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Spring NamedParameterJdbcTemplate Tutorial

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Spring NamedParameterJdbcTemplate Tutorial

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Learn how to create flexible schemas in a relational database using SQL for JSON.

The NamedParameterJdbcTemplate class helps you specify the named parameters insted of classic placeholder('?') argument. Named parameters improves readiablity and are easier to maintain.

package com.vaannila.dao;

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.HashMap;
import java.util.Map;

import javax.sql.DataSource;

import org.springframework.jdbc.core.RowMapper;
import org.springframework.jdbc.core.namedparam.MapSqlParameterSource;
import org.springframework.jdbc.core.namedparam.NamedParameterJdbcTemplate;
import org.springframework.jdbc.core.namedparam.SqlParameterSource;

import com.vaannila.domain.Forum;

public class ForumDAOImpl implements ForumDAO {

	private NamedParameterJdbcTemplate namedParameterJdbcTemplate;

	public void setDataSource(DataSource dataSource) {
	    this.namedParameterJdbcTemplate = new NamedParameterJdbcTemplate(dataSource);
	}

	public void insertForum(Forum forum) {
		String query = "INSERT INTO FORUMS (FORUM_ID, FORUM_NAME, FORUM_DESC) VALUES (:forumId,:forumName,:forumDesc)";
		Map namedParameters = new HashMap();
		namedParameters.put("forumId", Integer.valueOf(forum.getForumId()));
		namedParameters.put("forumName", forum.getForumName());
		namedParameters.put("forumDesc", forum.getForumDesc());
		namedParameterJdbcTemplate.update(query, namedParameters);
	}
	
	public Forum selectForum(int forumId) {
		String query = "SELECT * FROM FORUMS WHERE FORUM_ID=:forumId";
		SqlParameterSource namedParameters = new MapSqlParameterSource("forumId", Integer.valueOf(forumId));

		return (Forum) namedParameterJdbcTemplate.queryForObject(query,
				namedParameters, new RowMapper() {
			public Object mapRow(ResultSet resultSet, int rowNum)
					throws SQLException {
				return new Forum(resultSet.getInt("FORUM_ID"), resultSet.getString("FORUM_NAME"), resultSet.getString("FORUM_DESC"));
			}
		});
	}

}

The named parameter values can be specified using a map, where the parameter name serves as the key. You can also map the sql parameters using the MapSqlParameterSource class.

You can download and try the example here.

Source : Download
Source + Lib : Download

 

Create flexible schemas using dynamic columns for semi-structured data. Learn how.

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