Main.java - master - siman_coder/CSVXML-JSON

Main.java
187 строк7 KB
siman_coder
Create: Main.java, Employee.java, build.gradle, data.csv, data.json, data.xml, data2.json
07 июл 2026, 10:35
07 июл 2026, 10:35c41a7e2
package org.example;

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.reflect.TypeToken;
import com.opencsv.CSVReader;
import com.opencsv.bean.ColumnPositionMappingStrategy;
import com.opencsv.bean.CsvToBean;
import com.opencsv.bean.CsvToBeanBuilder;

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) {

        System.out.println("=== Задача 1: CSV -> JSON ===");
        String[] columnMapping = {"id", "firstName", "lastName", "country", "age"};
        String csvFileName = "data.csv";

        List<Employee> csvList = parseCSV(columnMapping, csvFileName);
        if (csvList != null && !csvList.isEmpty()) {
            String jsonFromCsv = listToJson(csvList);
            writeString(jsonFromCsv, "data.json");
            System.out.println("CSV -> JSON успешно создан!");
        }


        System.out.println("\n=== Задача 2: XML -> JSON ===");
        String xmlFileName = "data.xml";

        List<Employee> xmlList = parseXML(xmlFileName);
        if (xmlList != null && !xmlList.isEmpty()) {
            String jsonFromXml = listToJson(xmlList);
            writeString(jsonFromXml, "data2.json");
            System.out.println("XML -> JSON успешно создан!");
        }


        System.out.println("\n=== Задача 3: JSON -> Java ===");
        String jsonFileName = "data.json";

        List<Employee> employeesFromJson = jsonToList(jsonFileName);
        if (employeesFromJson != null && !employeesFromJson.isEmpty()) {
            System.out.println("Парсинг JSON в Java объекты:");
            for (Employee emp : employeesFromJson) {
                System.out.println(emp);
            }

            String outputJson = listToJson(employeesFromJson);
            writeString(outputJson, "output.json");
            System.out.println("Результат сохранен в output.json");
        }
    }


    public static List<Employee> parseCSV(String[] columnMapping, String fileName) {
        List<Employee> employees = null;

        try (CSVReader csvReader = new CSVReader(new FileReader(fileName))) {
            ColumnPositionMappingStrategy<Employee> strategy = new ColumnPositionMappingStrategy<>();
            strategy.setType(Employee.class);
            strategy.setColumnMapping(columnMapping);

            CsvToBean<Employee> csvToBean = new CsvToBeanBuilder<Employee>(csvReader)
                    .withMappingStrategy(strategy)
                    .build();

            employees = csvToBean.parse();
            System.out.println("Прочитано " + employees.size() + " записей из CSV");
        } catch (IOException e) {
            System.err.println("Ошибка при чтении CSV: " + e.getMessage());
            e.printStackTrace();
        }

        return employees;
    }


    public static List<Employee> parseXML(String fileName) {
        List<Employee> employees = new ArrayList<>();

        try {
            // Читаем XML файл
            String xmlContent = new String(Files.readAllBytes(Paths.get(fileName)));
            System.out.println("XML содержимое:");
            System.out.println(xmlContent);

            // Разбиваем на отдельные записи employee
            String[] parts = xmlContent.split("</employee>");

            for (String part : parts) {
                if (part.contains("<employee>")) {

                    String idStr = extractTagContent(part, "id");
                    String firstName = extractTagContent(part, "firstName");
                    String lastName = extractTagContent(part, "lastName");
                    String country = extractTagContent(part, "country");
                    String ageStr = extractTagContent(part, "age");

                    if (idStr != null && firstName != null && lastName != null &&
                            country != null && ageStr != null) {

                        long id = Long.parseLong(idStr.trim());
                        int age = Integer.parseInt(ageStr.trim());

                        Employee employee = new Employee(id, firstName, lastName, country, age);
                        employees.add(employee);
                        System.out.println("Добавлен сотрудник: " + employee);
                    }
                }
            }

            System.out.println("Прочитано " + employees.size() + " записей из XML");

        } catch (Exception e) {
            System.err.println("Ошибка при чтении XML: " + e.getMessage());
            e.printStackTrace();
        }

        return employees;
    }


    private static String extractTagContent(String xml, String tag) {
        String openTag = "<" + tag + ">";
        String closeTag = "</" + tag + ">";

        int startIndex = xml.indexOf(openTag);
        if (startIndex == -1) {
            return null;
        }

        startIndex += openTag.length();
        int endIndex = xml.indexOf(closeTag, startIndex);

        if (endIndex == -1) {
            return null;
        }

        return xml.substring(startIndex, endIndex).trim();
    }


    public static String listToJson(List<Employee> list) {
        GsonBuilder builder = new GsonBuilder().setPrettyPrinting();
        Gson gson = builder.create();

        Type listType = new TypeToken<List<Employee>>() {}.getType();
        return gson.toJson(list, listType);
    }


    public static List<Employee> jsonToList(String fileName) {
        List<Employee> employees = new ArrayList<>();

        try {
            String jsonContent = new String(Files.readAllBytes(Paths.get(fileName)));
            Gson gson = new Gson();
            Type listType = new TypeToken<List<Employee>>() {}.getType();
            employees = gson.fromJson(jsonContent, listType);
            System.out.println("Распаршено " + employees.size() + " объектов из JSON");
        } catch (IOException e) {
            System.err.println("Ошибка чтении JSON: " + e.getMessage());
            e.printStackTrace();
        }

        return employees;
    }


    public static void writeString(String json, String fileName) {
        try (FileWriter fileWriter = new FileWriter(fileName)) {
            fileWriter.write(json);
            System.out.println("Файл " + fileName + " успешно создан");
        } catch (IOException e) {
            System.err.println("Ошибка при записи файла: " + e.getMessage());
            e.printStackTrace();
        }
    }
}