14 Practical Spring Boot Code Optimization Tips for Cleaner Backend Development

When discussing code optimization, many focus on theory and architecture, but adopting good coding habits can make the process simple. Below are fourteen Spring Boot tips that streamline code and enhance maintainability.

1. Define configuration file information

Store common variables in a YML file and bind them with @ConfigurationProperties instead of using @Value.

@Data
@ConfigurationProperties(prefix = "developer")
@Component
public class DeveloperProperty {
    private String name;
    private String website;
    private String qq;
    private String phoneNumber;
}

Inject the bean where needed:

@RestController
@RequiredArgsConstructor
public class PropertyController {
    final DeveloperProperty developerProperty;

    @GetMapping("/property")
    public Object index() {
        return developerProperty.getName();
    }
}

2. Use @RequiredArgsConstructor instead of @Autowired

Prefer constructor injection; Lombok’s @RequiredArgsConstructor generates the required constructor automatically.

3. Code modularization

Keep methods under 50 lines, split responsibilities, and ensure each method handles a single piece of logic.

4. Throw exceptions instead of returning error codes

Use exceptions to signal error conditions rather than returning varied messages.

5. Reduce unnecessary database queries

Avoid extra lookups; delete operations should verify existence efficiently.

6. Avoid returning null

Prefer Optional or empty collections to prevent NullPointerExceptions.

7. Limit excessive if‑else chains

Replace long if‑else blocks with strategy patterns where appropriate.

8. Keep controller logic thin

Move business logic to service layers for better maintainability.

9. Leverage IDE assistance

IDEA can suggest refactorings such as converting anonymous classes to lambda expressions.

10. Read source code of popular projects

Study high‑star open‑source repositories to learn design ideas and advanced APIs.

11. Apply design patterns

Incorporate the 23 classic design patterns to write clean and expressive code.

12. Embrace new knowledge

Continuously explore unfamiliar technologies and build demo projects to deepen understanding.

13. Master fundamental utilities

Examples:

HashMap<String, String> map = new HashMap<>();
map.put("name", "du");
for (Map.Entry<String, String> entry : map.entrySet()) {
    // process entry
}

// Optional null‑check example
public List<CatalogueTreeNode> getChild(String pid) {
    if (V.isEmpty(pid)) {
        pid = BasicDic.TEMPORARY_DIRECTORY_ROOT;
    }
    CatalogueTreeNode node = treeNodeMap.get(pid);
    return Optional.ofNullable(node)
                   .map(CatalogueTreeNode::getChild)
                   .orElse(Collections.emptyList());
}

14. Use hash‑based collections for existence checks

Prefer HashSet over ArrayList when checking element presence, achieving O(1) lookup.

HashSet<String> set = new HashSet<>();
// check if "a" exists in set
boolean exists = set.contains("a");