE" : 10.0,
"EFFECTIVE FROM DATE" : "09/11/13",
"EFFECTIVE THRU DATE" : "12/31/40",
"DRAWING NUMBER" : null,
"UNIT COST" : 0.0,
"SCRAP PERCENT" : 0.0
}
}
}
Java：将数组数组的字符串表示形式转换为对象列表
[英]Java: Convert string representation of array of arrays to an List of Objects
声明:本站的技术帖子网页，遵循CC BY-SA 4.0协议，如果您需要转载，请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.