PersonDAO.java

package ru.alishev.springcourse.dao;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.jdbc.core.BatchPreparedStatementSetter;
import org.springframework.jdbc.core.BeanPropertyRowMapper;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;
import ru.alishev.springcourse.models.Person;

import java.sql.PreparedStatement;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;

/**
 * @author Neil Alishev
 */
@Component
public class PersonDAO {

    private final JdbcTemplate jdbcTemplate;

    @Autowired
    public PersonDAO(JdbcTemplate jdbcTemplate) {
        this.jdbcTemplate = jdbcTemplate;
    }

    public List<Person> index() {
        return jdbcTemplate.query("SELECT * FROM Person", new BeanPropertyRowMapper<>(Person.class));
    }

    public Optional<Person> show(String email) {
        return jdbcTemplate.query("SELECT * FROM Person WHERE email=?", new Object[]{email},
                new BeanPropertyRowMapper<>(Person.class)).stream().findAny();
    }

    public Person show(int id) {
        return jdbcTemplate.query("SELECT * FROM Person WHERE id=?", new Object[]{id}, new BeanPropertyRowMapper<>(Person.class))
                .stream().findAny().orElse(null);
    }

    public void save(Person person) {
        jdbcTemplate.update("INSERT INTO Person(name, age, email, address) VALUES(?, ?, ?, ?)", person.getName(), person.getAge(),
                person.getEmail(), person.getAddress());
    }

    public void update(int id, Person updatedPerson) {
        jdbcTemplate.update("UPDATE Person SET name=?, age=?, email=?, address=? WHERE id=?", updatedPerson.getName(),
                updatedPerson.getAge(), updatedPerson.getEmail(), updatedPerson.getAddress(), id);
    }

    public void delete(int id) {
        jdbcTemplate.update("DELETE FROM Person WHERE id=?", id);
    }

    //////////////////////
    // Тестируем производительность
    //////////////////////

    public void testMultipleUpdate() {
        List<Person> people = create1000People();

        long before = System.currentTimeMillis();

        for (Person person : people) {
            jdbcTemplate.update("INSERT INTO Person VALUES(?, ?, ?, ?)", person.getId(), person.getName(), person.getAge(),
                    person.getEmail());
        }

        long after = System.currentTimeMillis();
        System.out.println("Time: " + (after - before));
    }

    public void testBatchUpdate() {
        List<Person> people = create1000People();

        long before = System.currentTimeMillis();

        jdbcTemplate.batchUpdate("INSERT INTO Person VALUES(?, ?, ?, ?)",
                new BatchPreparedStatementSetter() {
                    @Override
                    public void setValues(PreparedStatement ps, int i) throws SQLException {
                        ps.setInt(1, people.get(i).getId());
                        ps.setString(2, people.get(i).getName());
                        ps.setInt(3, people.get(i).getAge());
                        ps.setString(4, people.get(i).getEmail());
                    }

                    @Override
                    public int getBatchSize() {
                        return people.size();
                    }
                });

        long after = System.currentTimeMillis();
        System.out.println("Time: " + (after - before));
    }

    private List<Person> create1000People() {
        List<Person> people = new ArrayList<>();

        for (int i = 0; i < 1000; i++)
            people.add(new Person(i, "Name" + i, 30, "test" + i + "@mail.ru", "some address"));

        return people;
    }
}