Java - 根据 ZA8CFDE6331BD49EB2AC96F8911 使用 JSON 库从 json 读取数据

Question

I have a JSON with some data and I would like to print as follows

10 REGISTER 1, KP SUM 2081,606
20 REGISTER 2 CH SUM 0,22

Where the general sum is calculated by the total sum of the items according to the code.

Following the rule, first multiply the quantity by the unit and then add all the items that have the same code.

Example:

code 10
SUM = 0,0200000 * 7,40 + 10,0000000 * 200,31 + 0,5690000 * 40,19 + 0,7890000 * 70,33

The same goes for the other codes that appear in JSON

My JSON

    [
      {
        "code": 10,
        "description": "REGISTER 1",
        "unity": "KP",
        "typeItem": "I",
        "itemCode": 1,
        "descriptionItem": "ITEM",
        "unityItem": "UN",
        "quantity": "0,0200000",
        "valueUnity": "7,40"
      },
      {
        "code": 10,
        "description": "REGISTER 1",
        "unity": "KP",
        "typeItem": "I",
        "codeItem": 2,
        "descriptionItem": "ITEM 2",
        "unityItem": "UN",
        "quantity": "10,0000000",
        "valueUnity": "200,31"
      },
      {
        "code": 10,
        "description": "REGISTER 1",
        "unity": "KP",
        "typeItem": "I",
        "codeItem": 88248,
        "descriptionItem": "ITEM 3",
        "unityItem": "H",
        "quantity": "0,5690000",
        "valueUnity": "40,19"
      },
      {
        "code": 10,
        "description": "REGISTER 1",
        "unity": "KP",
        "typeItem": "I",
        "codeItem": 88267,
        "descriptionItem": "ITEM 4",
        "unityItem": "N",
        "quantity": "0,7890000",
        "valueUnity": "70,33"
      },
      {
        "code": 20,
        "description": "REGISTER 2",
        "unity": "CH",
        "typeItem": "I",
        "codeItem": 1,
        "descriptionItem": "ITEM 1",
        "unityItem": "H",
        "quantity": "30,0000000",
        "valueUnity": "0,17"
      },
      {
        "code": 20,
         "description": "REGISTER 2",
        "unity": "CH",
        "typeItem": "I",
        "codeItem": 2,
        "descriptionItem": "ITEM 2",
        "unityItem": "H",
        "quantity": "3,0000000",
        "valueUnity": "0,07"
      }
    ]

My class Java

    public class MyJson {
    @SerializedName("code")
        @Expose
        private Integer code;

        @SerializedName("description")
        @Expose
        private String description;

        @SerializedName("unity")
        @Expose
        private String unity;

        @SerializedName("typeItem")
        @Expose
        private String typeItem;

        @SerializedName("codeItem")
        @Expose
        private Integer codeItem;

        @SerializedName("descriptionItem")
        @Expose
        private String descriptionItem;

        @SerializedName("unityItem")
        @Expose
        private String unityItem;

        @SerializedName("quantity")
        @Expose
        private String quantity;

        @SerializedName("valueUnity")
        @Expose
        private String valueUnity;

        private Double total;

    }

My Program

    public static void main(String[] args) {

            Gson gson = new Gson();

                try {

                    File jsonFile = new File("C:\\my_json.json");
                    InputStreamReader reader = new InputStreamReader(new FileInputStream(jsonFile), "UTF-8");
                    BufferedReader jsonBuffer = new BufferedReader(reader);

                    MyJson[] myJsonArray = gson.fromJson(jsonBuffer, MyJson[].class);  

                    BigDecimal valueUnity = BigDecimal.ZERO;
                    BigDecimal sumTotal = BigDecimal.ZERO;
                    //
                    Set<MyJson> list = new HashSet<>();

                    for(MyJson myJson : myJsonArray) {

                        if(checkStringNullOrEmpty(myJson.getQuantity()) && checkStringNullOrEmpty(myJson.getValueUnity())) {

                            if(myJson.getCode().equals(myJson.getCode())) {
                                String value1 = myJson.getQuantity().replaceAll( "," , "." ).trim();
                                String value2 = myJson.getValueUnity.replaceAll( "," , "." ).trim();
                                BigDecimal quantity = new BigDecimal(value1);
                                BigDecimal valueUnit = new BigDecimal(value2);
                                valueUnity = quantity.multiply(valueUnit);
                                somaTotal = sumTotal.add(valueUnity);
                                String resultado = String.format(Locale.getDefault(), "%.2f", valueUnity);
                                String sumTotal2 = String.format(Locale.getDefault(), "%.2f", sumTotal);
                                myJson.setTotal(new Double(sumTotal2.replaceAll( "," , "." ).trim()));
                                list.add(myJson);

                            }
                        }

                    }

                    for(MyJson myJson : list) {
                        StringBuilder builer = new StringBuilder();
                        builer.append(myJson.getCode()).append(" ");
                        builer.append(myJson.getDescription().toUpperCase()).append(" ");
                        builer.append(myJson.getUnity().toUpperCase()).append(" ");
                        builer.append(myJson.getTotal());

                        System.out.println(builer.toString());
                    }

                } catch (IOException e) {
                    e.printStackTrace();
                }
        }

        private static boolean checkStringNullOrEmpty(String value) {
            if(!value.isEmpty()) {
                return true;
            } else {
                return false;
            }
        }

Exit program

The calculation is being done wrong when using the Set

10 REGISTER 1, KP SUM 130,33
20 REGISTER 2 CH SUM 439,18

Answer 1

You cannot keep track of multiple running totals (ie one for each code) using one total. Instead you will need one total for each different code.

I would recommend that you use a Map<Integer, MyJson> for this purpose. This would store a number of MyJson objects which you could look up by their code. When handling each MyJson object, you check to see if you already have a MyJson object with the same code: if you do then you add to its total, otherwise you add your MyJson object to the map.

Get rid of your Set<MyJson> variable (which you have somewhat confusingly named list ) and replace it with the following

            Map<Integer, MyJson> jsonsByCode = new LinkedHashMap<>();

(You can use a HashMap<> instead of a LinkedHashMap<> here: I chose to use a LinkedHashMap<> because it keeps its entries in the same order they were inserted into it.)

Then, replace all lines from somaTotal = sumTotal.add(valueUnity);to list.add(myJson); with

                    if (jsonsByCode.containsKey(myJson.getCode())) {
                        // We've seen this code before, so add the value
                        // to the total.
                        MyJson matchingJson = jsonsByCode.get(myJson.getCode());
                        matchingJson.setTotal(matchingJson.getTotal() + valueUnity.doubleValue());
                    } else {
                        // First time seeing this code, so set its total
                        // and add it to the map.
                        myJson.setTotal(valueUnity.doubleValue());
                        jsonsByCode.put(myJson.getCode(), myJson);
                    }

(Note that BigDecimal values such as valueUnity have a .doubleValue() method on them, which is the easiest way to convert them to a double .)

Then, in the for loop below, where you are printing out the values, replace list with jsonsByCode.values() .

I made these changes to your program and it generated the following output:

10 REGISTER 1 KP 2081.60648
20 REGISTER 2 CH 5.31

---

Incidentally, your code also contains the following if statement:

 if(myJson.getCode().equals(myJson.getCode())) { //.... }

You are comparing myJson.getCode() against itself, so this condition will always be true (unless of course myJson.getCode() returns null , in which case you get a NullPointerException ). You can just get rid of this check, it doesn't do anything useful.