Split data in JSON file based on a key value using java
问题
https://stackoverflow.com/questions/70389908/split-data-in-json-file-based-on-a-key-value-using-java
I have a json file with which has an array of product items i want to split them based on the category of the item, This is my json file looks like,
{
"items":[
{
"item-id": 123,
"name": "Cheese",
"price": 8,
"category": "Dairy"
},
{
"item-id": 124,
"name": "Milk",
"price": 23,
"category": "Dairy"
},
{
"item-id": 125,
"name": "Chicken",
"price": 100,
"category": "Meat"
},
{
"item-id": 126,
"name": "Fish",
"price": 45,
"category": "Meat"
}
]
}
i want to split them like like this,
[
{
"category":"Dairy",
"items":[
{
"item-id": 123,
"name": "Cheese",
"price": 8,
"category": "Dairy"
},
{
"item-id": 124,
"name": "Milk",
"price": 23,
"category": "Dairy"
}
]
},
{
"category":"Meat",
"items":[
{
"item-id": 125,
"name": "Chicken",
"price": 100,
"category": "Meat"
},
{
"item-id": 126,
"name": "Fish",
"price": 45,
"category": "Meat"
}
]
}
]
this is the code i tried so far but can't find way to split them like the way i wanted, I'm using java and also i am new to java
import java.io.*;
import java.util.*;
import org.json.simple.*;
import org.json.simple.parser.*;
public class ReadOrderDetails {
@SuppressWarnings("unused")
public static void main(String[] args) {
JSONParser parser = new JSONParser();
JSONObject subOrder = new JSONObject();
JSONArray gitems = new JSONArray();
JSONArray subOrders = new JSONArray();
try {
Object obj = parser.parse(new FileReader("order-details.json"));
JSONObject jsonObject = (JSONObject)obj;
String orderId = (String)jsonObject.get("orderId");
JSONArray items = (JSONArray)jsonObject.get("items");
@SuppressWarnings("rawtypes")
Iterator iterator = items.iterator();
System.out.println("Order Id:" + orderId);
while(iterator.hasNext()) {
JSONObject item = (JSONObject)iterator.next();
if(subOrders.isEmpty()) {
subOrder.put("category", item.get("category"));
gitems.add(item);
subOrder.put("items", gitems);
subOrders.add(subOrder);
} else {
Iterator subOrdersIterator = subOrders.iterator();
for(int i=0; i<subOrders.size(); i++) {
JSONObject sitem = (JSONObject) subOrdersIterator.next();
if(sitem.get("category") == item.get("category")) {
gitems.add(item);
subOrder.put("items", gitems);
subOrders.add(subOrder);
} else {
subOrder.put("category", item.get("category"));
gitems.add(item);
subOrder.put("items", gitems);
subOrders.add(subOrder);
}
}
}
}
} catch(Exception e) {
e.printStackTrace();
}
System.out.println(subOrders);
}
}
and also i'm getting an error atjava.util.ConcurrentModificationExceptionbut that's not my main question, what i really wnated a way to split them i tried couple of things didn't working
解答
将json格式数据，按items数组中的category分组。用Java实现代码较长。用Java 下的开源包 SPL 很容易写，只要1句：
A |
|
1 |
=json(file("data.json").read()).items.group(#4;~:items) |
SPL 提供了 JDBC 供 Java 调用，把上面的脚本存为 group.splx，在 Java 中以存储过程的方式调用脚本文件：
…
Class.forName("com.esproc.jdbc.InternalDriver");
con= DriverManager.getConnection("jdbc:esproc:local://");
st = con.prepareCall("call group()");
st.execute();
…
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