Question

How do I use the JdbcTemplate.query()/queryForList() to run a query using namedParameter and store the result set into a List of ‘User’s?

User Class:

public class User {

    String name = null;
    String id = null;

    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public String getId() {
        return name;
    }
    public void setId(String id) {
        this.id = id;
    }
}

Query:

SELECT name, id FROM USERS where email=:email

I’m looking for something like:

ArrayList<User> userList = jdbcTemplate.query(sql_query, 
                                              ...some_mapper..., etc);

Answer 1

Seems like the answer to the question is not available at one place, on the Internet. Here’s what I found out:

For adding the resultset into a List<>, we can use the NamedParameterJdbcTemplate.query() function:

NamedParameterJdbcTemplate jdbcTemplate;

ArrayList<User> usersSearchResult = (ArrayList<User>) jdbcTemplate.query(
  USER_LIST_TP_query,
  namedParameters,
  new RowMapperResultSetExtractor<User>(new UserRowMapper(), 20));

We also have to define a custom RowMapperResultSetExtractor so that JDBC can understand how to convert each row in the result set to the type User.

private class UserRowMapper implements RowMapper<User> {

  public User mapRow(ResultSet rs, int rowNum) throws SQLException {
    User user = new User();

    user.setId(rs.getString("ID"));
    user.setName(rs.getString("NAME"));

    return user;
  }
}