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Build a complete CRUD application with Spring Boot - project setup, layered architecture, full CRUD operations, testing, and deployment.
Project Overview
We'll build a complete Employee Management System REST API with:
- Full CRUD operations (Create, Read, Update, Delete)
- Input validation
- Exception handling
- Pagination and sorting
- DTO pattern
- Service layer with business logic
Testing with Postman/cURL
bash example
# Create Employee
curl -X POST http://localhost:8080/api/v1/employees \
-H "Content-Type: application/json" \
-d '{"firstName":"John","lastName":"Doe","email":"john@example.com","department":"IT","salary":75000}'
# Get All Employees (paginated)
curl "http://localhost:8080/api/v1/employees?page=0&size=5&sortBy=salary&direction=desc"
# Get Employee by ID
curl http://localhost:8080/api/v1/employees/1
# Update Employee
curl -X PUT http://localhost:8080/api/v1/employees/1 \
-H "Content-Type: application/json" \
-d '{"firstName":"John","lastName":"Smith","email":"john@example.com","department":"Engineering","salary":85000}'
# Delete Employee
curl -X DELETE http://localhost:8080/api/v1/employees/1Interview Key Points
- CRUD = Create (POST), Read (GET), Update (PUT), Delete (DELETE)
- Always use DTOs to separate API contract from internal model
- Validate input with
@Valid+ Jakarta validation annotations - Use
@Transactionalfor write operations - Return proper HTTP status codes (201 Created, 404 Not Found, etc.)
- Implement global exception handling with
@RestControllerAdvice - Add pagination for list endpoints to handle large datasets
- Use Builder pattern for clean object construction
Summary
In this chapter, we learned about CRUD Application with Spring Boot in detail. Here are the key points:
- Basic introduction to the concept and why it is needed
- Syntax and structure with complete examples
- Internal working and best practices
- Real-world applications and use cases
- Common mistakes and how to avoid them
- How this topic is asked in interviews
To practice these concepts, write and run the code in your IDE and verify the output. Modify each example and experiment so that you deeply understand the concept.
Exam Focus
Revise definitions, diagrams, examples, and short-answer points for CRUD Application.
Interview Use
Prepare one clear explanation, one practical example, and one common mistake for this Java Master Course topic.
Search Terms
java-master-course, java master course, java, master, course, spring, framework, boot
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