Using java change method

Question

How I change the database using the method changes in a Testaaltera class. I use the model gets and sets to change the data? I need to use the Search(int id) method to return an object?

//pesquisa pelo id e retorna um contato
public Contato pesquisarId(int id) {

    try {
        String sql = "select * from contatos where id = " + id;

        Contato contato = new Contato();

        PreparedStatement stmt = this.connection.prepareStatement(sql);

        ResultSet rs = stmt.executeQuery();

        while(rs.next()) {
            contato.setId(rs.getLong("id"));
            contato.setNome(rs.getString("nome"));
            contato.setEmail(rs.getString("email"));
            contato.setEndereco(rs.getString("endereco"));

            Calendar data = Calendar.getInstance();
            data.setTime(rs.getDate("dataNascimento"));
            contato.setDataNascimento(data);

        }

        rs.close();
        stmt.close();
        return contato;

    } catch (SQLException e) {
        throw new RuntimeException(e);
    }
}

//altera
public void altera(Contato contato) {

    String sql = "update contatos set nome=?, email=? where id = id";

    try {
        PreparedStatement stmt = connection.prepareStatement(sql);

         stmt.setString(1, contato.getNome());
         stmt.setString(2, contato.getEmail());
         stmt.setString(3, contato.getEndereco());
         stmt.setDate(4, new Date(contato.getDataNascimento().getTimeInMillis()));
         stmt.setLong(5, contato.getId());

         stmt.execute();
         stmt.close();
    } catch (SQLException e) {
        throw new RuntimeException(e);
    }
}

Summarizing how it would look the class alters?

    package br.com.caelum.jdbc.teste;

import br.com.caelum.jdbc.dao.ContatoDao;
import br.com.caelum.jdbc.modelo.Contato;

public class TesteAltera {

    public static void main(String[] args) {

        ContatoDao dao = new ContatoDao();

        Contato contato = dao.pesquisarId(1);


        dao.altera(contato);

    }

}

Answer 1

The class should look something like this:

public class TesteAltera {

public static void main(String[] args) {

    ContatoDao dao = new ContatoDao();

    Contato contato = dao.pesquisarId(1);

    contato.setNome("Ciclano");
    contato.setEmail("[email protected]");
    contato.setEndereco("Av. das Nações, 147");
    Calendar novaData = Calendar.getInstance();

    contato.setDataNascimento(novaData);

    dao.altera(contato);

}

}

In order for you to change a database record within a Java program, you first need to retrieve it and place its values within an object. In this case, contato.

After this, you change its values to the desired ones and finally, have the object be persisted by the method altera() so that the database data is changed according to the data that is in the object.

Answer 2

The class was like this:

    package br.com.caelum.jdbc.teste;

import java.util.Calendar;

import br.com.caelum.jdbc.dao.ContatoDao;
import br.com.caelum.jdbc.modelo.Contato;

public class TesteAltera {

    public static void main(String[] args) {

        ContatoDao dao = new ContatoDao();

        Contato contato = new Contato();

        long id = 1;

        contato.setId(id);
        contato.setNome("Nathalia");
        contato.setEmail("[email protected]");
        contato.setEndereco("Av. Paula Ferreira");
        Calendar novaData = Calendar.getInstance();

        contato.setDataNascimento(novaData);

        dao.altera(contato);

    }

}