How do the approaches differ when using JDBCTemplate and Criteria API for database work?

JDBCTemplate and Criteria API are two different approaches for working with databases in Java, but they serve different purposes and operate at different levels of abstraction.

• JDBCTemplate is part of the Spring Framework, simplifying JDBC operations. It allows executing SQL queries directly, managing connections, prepared statements, and result processing. It is used when you need to write specific SQL queries and control them.

• Criteria API is part of JPA (Java Persistence API), which enables building database queries programmatically using an object-oriented approach. Instead of writing SQL or JPQL, you create queries through methods, which enhances type safety and ease of dynamic query construction.

Main differences:

Aspect	JDBCTemplate	Criteria API
Level of abstraction	Low (working directly with SQL)	High (object-oriented)
Query types	SQL	JPA Criteria (objects and metamodel)
Flexibility	High, but requires SQL knowledge	High for dynamic queries
Type safety	Low (SQL strings)	High (compile-time query checking)

Example of using JDBCTemplate:

String sql = "SELECT * FROM users WHERE id = ?";
User user = jdbcTemplate.queryForObject(sql, new Object[]{id}, new UserRowMapper());

Example of Criteria API (JPA):

CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<User> cq = cb.createQuery(User.class);
Root<User> user = cq.from(User.class);
cq.select(user).where(cb.equal(user.get("id"), id));
User result = entityManager.createQuery(cq).getSingleResult();