Домашнее задание к 2 семинару

Задача 1

import java.io.IOException;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class dz_02_1 {
  public static void main(String[] args) throws IOException {

    // Path dir = Path.of("C:\\Program Files\\Java\\jdk-11.0.16\\conf\\management",
    // "//");
    Path dir = Paths.get("C:\\Program Files\\Java\\jdk-18.0.2.1\\bin\\server");
    try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
      for (Path entry : stream) {
        String str = entry.toString();
        String substr = str.substring(str.lastIndexOf('.') + 1);
        System.out.printf("Расширение файла: %s\n", substr);
      }
    }
  }
}

Задача 2

import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;

import org.json.simple.JSONObject;
import org.json.simple.parser.JSONParser;
import org.json.simple.parser.ParseException;

public class dz_02_2 {
  public static void main(String[] args) {

    String begin = new String("select * from students where ");

    JSONParser parser = new JSONParser();

    try (Reader reader = new FileReader("filterstring.json")) {
      JSONObject jsonObject = (JSONObject) parser.parse(reader);

      System.out.printf("Filter: %s\n", jsonObject);

      String sb = createString(begin, jsonObject);

      System.out.printf("Rezult: %s\n", sb);

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

  static String createString(String begin, JSONObject jsonObject) {
    StringBuilder sb = new StringBuilder(begin);

    for (Object key : jsonObject.keySet()) {
      String keyStr = (String) key;
      String keyvalue = (String) jsonObject.get(keyStr);

      if (!keyvalue.equals("Null")) {
        sb.append(keyStr + " = '" + keyvalue + "' and ");
      }
    }
    sb.delete(sb.lastIndexOf("and"), sb.length());

    return sb.toString();
  }
}