JdbcTemplate

Internal

• Spring Framework
• JDBC

Overview

Basic persistence with JDBC is supported by the Spring Framework with JdbcTemplate. JdbcTemplate provides the means by which developers can perform SQL operations against a relational database without the need to retort to verbose JDBC low-level API. With JdbcTemplate, the interaction with the database is reduced to specifying the query and how to map the result of the query to the domain model object.

Spring Persistence Concepts

Spring Persistence Concepts

Spring Boot Support

To add support for JdbcTemplate to a Spring Boot project, add the following starter dependency:

dependencies {
    implementation('org.springframework.boot:spring-boot-starter-jdbc')
}

JdbcTemplate needs a database to work with. This is how to add H2 support:

dependencies {
    runtimeOnly('com.h2database:h2')
}

JdbcTemplate-Based Repository

This is a JdbcTemplate-based concrete repository implementation that conceals from the application low-level data access details while exposing a domain model-typed API, represented by the example "IngredientRepository" interface.

@Repository
public class JdbcIngredientRepository implements IngredientRepository {

    private JdbcTemplate jdbcTemplate;

    @Autowired
    public JdbcIngredientRepository(JdbcTemplate jdbcTemplate) {

        this.jdbcTemplate = jdbcTemplate;
    }

    //
    // Reading data
    //

    @Override
    public Ingredient findOne(String id) {

        return jdbcTemplate.queryForObject(
                "SELECT id, name, type from INGREDIENT WHERE id=?",
                this::mapRowToIngredient, id);
    }

    @Override
    public Iterable<Ingredient> findAll() {

        return jdbcTemplate.query(
                "SELECT id, name, type from INGREDIENT",
                this::mapRowToIngredient);
    }

    //
    // Writing data
    //

    @Override
    public Ingredient save(Ingredient ingredient) {

        jdbcTemplate.update(
                "INSERT INTO INGREDIENT (id, name, type) VALUES (?, ?, ?)",
                ingredient.getId(),
                ingredient.getName(),
                ingredient.getType().toString());

        return ingredient;
    }

    private Ingredient mapRowToIngredient(ResultSet rs, int rowNumber) throws SQLException {

        return new Ingredient(
                rs.getString("id"),
                rs.getString("name"),
                Ingredient.Type.valueOf(rs.getString("type")));
    }
}