how to map a list of pojos in jdbcTemplate query without using a RowMapper class or BeanRowMapper

Question

i'm trying to fill a list pojos using jdbcTemplate but i dont want to create a RowMapper class for every pojo in my domain,also i have less atributes in my domain classes and i have more in my tables in the databases so i can't use BeanRowMapper, i found a example in this website http://www.mkyong.com/spring/spring-jdbctemplate-querying-examples/

but my problem is that this example didn't worked at firts

the example is the following one:

public List<Customer> findAll(){

    String sql = "SELECT * FROM CUSTOMER";

    List<Customer> customers = new ArrayList<Customer>();

    List<Map> rows = getJdbcTemplate().queryForList(sql);
    for (Map row : rows) {
        Customer customer = new Customer();
        customer.setCustId((Long)(row.get("CUST_ID")));
        customer.setName((String)row.get("NAME"));
        customer.setAge((Integer)row.get("AGE"));
        customers.add(customer);
    }

    return customers;
}

but this example was giving me a error in this line

List<Map> rows = getJdbcTemplate().queryForList(sql);

the error was this:

Error   incompatible types: java.util.List<java.util.Map<java.lang.String,java.lang.Object>> cannot be converted to java.util.List<java.util.Map>   

so netbeans after i right clicked the line, netbeans changed the line to this

List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);

so i didn't longer have that error, but now i method returns a list full of null objects, here is my method after the changes

 @Override
public ArrayList<Rol> findAll() {

    ArrayList<User> listOfUsers=  null;

    try 
    {
       String sql = "select * from User";
       listOfUsers =  new ArrayList<User>();

       List<Map<String, Object>> rows = jdbcTemplate.queryForList(sql);
       for (Map row : rows) 
       {
            User user= new User ();
            user.setName((String)(row.get("name")));
            user.setLastName((String)row.get("lastName"));
            user.setType((String)row.get("type"));


            listOfUsers .add(user);
       }
    } 
    catch (DataAccessException dataAccessException) 
    {

        dataAccessException.printStackTrace();
    }
    catch(Exception e) 
    {

        e.printStackTrace();
    }

    return listOfUsers;
}

Solution

This code is working in one of my projects:

List<Map<String, Object>> rows = administradoresDao.list();
    List<Administrador> usuarios = new ArrayList<>();

    for (Map<String, Object> row : rows) {
        Administrador usuario = new Administrador();
        usuario.setId(Integer.valueOf(row.get("id").toString()));
        usuario.setNombre(row.get("nombre").toString()+ " "+row.get("a_pat").toString()+" "+row.get("a_mat").toString());
        usuario.setDependencia(row.get("dependencia").toString());
        usuario.setEmail(row.get("email").toString());
        usuario.setTelefono(row.get("telefono").toString());
        usuario.setExtension(row.get("extension").toString());
        usuarios.add(usuario);
    }

The DAO:

public List<Map<String, Object>> list() {
    return jdbcTemplate.queryForList("Select * from Administradores");
}

Comments

[stackUser2000]

i should talk to you in spanish hehe but i don't know if that is agaisnt the rules, i tried your code but it give me a null pointer exception in this line @José Arcángel List<Map<String, Object>> rows = jdbcTemplate.queryForList("Select * from Usuario"); i debug the code and is actually a InvalidTargetException, i dont know why the method queryForList is not returning nothing.

[José Arcángel]

That sounds like some spring configuration problem or some injection problem. Did you add the "@Autowire" in the jdbcTemplate? Also, check if your class is included in the injection with "@Component", "@Service" or "@Repository"