Spring JDBC Plus

Spring JDBC Plus provides Spring Data JDBC based extension. It provides necessary features when writing more complex SQL than the functions supported by CrudRepository. If you need to use Spring Data JDBC's Persistence features and SQL execution function in combination, Spring JDBC Plus may be an appropriate choice.

Features

• Support for executing custom SQL SELECT statements

• Provide BeanParameterSource, MapParameterSource, EntityParameterSource

• Provide parameter source converters such as Java8Time,Enum, etc.

• Entity mapping support for complex table join SELECT results

• AggregateResultSet supports mapping of 1: N result data to Aggregate object graph by LEFT OUTER JOIN lookup

• JdbcRepository provides insert / update syntax

• Support for setting Reactive (Flux / Mono) type as the return type of CustomRepository method

• User Guide

Getting Started (Spring Boot Starter Data JDBC Plus SQL)

• Gradle

  buildscript {
      repositories {
          mavenCentral()
          mavenLocal()
          maven {
              url "https://repo.spring.io/milestone/"
          }
      }
      dependencies {
          classpath("org.springframework.boot:spring-boot-gradle-plugin:3.2.3")
      }
  }
  
  dependencies {
      implementation("org.springframework.boot:spring-boot-starter-data-jdbc")
      implementation("com.navercorp.spring:spring-boot-starter-data-jdbc-plus-sql:3.2.3")
  }

• Maven

  <parent>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-parent</artifactId>
      <version>3.2.3</version>
      <relativePath/>
  </parent>
  
  <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-data-jdbc</artifactId>
  </dependency>
  
  <dependency>
      <groupId>com.navercorp.spring</groupId>
      <artifactId>spring-boot-starter-data-jdbc-plus-sql</artifactId>
      <version>3.2.3</version>
  </dependency>

• Java Codes

  @Table("n_order")
  @Data
  public class Order {
      @Id
      @Column("order_no")
      private Long orderNo;
  
      @Column("price")
      private long price;
  
      @Column("purchaser_no")
      private String purchaserNo;
  }
  
  public interface OrderRepository extends CrudRepository<Order, Long>, OrderRepositoryCustom {
  }
  
  public interface OrderRepositoryCustom {
      List<Order> findByPurchaserNo(String purchaserNo);
  }
  
  public class OrderRepositoryImpl extends JdbcRepositorySupport<Order> implements OrderRepositoryCustom {
      private final OrderSql sqls;
  
      public OrderRepositoryImpl(EntityJdbcProvider entityJdbcProvider) {
          super(Order.class, entityJdbcProvider);
          this.sql = sqls(OrderSql::new);
      }
  
      @Override
      public List<Order> findByPurchaserNo(String purchaserNo) {
          String sql = this.sql.selectByPurchaserNo();
          return find(sql, mapParameterSource()
              .addValue("purchaserNo", purchaserNo));
      }
  }

• Groovy codes for SQL

  class OrderSql extends SqlGeneratorSupport {
  
      String selectByPurchaserNo() {
          """
          SELECT ${sql.columns(Order)}
          FROM n_order
          WHERE purchaser_no = :purchaserNo
          """
      }
  }

Cautions when writing SQL

• Must use named parameters to pass parameters to SQL.
• If parameter values are concatenated directly to String, it produces bad effects.
  • May cause SQL injection vulnerability.
  • Reduce efficiency of caches in PreparedStatement and NamedParameterJdbcTemplate

Be careful when use string interpolation in Groovy and Kotlin.

• Bad 👎

  class OrderSql extends SqlGeneratorSupport {
  
      String selectByPurchaserNo(String purchaserNo) {
      """
      SELECT ${sql.columns(Order)}
      FROM n_order
      WHERE purchaser_no = '${purchaserNo}'
      """
      }
  }

• Good 👍

  class OrderSql extends SqlGeneratorSupport {
  
      String selectByPurchaserNo() {
      """
      SELECT ${sql.columns(Order)}
      FROM n_order
      WHERE purchaser_no = :purchaserNo
      """
      }
  }

Annotation Guide

@SqlTableAlias

@Value
@Builder
@Table("post")
public class PostDto {
    @Id
    Long id;

    @Column
    Post post;

    @SqlTableAlias("p_labels")
    @MappedCollection(idColumn = "board_id")
    Set<Label> labels;
}

@SqlTableAlias is used to attach a separate identifier to the table. @SqlTableAlias can be applied to class, field and method.

@SqlTableAlias is used in the form of @SqlTableAlias("value") .

@SqlFunction

@SqlTableAlias("ts")
static class TestEntityWithNonNullValue {
	@Column
	private Long testerId;

	@Column("tester_nm")
	private String testerName;

	@SqlFunction(expressions = {SqlFunction.COLUMN_NAME, "0"})
	@Column
	private int age;
}

@SqlFunction is typically used to map fields or methods of entity classes to SQL functions.

For example, it can be utilized to define default values for certain fields, or to transform values based on specific conditions.

Examples

• Java + Groovy SQL Example
• Java + Kotlin SQL Example
• Kotlin Example

Getting Help

• User Guide
• Reporting Issues

Coding Convention

• naver hackday-conventions-java
• naver/hackday-conventions-java
• checkstyle: ./rule/naver-checkstyle-rules.xml
• intellij-formatter: ./rule/naver-intellij-formatter.xml (https://naver.github.io/hackday-conventions-java/#editor-config)

Building from Source

$  ./gradlew clean build

License

   Copyright 2020-2021 NAVER Corp.

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.