Spring JDBC — JdbcClient (Spring Framework 7+)
Apply Spring JDBC guidelines with JdbcClient as the default; use JdbcTemplate / NamedParameterJdbcTemplate only for legacy code or APIs not covered by JdbcClient (batch updates, KeyHolder, RowCallbackHandler streaming).
What is covered in this Skill?
- Parameterized SQL (never concatenate user input)
- JdbcClient fluent API (Spring Framework 7+) — preferred for queries and updates
- Named parameters via JdbcClient; NamedParameterJdbcTemplate for legacy migration
- RowMapper, query(Class), and records
- Batch operations and generated keys (JdbcTemplate / JdbcOperations where needed)
- Safe handling of generated keys (KeyHolder; single-row JdbcClient updates)
- Service-layer @Transactional boundaries
- Read-only transactions (@Transactional(readOnly = true))
- Safe single-row access (optional() / findFirst() vs queryForObject)
- Streaming large result sets (RowCallbackHandler, ResultSetExtractor)
- DataAccessException handling (DuplicateKeyException, EmptyResultDataAccessException)
- @JdbcTest slice testing with @Sql fixtures
Scope: Apply recommendations based on the reference rules and good/bad code examples.
Constraints
Before applying any Spring JDBC changes, ensure the project compiles. If compilation fails, stop immediately. After applying improvements, run full verification.
- MANDATORY: Run
./mvnw compile or mvn compile before applying any change
- SAFETY: If compilation fails, stop immediately
- VERIFY: Run
./mvnw clean verify or mvn clean verify after applying improvements
- SQL INJECTION: Never concatenate untrusted input into SQL strings — always use bind parameters
- BEFORE APPLYING: Read the reference for detailed rules and good/bad patterns
When to use this skill
- Review Java code for Spring JDBC (JdbcTemplate, JdbcClient, NamedParameterJdbcTemplate)
- Apply best practices for Spring JDBC data access in Java code
- Detect and fix SQL injection risks in JDBC code
- Improve transaction boundaries or exception handling for JDBC operations
- Review JdbcClient usage in Spring Framework 7
Workflow
- Read reference and assess project context
Read references/311-frameworks-spring-jdbc.md and inspect the current project setup before proposing changes.
- Gather scope and decide target improvements
Identify requested outcomes, constraints, and the minimum safe set of changes to apply.
- Apply framework-aligned changes
Implement or refactor configuration/code following the reference patterns and project conventions.
- Run verification and report results
Execute appropriate build/tests and summarize what changed, what was verified, and any follow-up actions.
Reference
For detailed guidance, examples, and constraints, see references/311-frameworks-spring-jdbc.md.